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Li Y, Yan Z, Li X, Yin X, Li K. UPLC-TOF-MS Method for Simultaneous Quantification of Steroid Hormones in Tissue Homogenates of Zebrafish with Solid-Phase Extraction. Molecules 2021; 26:molecules26206213. [PMID: 34684799 PMCID: PMC8539474 DOI: 10.3390/molecules26206213] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/03/2021] [Accepted: 10/13/2021] [Indexed: 11/16/2022] Open
Abstract
The quantification of steroid hormones of individual zebrafish (Danio rerio) provides perspective to understand endogenous hormone function. A UPLC–TOF–MS method was developed to provide a reproducible, sensitive, and efficient assay to determine the concentration of steroid hormones, including cortisol, testosterone, androstenedione, 11-deoxycortisol, 11-deoxycorticosterone, and 17-hydroxyprogesterone in whole-body homogenates of each zebrafish. Solid-phase extraction was used to sample matrix clean-up and acquired a recovery from 89.7% to 107.9%. The analytes were separated on an Aquity BEH C18 column using gradient elution. Mass spectrometric analysis was performed by single reaction monitoring (SRM) using positive electrospray ionization mode. The total running time was 6 min, which was greatly shortened compared with a previously reported method. The developed method exhibited excellent linearity for all the analytes, with regression coefficients higher than 0.99. The limit of detection varied between 0.1 and 0.5 ng/L and the limit of quantification was 0.5–1.7 ng/L for all analytes. The precision of the method was assessed on replicate measurements and was found to be in the ranges of 1.9 % to 6.6% and 4.3% to 8.6%, for intra- and inter-day analysis, respectively. This method was validated according to FDA guidance and applied to determine steroid hormone levels in the tissue homogenate of zebrafish acutely treated with caffeine and ethanol.
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Affiliation(s)
- Yaxi Li
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; (Y.L.); (Z.Y.); (X.L.); (X.Y.)
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhi Yan
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; (Y.L.); (Z.Y.); (X.L.); (X.Y.)
- School of Ocean, Yantai University, Yantai 264005, China
| | - Xiaodong Li
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; (Y.L.); (Z.Y.); (X.L.); (X.Y.)
| | - Xiuli Yin
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; (Y.L.); (Z.Y.); (X.L.); (X.Y.)
| | - Ke Li
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; (Y.L.); (Z.Y.); (X.L.); (X.Y.)
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
- Correspondence: ; Tel.: +86-535-210-8286
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Abstract
Liquid chromatography-mass spectrometry (LC-MS) is one of the most widely used analytical tools. High analysis volumes and sample complexity often demand more informative LC-MS acquisition schemes to improve efficiency and throughput without compromising data quality, and such a demand has been always hindered by the prerequisite that a minimum of 13-20 MS scans (data points) across an analyte peak are required for accurate quantitation. The current study systematically re-evaluated and compared the impact of different scan numbers on quantitation analysis using both triple quadrupoles mass spectrometry (TQMS) and high-resolution mass spectrometry (HRMS). Contrary to the 13-20 minimal scan prerequisite, the data obtained from a group of eight commercial drugs in the absence and presence of biological matrices suggest that 6 scans per analyte peak are sufficient to achieve highly comparable quantitation results compared to that obtained using 10 and 20 scans, respectively. The fewer minimal scan prerequisite is presumably attributed to an improved LC system and advanced column technology, better MS detector, and more intelligent peak detection and integration algorithms leading to a more symmetric peak shape and smaller peak standard deviation. As a result, more informative acquisition schemes can be broadly set up for higher throughput and more data-rich LC-MS/MS analysis as demonstrated in a hepatocyte clearance assay in which fewer MS scans executed on HRMS led to broader metabolite coverage without compromising data quality in hepatic clearance assessment. The demonstrated acquisition scheme would substantially increase the throughput, robustness, and richness of the nonregulatory analysis, which can be broadly applied in diverse fields including pharmaceutical, environmental, forensic, toxicological, and biotechnological.
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Affiliation(s)
- Jingwei Cai
- Department of Drug Metabolism and Pharmacokinetics, Genentech, Inc., South San Francisco, California 94080, United States
| | - Zhengyin Yan
- Department of Drug Metabolism and Pharmacokinetics, Genentech, Inc., South San Francisco, California 94080, United States
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Frederiksen H, Johannsen TH, Andersen SE, Albrethsen J, Landersoe SK, Petersen JH, Andersen AN, Vestergaard ET, Schorring ME, Linneberg A, Main KM, Andersson AM, Juul A. Sex-specific Estrogen Levels and Reference Intervals from Infancy to Late Adulthood Determined by LC-MS/MS. J Clin Endocrinol Metab 2020; 105:dgz196. [PMID: 31720688 PMCID: PMC7007877 DOI: 10.1210/clinem/dgz196] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 11/11/2019] [Indexed: 01/09/2023]
Abstract
CONTEXT The lack of sensitive and robust analytical methods has hindered the reliable quantification of estrogen metabolites in subjects with low concentrations. OBJECTIVE To establish sex-specific reference ranges for estrone (E1) and estradiol (E2) throughout life and to evaluate sex-differences using the state-of-the-art liquid chromatography tandem mass spectrometry (LC-MS/MS) method for quantification of E1, E2, and estriol (E3). DESIGN LC-MS/MS method development and construction of estrogen reference ranges. SETTINGS Population-based cross-sectional cohorts from the greater Copenhagen and Aarhus areas. PARTICIPANTS Healthy participants aged 3 months to 61 years (n = 1838). RESULTS An isotope diluted LC-MS/MS method was developed and validated for measurements of serum E1, E2, and E3. Limits of detections (LODs) were 3 pmol/L (E1), 4 pmol/L (E2), and 12 pmol/L (E3), respectively. This sensitive method made it possible to differentiate between male and female concentration levels of E1 and E2 in children. In girls, E2 levels ranged from CONCLUSION Reference ranges of simultaneous quantification of E1 and E2 by this novel specific and highly sensitive LC-MS/MS method provide an invaluable tool in clinical practice and in future research studies.
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Affiliation(s)
- Hanne Frederiksen
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), University of Copenhagen, Copenhagen, Denmark
| | - Trine Holm Johannsen
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), University of Copenhagen, Copenhagen, Denmark
| | - Stine Ehlern Andersen
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jakob Albrethsen
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), University of Copenhagen, Copenhagen, Denmark
| | | | - Jørgen Holm Petersen
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), University of Copenhagen, Copenhagen, Denmark
- Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark
| | | | | | - Mia Elbek Schorring
- Paediatrics and Adolescent Medicine, Aarhus University Hospital, Aahus, Denmark
| | - Allan Linneberg
- Center for Clinical Research and Disease Prevention, Bispebjerg and Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Katharina M Main
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), University of Copenhagen, Copenhagen, Denmark
| | - Anna-Maria Andersson
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), University of Copenhagen, Copenhagen, Denmark
| | - Anders Juul
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), University of Copenhagen, Copenhagen, Denmark
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Abstract
Rapid advancements in metabolomics technologies have allowed for application of liquid chromatography mass spectrometry (LCMS)-based metabolomics to investigate a wide range of biological questions. In addition to an important role in studies of cellular biochemistry and biomarker discovery, an exciting application of metabolomics is the elucidation of mechanisms of drug action (Creek et al., Antimicrob Agents Chemother 60:6650-6663, 2016; Allman et al., Antimicrob Agents Chemother 60:6635-6649, 2016). Although it is a very useful technique, challenges in raw data processing, extracting useful information out of large noisy datasets, and identifying metabolites with confidence, have meant that metabolomics is still perceived as a highly specialized technology. As a result, metabolomics has not yet achieved the anticipated extent of uptake in laboratories around the world as genomics or transcriptomics. With a view to bring metabolomics within reach of a nonspecialist scientist, here we describe a routine workflow with IDEOM, which is a graphical user interface within Microsoft Excel, which almost all researchers are familiar with. IDEOM consists of custom built algorithms that allow LCMS data processing, automatic noise filtering and identification of metabolite features (Creek et al., Bioinformatics 28:1048-1049, 2012). Its automated interface incorporates advanced LCMS data processing tools, mzMatch and XCMS, and requires R for complete functionality. IDEOM is freely available for all researchers and this chapter will focus on describing the IDEOM workflow for the nonspecialist researcher in the context of studies designed to elucidate mechanisms of drug action.
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Affiliation(s)
- Anubhav Srivastava
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Darren J Creek
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia.
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Wang X, Shen S, Rasam SS, Qu J. MS1 ion current-based quantitative proteomics: A promising solution for reliable analysis of large biological cohorts. Mass Spectrom Rev 2019; 38:461-482. [PMID: 30920002 PMCID: PMC6849792 DOI: 10.1002/mas.21595] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 02/28/2019] [Indexed: 05/04/2023]
Abstract
The rapidly-advancing field of pharmaceutical and clinical research calls for systematic, molecular-level characterization of complex biological systems. To this end, quantitative proteomics represents a powerful tool but an optimal solution for reliable large-cohort proteomics analysis, as frequently involved in pharmaceutical/clinical investigations, is urgently needed. Large-cohort analysis remains challenging owing to the deteriorating quantitative quality and snowballing missing data and false-positive discovery of altered proteins when sample size increases. MS1 ion current-based methods, which have become an important class of label-free quantification techniques during the past decade, show considerable potential to achieve reproducible protein measurements in large cohorts with high quantitative accuracy/precision. Nonetheless, in order to fully unleash this potential, several critical prerequisites should be met. Here we provide an overview of the rationale of MS1-based strategies and then important considerations for experimental and data processing techniques, with the emphasis on (i) efficient and reproducible sample preparation and LC separation; (ii) sensitive, selective and high-resolution MS detection; iii)accurate chromatographic alignment; (iv) sensitive and selective generation of quantitative features; and (v) optimal post-feature-generation data quality control. Prominent technical developments in these aspects are discussed. Finally, we reviewed applications of MS1-based strategy in disease mechanism studies, biomarker discovery, and pharmaceutical investigations.
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Affiliation(s)
- Xue Wang
- Department of Cell Stress BiologyRoswell Park Cancer InstituteBuffaloNew York
| | - Shichen Shen
- Department of Pharmaceutical SciencesUniversity at BuffaloState University of New YorkNew YorkNew York
| | - Sailee Suryakant Rasam
- Department of Biochemistry, University at BuffaloState University of New YorkNew YorkNew York
| | - Jun Qu
- Department of Cell Stress BiologyRoswell Park Cancer InstituteBuffaloNew York
- Department of Pharmaceutical SciencesUniversity at BuffaloState University of New YorkNew YorkNew York
- Department of Biochemistry, University at BuffaloState University of New YorkNew YorkNew York
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6
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Monostori P, Klinke G, Hauke J, Richter S, Bierau J, Garbade SF, Hoffmann GF, Langhans CD, Haas D, Okun JG. Extended diagnosis of purine and pyrimidine disorders from urine: LC MS/MS assay development and clinical validation. PLoS One 2019; 14:e0212458. [PMID: 30817767 PMCID: PMC6394934 DOI: 10.1371/journal.pone.0212458] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 02/01/2019] [Indexed: 12/31/2022] Open
Abstract
Background and aims Inborn errors of purine and pyrimidine metabolism are a diverse group of disorders with possible serious or life-threatening symptoms. They may be associated with neurological symptoms, renal stone disease or immunodeficiency. However, the clinical presentation can be nonspecific and mild so that a number of cases may be missed. Previously published assays lacked detection of certain diagnostically important biomarkers, including SAICAr, AICAr, beta-ureidoisobutyric acid, 2,8-dihydroxyadenine and orotidine, necessitating the use of separate assays for their detection. Moreover, the limited sensitivity for some analytes in earlier assays may have hampered the reliable detection of mild cases. Therefore, we aimed to develop a liquid chromatography–tandem mass spectrometry (LC-MS/MS) assay that allows the simultaneous and sensitive detection of an extended range of purine and pyrimidine biomarkers in urine. Methods The assay was developed and validated using LC-MS/MS and clinically tested by analyzing ERNDIM Diagnostic Proficiency Testing (DPT) samples and further specimens from patients with various purine and pyrimidine disorders. Results Reliable determination of 27 analytes including SAICAr, AICAr, beta-ureidoisobutyric acid, 2,8-dihydroxyadenine and orotidine was achieved in urine following a simple sample preparation. The method clearly distinguished pathological and normal samples and differentiated between purine and pyrimidine defects in all clinical specimens. Conclusions A LC-MS/MS assay allowing the simultaneous, sensitive and reliable diagnosis of an extended range of purine and pyrimidine disorders has been developed. The validated method has successfully been tested using ERNDIM Diagnostic Proficiency Testing (DPT) samples and further clinical specimens from patients with various purine and pyrimidine disorders. Sample preparation is simple and assay duration is short, facilitating an easier inclusion of the assay into the diagnostic procedures.
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Affiliation(s)
- Péter Monostori
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
- * E-mail:
| | - Glynis Klinke
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Jana Hauke
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Sylvia Richter
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Jörgen Bierau
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Sven F. Garbade
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Georg F. Hoffmann
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Claus-Dieter Langhans
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Dorothea Haas
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Jürgen G. Okun
- Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
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Marentes-Culma R, Orduz-Díaz LL, Coy-Barrera E. Targeted Metabolite Profiling-Based Identification of Antifungal 5- n-Alkylresorcinols Occurring in Different Cereals against Fusarium oxysporum. Molecules 2019; 24:molecules24040770. [PMID: 30795501 PMCID: PMC6412215 DOI: 10.3390/molecules24040770] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 02/18/2019] [Accepted: 02/19/2019] [Indexed: 11/16/2022] Open
Abstract
A rapid and convenient biochemometrics-based analysis of several cereal-derived extracts was used to identify n-alkyl(enyl)resorcinols (AR) as antifungals against Fusarium oxysporum. Total AR content and liquid chromatography/mass spectrometry (LC-MS)-based profiles were recorded for each extract, in addition to their antifungal activity, to help integrate these chemical and biological datasets by orthogonal partial least squares regression. In this study, we developed and used a micro-scale amended medium (MSAM) assay to evaluate the in vitro mycelial growth inhibition at low amounts of extracts. Triticale husk-derived extracts had the highest AR content (662.1 µg olivetol equivalent/g dry extract), exhibiting >79% inhibition at the highest doses (10.0–1.0 µg/µL). Correlation of the chemical and antifungal datasets using supervised metabolite profiling revealed that 5-n-nonadecanylresorcinol, 5-n-heneicosylresorcinol, and 5-n-tricosyl-resorcinol were the most active ARs occurring in cereal products from Colombia. Hence, we propose the biochemometrics-based approach as a useful tool for identifying AR-like antifungals against F. oxysporum.
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Affiliation(s)
- Ronald Marentes-Culma
- Laboratorio de Química Bioorgánica, Universidad Militar Nueva Granada, Cajicá 250247, Colombia.
| | - Luisa L Orduz-Díaz
- Laboratorio de Química Bioorgánica, Universidad Militar Nueva Granada, Cajicá 250247, Colombia.
| | - Ericsson Coy-Barrera
- Laboratorio de Química Bioorgánica, Universidad Militar Nueva Granada, Cajicá 250247, Colombia.
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Raju KSR, Gundeti M, Malik MY, Kadian N, Rashid M, Taneja I, Singh SP, Wahajuddin M. Bioanalysis of antitubercular drugs using liquid chromatography. J Pharm Biomed Anal 2016; 134:295-309. [PMID: 27951471 DOI: 10.1016/j.jpba.2016.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 11/01/2016] [Accepted: 11/08/2016] [Indexed: 11/17/2022]
Abstract
Tuberculosis is a life threatening disease and second to HIV in terms of deaths due to infectious diseases. Drug resistance development of the first-line drugs is a major concern in the treatment of this disease. There is no comprehensive and critical review in the literature of the bioanalytical methods for the determination of anti-tubercular agents from last two decades. This work offers a detailed account on the liquid chromatographic methods reported in the literature for the estimation of various anti-tubercular drugs. Major emphasis is given to sample preparation process, sensitivity of method, chromatographic separation conditions and detection systems used in their bioanalysis.
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Affiliation(s)
- Kanumuri Siva Rama Raju
- Academy of Scientific and Innovative Research, New Delhi, India; Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Manoj Gundeti
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research, Raebareli, India
| | - Mohd Yaseen Malik
- Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Naveen Kadian
- Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Mamunur Rashid
- Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Isha Taneja
- Academy of Scientific and Innovative Research, New Delhi, India; Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow, India
| | | | - Muhammad Wahajuddin
- Academy of Scientific and Innovative Research, New Delhi, India; Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow, India; Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research, Raebareli, India.
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9
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Abstract
Evolution in preparation of chromatographic columns has created the need for studying and evaluating them with the use of smart software. This research is an attempt to compare the retention mechanism between two stationary phases (butyl and phenyl) with the use of multivariate analysis for a large number of probes. Partial least squares has the ability to spot either major or minor differences in the chromatographic behavior of probes, with regard to changes in the stationary or mobile phases. The models developed refer to a total of 108 miscellaneous chemical compounds, described by 63 X variables (physicochemical properties and structural features) and one Y variable (retention time). The results showed that in both columns and mobile phases (40% methanol or 40% acetonitrile) the retention of an analyte is mainly affected by its lipophilicity, molar volume, and refractivity, which tend to cause delayed elution. On the contrary, solubility in water, polar surface area, and hydrogen bond donor or acceptor properties promote faster elution. The most important difference proved to be the effect of the presence of the carboxylic group and the solubility that affected the retention in a similar way in both columns but not with both mobile phases.
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Affiliation(s)
- Maria G Kouskoura
- Aristotle University of Thessaloniki, Laboratory of Pharmaceutical Analysis, Department of Pharmaceutical Technology, School of Pharmacy, Faculty of Health Sciences, 54124 Thessaloniki, Greece
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10
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Bártl J, Chrastina P, Krijt J, Hodík J, Pešková K, Kožich V. Simultaneous determination of cystathionine, total homocysteine, and methionine in dried blood spots by liquid chromatography/tandem mass spectrometry and its utility for the management of patients with homocystinuria. Clin Chim Acta 2014; 437:211-7. [PMID: 25086281 DOI: 10.1016/j.cca.2014.07.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 07/08/2014] [Accepted: 07/22/2014] [Indexed: 11/20/2022]
Abstract
BACKGROUND Disorders of homocysteine and B-vitamin metabolism represent a significant problem in clinical practice. Establishing the diagnosis requires specialized tests with demanding preanalytical requirements. To advance the detection of patients with these disorders, we developed a method for the simultaneous determination of cystathionine (Cysta), methionine (Met) and total homocysteine (tHcy) in dried blood spots (DBSs). METHODS A punch from a DBS sample was mixed with a solution of isotopically labeled internal standards, and analytes were extracted using methanol/0.1% formic acid/0.5mol/L dithiothreitol. The extract was injected into an LC-MS/MS system operating in MRM mode. RESULTS The analytical performance of the method employing DBS is adequate for its purpose and the type of sample. Compared with Cysta, tHcy and Met plasma levels, our method exhibited a negative bias between -3.8% and -42.2% due to the lower concentrations of these analytes in erythrocytes. The tHcy level and the Met/Cysta ratio in DBS enabled the clear detection of 12 patients with disorders of transsulfuration and with genetic and nutritional remethylation defects. CONCLUSIONS The ease of collecting and transporting DBS samples may advance diagnostic procedures in patients with neuropsychiatric disorders and thromboembolism. Consequently, this approach may facilitate detection and simplify the monitoring of patients with homocystinuria.
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Affiliation(s)
- Josef Bártl
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Czech Republic
| | - Petr Chrastina
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Czech Republic
| | - Jakub Krijt
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Czech Republic
| | - Jakub Hodík
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Czech Republic
| | - Karolína Pešková
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Czech Republic
| | - Viktor Kožich
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Czech Republic.
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11
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Gathungu RM, Flarakos CC, Reddy GS, Vouros P. The role of mass spectrometry in the analysis of vitamin D compounds. Mass Spectrom Rev 2013; 32:72-86. [PMID: 22996283 DOI: 10.1002/mas.21353] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 04/03/2012] [Accepted: 04/03/2012] [Indexed: 06/01/2023]
Abstract
This review highlights the superseding role of mass spectrometry in the structural characterization and quantitation of vitamin D compounds in comparison to other analytical methods (e.g., UV, bioassays) that lack the sensitivity and specificity of mass spectrometry. After a short introduction to the biochemistry of vitamin D compounds, an overview of the current techniques to characterize and quantitate vitamin D compounds is given with emphasis on the contribution of mass spectrometry.
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Affiliation(s)
- Rose M Gathungu
- Barnett Institute of Chemical and Biological Analysis, Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, USA
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12
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Abstract
Recently, interest in untargeted metabolomics has become prevalent in the general scientific community among an increasing number of investigators. The majority of these investigators, however, do not have the bioinformatic expertise that has been required to process metabolomic data by using command-line driven software programs. Here we introduce a novel platform to process untargeted metabolomic data that uses an intuitive graphical interface and does not require installation or technical expertise. This platform, called XCMS Online, is a web-based version of the widely used XCMS software that allows users to easily upload and process liquid chromatography/mass spectrometry data with only a few mouse clicks. XCMS Online provides a solution for the complete untargeted metabolomic workflow including feature detection, retention time correction, alignment, annotation, statistical analysis, and data visualization. Results can be browsed online in an interactive, customizable table showing statistics, chromatograms, and putative METLIN identities for each metabolite. Additionally, all results and images can be downloaded as zip files for offline analysis and publication. XCMS Online is available at https://xcmsonline.scripps.edu.
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Affiliation(s)
- Ralf Tautenhahn
- Department of Chemistry and Molecular Biology, Center for Metabolomics, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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13
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Abou-Diwan C. LC-MS/MS in the clinical lab: strengths, applications, challenges. MLO Med Lab Obs 2011; 43:20-24. [PMID: 21882756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Affiliation(s)
- Charbel Abou-Diwan
- Department of Pathology, Emory University School of Medicine, Atlanta, GA, USA
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14
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Mikel C, Pesce A, West C. A tale of two drug testing technologies: GC-MS and LC-MS/MS. Pain Physician 2010; 13:91-92. [PMID: 20119467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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McDonald M, Malone E, McBride J. Confirmation of hormones in animal serum by liquid chromatography/tandem mass spectrometry according to European Commission Decision 2002/657. J AOAC Int 2010; 93:343-349. [PMID: 20334197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A novel and rapid method was developed and validated for the confirmation of endogenous and synthetic hormones in animal serum using LC/MS/MS. Detection of 17 beta-estradiol and beta-testosterone below the respective European Union-recommended levels of 0.1 and 0.5 microg/L was achieved, as was a required performance level of 0.1 microg/L for 17 alpha-estradiol and 0.5 microg/L for 17 alpha-testosterone, medroxyprogesterone-17-acetate, and progesterone. The method was established with dilution of serum followed by ion-exchange SPE, LC separation and MS detection with electrospray ionization, selected reaction monitoring, and positivelnegative switching. Two characteristic transitions were monitored for each analyte. The method was applied to bovine, ovine, porcine, equine, and avian samples and validated according to European Commission Decision 2002/657/EC and accepted for ISO/IEC 17025:2005 accreditation. An extended calibration curve allows naturally occurring levels of endogenous hormones to be quantified. Recoveries ranged from 97.3% for 17 alpha-testosterone to 102.0% for 17 alpha-estradiol. The decision limit CCalpha ranged from 0.02 microg/L for 17 alpha- and beta-estradiol to 0.12 microg/L for progesterone. Detection capability CCbeta ranged from 0.03 microg/L for 17 a-estradiol to 0.20 microg/L for progesterone.
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Affiliation(s)
- Mark McDonald
- Central Meat Control Laboratory, Department of Agriculture, Backweston Campus, Celbridge, Co. Kildare, Republic of Ireland.
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16
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West R, Pesce A, West C, Crews B, Mikel C, Almazan P, Rosenthal M, Latyshev S. Comparison of clonazepam compliance by measurement of urinary concentration by immunoassay and LC-MS/MS in pain management population. Pain Physician 2010; 13:71-78. [PMID: 20119465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
BACKGROUND Physicians determine patient compliance with their medications by use of urine drug testing. It is known that measurement of benzodiazepines is limited by immunoassay specificity and cutoff limits and therefore does not offer physicians an accurate picture of their patients' compliance with these medications. A few studies have used lower cutoffs to demonstrate patient compliance. OBJECTIVES To define more appropriate cutoffs for compliance monitoring of patients prescribed clonazepam as determined using immunoassay and liquid chromatography-tandem mass spectrometry (LC-MS/MS). STUDY DESIGN A diagnostic accuracy study of the urinary excretion of clonazepam. METHODS Millennium Laboratories performed measurements on the urinary excretion of pain patients prescribed clonazepam as the indicator test. This benzodiazepine was chosen because it forms one major metabolite, 7-aminoclonazepam which is specific for that drug. Patients whose only benzodiazepine medication was clonazepam were selected as the test population. The Millennium Laboratories test database was filtered first to select patients on clonazepam, then a second filter was used to eliminate patients with any other listed benzodiazepine medications. Samples were tested using the Microgenics DRI benzodiazepine assay with a 200 ng/mL cutoff. The same samples were quantitatively assessed for 7-aminoclonazepam by LC-MS/MS with a cutoff of 40 ng/mL. The results from the immunoassay were scored as positive or negative while the quantitative results from the LC-MS/MS were also scored as positive or negative depending upon their concentration. RESULTS Samples from 180 patients met these medication criteria. The positivity rates were 21% (38 samples) by immunoassay. The positivity rate was 70% (126 samples) if the LC-MS/MS cutoff was set at 200 ng/mL. However, the positivity rate was 87% (157 samples) if the LC-MS/MS was set at 40 ng/mL. Concentration distributions revealed a significant fraction (7%) in the 40 - 100 ng/mL range. LIMITATIONS A limitation of the study was the inability to measure lower than 40 ng/mL. There may be another fraction of the population that was positive below the cutoff value. CONCLUSIONS The difference in positivity rate between the immunoassay and the LC-MS/MS result showed that the nominal 200 ng/mL cutoff of the immunoassay did not apply to 7-aminoclonazepam. This low immunoassay positivity rate is inconsistent with the manufacturer's published cross reactivity data for clonazepam and 7-aminoclonazepam. These data illustrate the limitations of using a 200 ng/mL cutoff to monitor clonazepam compliance and suggest that a cutoff of 40 ng/mL or less is needed to reliably monitor use of this drug.
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Affiliation(s)
- Robert West
- Millennium Laboratories Research Institute, San Diego, CA 92127, USA.
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17
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Qiao YL, Zhang YH, Zhang W, Zhang JL. A rapid resolution liquid chromatographic method for fingerprint analysis of raw and processed caowu (Aconitum kusnezoffii). J AOAC Int 2009; 92:653-662. [PMID: 19485227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A sensitive and reliable rapid resolution liquid chromatographic (RRLC) method coupled with diode array detection has been developed for the fingerprint analysis of raw and processed caowu (Aconitum kusnezoffii). The RRLC fingerprints were established with a Zorbax Extend C18 analytical column (4.6 x 50 mm, 1.8 microm) and gradient elution. Analysis run time was <10 min. The method displayed good precision, stability, and repeatability in fingerprint analysis. Characteristic RRLC fingerprints of caowu were generated and used to assess the consistency and differences in the products. Raw and processed caowu from different sources were analyzed under the developed RRLC conditions, yielding contrasting RRLC fingerprints. Comparison of the RRLC fingerprints of processed and raw caowu indicated that the major constituents changed during processing. Meanwhile, a peak area ratio analysis method was applied to assess their chromatographic fingerprints. In characterizing the constituents of caowu, 11 major chromatographic peaks were identified by mass spectrometry and compared with reference standards and reference data. In summary, RRLC fingerprinting is a rapid and useful way to evaluate the quality of raw and processed caowu.
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Affiliation(s)
- Yan-Ling Qiao
- Chinese Academy of Medical Sciences & Peking Union Medical College, Institute of Materia Medica, Beijing 100050, People's Republic of China
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18
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Avula B, Wang YH, Smillie TJ, Khan IA. Column liquid chromatography/electrospray ionization-time of flight-mass spectrometry and ultraperformance column liquid chromatography/mass spectrometry methods for the determination of ginkgolides and bilobalide in the leaves of Ginkgo biloba and dietary supplements. J AOAC Int 2009; 92:645-652. [PMID: 19485226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Column liquid chromatography/electrospray ionization-time of flight-mass spectrometry (LC/ESI-TOF-MS) and ultraperformance column liquid chromatographiclMS (UPLC/MS) methods were developed for the determination of 5 terpenelactones in the leaves of Ginkgo biloba. The separation was performed using a C18 column and a mobile phase composed of water and acetonitrile. The limit of detection (LOD) values for ginkgolide J, ginkgolide C, ginkgolide B, and ginkgolide A were found to be in the range of 1-10 ng/mL by both methods, and the bilobalide LOD was 200 ng/mL by LC/ESI-TOF and 35 ng/mL by UPLC/MS. Using the optimized method, 4 commercial products were analyzed. Concentrations of total marker compounds in these products were in the 0.09-15.4% range, with individual ginkgo terpenelactones being detected at ppb levels. LC/MS with ESI is described for the identification and quantification of ginkgolides and bilobalide in plant samples and dietary supplements that claim to contain G. biloba. These methods involve the use of the [M + NH4]+ and [M + H]+ ions of sesquiterpenoids in the positive ion mode with extractive ion monitoring by LC/ESI-TOF-MS and selected ion monitoring by UPLC/MS. The LC method coupled with MS analysis yielded well-separated peaks which resulted in a clear identification of the compounds.
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Affiliation(s)
- Bharathi Avula
- The University of Mississippi, Research Institute of Pharmaceutical Sciences, National Center for Natural Products Research, MS 38677, USA
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19
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Qiao YL, Sheng YX, Wang LQ, Zhang JL. Development of a rapid resolution liquid chromatographic method for simultaneous analysis of four alkaloids in Rhizoma coptidis under different cultivation conditions. J AOAC Int 2009; 92:663-671. [PMID: 19485228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A sensitive and specific method using rapid resolution liquid chromatography coupled with UV-Vis detection was developed for fingerprint analysis of Rhizoma coptidis and simultaneous determination of 4 alkaloids: jatrorrhizine, coptisine, palmatine, and berberine. Samples of R. coptidis grown under different cultivation conditions and from different habitats were analyzed. The analysis was performed using a reversed-phase octylsilyl (C8) column and gradient elution. The mobile phase consisted of acetonitrile and 20 mmol/L KH2PO4. Each analysis was completed within 3.5 min. The method showed good linearity within test ranges of 4.75-47.50 microg/mL for jatrorrhizine, 20.60-164.80 microg/mL for coptisine, 18.07-180.73 microg/mL for palmatine, and 89.70-717.57 microg/mL for berberine. The method showed good precision, repeatability, and stability for quantification of the 4 alkaloids. The lower limit of detection was 0.19 ng for jatrorrhizine, 0.21 ng for coptisine, 0.15 ng for palmatine, and 0.14 ng for berberine. The lower limit of quantification was 0.57 ng for jatrorrhizine, 0.82 ng for coptisine, 0.55 ng for palmatine, and 0.27 ng for berberine. The overall recovery ranged from 96.30 to 104.10% for the 4 alkaloids. The method is accurate, rapid, and convenient, and it is suitable for routine quality control of R. coptidis.
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Affiliation(s)
- Yan-Ling Qiao
- Chinese Academy of Medical Sciences & Peking Union Medical College, Institute of Materia Medica, Beijing 100050, People's Republic of China
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20
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Sun H, Wang F, Ai L, Guo C, Chen R. Validated method for determination of eight banned nitroimidazole residues in natural casings by LC/MS/MS with solid-phase extraction. J AOAC Int 2009; 92:612-621. [PMID: 19485222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A sensitive method based on solid-phase extraction-liquid chromatography-tandem mass spectrometry interfaced with electrospray ionization (SPE-LC-MS/MS-ESI) was developed for the simultaneous determination of 8 banned nitroimidazole (NOZ) drugs including metronidazole (MNZ), ronidazole (RNZ), dimetridazole (DMZ), tinidazole, ornidazole, secnidazole, metronidazole-OH (MNZOH, the metabolite of MNZ), and 2-hydroxymethyl-1-methyl-5-nitroimidazole (HMMNI, the metabolite of RNZ and DMZ) in natural casings. After extraction with ethyl acetate and evaporation, the NOZs were reconstituted in ethyl acetate and purified on a strong cation-exchange SPE column, and then LC/MS/MS analysis was performed by positive ESI applying multiple reaction monitoring of 2 transition reactions for each compound. The method was validated according to the European Union requirements (Commission Decision 2002/657/EC). Specificity, linearity, decision limit (CCalpha), detection capability (CCbeta), accuracy, and precision were determined. Average recoveries of the 8 NOZs from natural animal casing fortified at 3 levels (0.1, 0.5, and 1 microg/kg) ranged from 87.3 to 116.5%. The calculated CCalpha for NOZs ranged from 0.029 to 0.049 microg/kg, and CCbeta ranged from 0.049 to 0.083 microg/kg. Repeatability was in the range of 3.35-10.1%, and within-laboratory reproducibility was <10.3%.
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Affiliation(s)
- Hanwen Sun
- Hebei University, College of Chemistry and Environmental Science, Key Laboratory of Analytical Science and Technology of Hebei Province, Baoding, 071002, People's Republic of China.
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21
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Lai L, Liu Y, Hao H, Wang G, Chen X, Ren H. Determination of 20(S)-ginsenoside Rh1 and its aglycone 20(S)-protopanaxatriol in rat plasma by sensitive LC-APCI-MS method and its application to pharmacokinetic study. Eur J Mass Spectrom (Chichester) 2009; 15:57-65. [PMID: 19174594 DOI: 10.1255/ejms.974] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) method has been developed for the measurement of the concentrations of 20(S)-ginsenoside Rh1 and its aglycone 20(S)-protopanaxatriol in rat plasma with panaxatriol as internal standard. The method involved single liquid-liquid extraction of both 20(S)-ginsenoside Rh1 and 20(S)-protopanaxatriol from plasma samples with n-butanol. The limit of quantification (LOQ) was 5 ng mL(-1) for both compounds. The method was validated within the linear range 5-2000 ng.mL(-1) for both compounds. The correlation coefficient for the calibration regression line was 0.999 or better. Intra-day and inter-day accuracy were better than 15%. The method has been successfully used for the pharmacokinetic studies in rats. After intravenous administrations, the mean retention times of 20(S)-ginsenoside Rh1 and 20(S)-protopanaxatriol were 17.1 +/- 2.0 min and 3.46 +/- 0.33 h, respectively.
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Affiliation(s)
- Li Lai
- Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
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22
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Mistri HN, Jangid AG, Shrivastav P. Sensitive and rapid method to determine trimetazidine in human plasma by liquid chromatography/tandem mass spectrometry. J AOAC Int 2008; 91:562-571. [PMID: 18567302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A simple, sensitive, and rapid liquid chromatographic/tandem mass spectrometric (LC/MS/MS) method, using electrospray ionization, was developed and validated to quantify trimetazidine in human plasma using propranolol hydrochloride as an internal standard (IS). Samples were prepared by solid-phase extraction and analyzed without drying and reconstitution. The analyte and IS were chromatographed on a C18 reversed-phase column under isocratic conditions using 2 mM ammonium acetate (pH 3.5)-acetonitrile (40 + 60, v/v) as the mobile phase with a run time of 2.0 min. Quantitation was done on a triple-quadrupole mass analyzer API-3000, equipped with turbo ion spray interface and operating in multiple reaction monitoring mode to detect parent --> product ion (m/z 267.2 --> 181.4) transition. The method was validated for sensitivity, accuracy and precision, linearity, recovery, matrix effect, and stability. Linearity in plasma was observed over the concentration range of 1.5-300 ng/mL. Lower limit of quantification achieved was 1.5 ng/mL with precision < 10% using 10 microL injection volume. The mean relative recovery of analyte (97.36%) and IS (99.93%) was consistent and reproducible. Interbatch and intrabatch precision was < 8.0% and the accuracy determined was within +/- 8% in terms of relative error.
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Affiliation(s)
- Hiren N Mistri
- Gujarat University, Department of Chemistry, School of Sciences, Navrangpura, Ahmedabad 380 009, India
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23
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Rourke WA, Murphy CJ, Pitcher G, van de Riet JM, Burns BG, Thomas KM, Quilliam MA. Rapid postcolumn methodology for determination of paralytic shellfish toxins in shellfish tissue. J AOAC Int 2008; 91:589-597. [PMID: 18567305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A rapid liquid chromatographic (LC) method with postcolumn oxidation and fluorescence detection (excitation 330 nm, emission 390 nm) for the determination of paralytic shellfish toxins (PSTs) in shellfish tissue has been developed. Extracts prepared for mouse bioassay (MBA) were treated with trichloroacetic acid to precipitate protein, centrifuged, and pH-adjusted for LC analysis. Saxitoxin (STX), neoSTX (NEO), decarbamoylSTX (dcSTX), and the gonyautoxins, GTX1, GTX2, GTX3, GTX4, GTX5, dcGTX2, and dcGTX3, were separated on a polar-linked alkyl reversed-phase column using a step gradient elution; the N-sulfocarbamoyl GTXs, C1, C2, C3, and C4, were determined on a C-8 reversed-phase column in the isocratic mode. Relative toxicities were used to determine STX-dihydrochloride salt (diHCl) equivalents (STXeq). Calibration graphs were linear for all toxins studied with STX showing a correlation coefficient of 0.999 and linearity between 0.18 and 5.9 ng STX-diHCI injected (equivalent to 3.9-128 microg STXeq/100 g in tissue). Detection limits for individual toxins ranged from 0.07 microg STXeq/100 g for C1 and C3 to 4.1 microg STXeq/100 g for GTX1. Spike recoveries ranged from 76 to 112% in mussel tissue. The relative standard deviation (RSD) of repeated injections of GTX and STX working standard solutions was < 4%. Uncertainty of measurement at a level of 195 microg STXeq/100 g was 9%, and within-laboratory reproducibility expressed as RSD was 4.6% using the same material. Repeatability of a 65 microg STXeq/100 g sample was 3.0% RSD. Seventy-three samples were analyzed by the new postcolumn method and both AOAC Official Methods for PST determination: the MBA (y = 1.22x + 13.99, r2 = 0.86) and the precolumn LC oxidation method of Lawrence (y = 2.06x + 12.21, r2 = 0.82).
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Affiliation(s)
- Wade A Rourke
- Canadian Food Inspection Agency, Dartmouth Laboratory, 1992 Agency Dr, Dartmouth, Nova Scotia, B3B 1Y9, Canada.
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Senyuva HZ, Ozcan S, Cimen D, Gilbert J. Determination of fumonisins B1 and B2 in corn by liquid chromatography/mass spectrometry with immunoaffinity column cleanup: single-laboratory method validation. J AOAC Int 2008; 91:598-606. [PMID: 18567306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A single-laboratory method validation was conducted to establish the effectiveness of an immunoaffinity column cleanup procedure followed by liquid chromatography/mass spectrometry (LCIMS) for the determination of fumonisins B1 and B2 (FBI + FB2) in corn. The test portion is extracted with acetonitrile-methanol-water (25 + 25 + 50). The extract is filtered, diluted with phosphate-buffered saline solution, and applied to an immunoaffinity column. FB1 + FB2 are removed with methanol and directly determined by reversed-phase LC with MS detection using selected-ion monitoring of 2 characteristic ions in each case. Test portions of blank corn samples were spiked with a mixture of FB1 + FB2 to give total levels of 200 and 500 ng/g, respectively. Recoveries of both FB1 and FB2 from spiked samples averaged 90.4-101%. Based on results for spiked raw corn (triplicates at 2 levels), the relative standard deviation for repeatability ranged from 2.8 to 7.1%. The accuracy of the method was demonstrated by analysis of Food Analysis Performance Assessment Scheme (FAPAS) test material. The method was also applied to a small survey of processed corn products such as corn chips, cornflakes, and popcorn.
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Affiliation(s)
- Hamide Z Senyuva
- TUBITAK, Ankara Test and Analysis Laboratory (ATAL), Konya Yolu No. 67, Besevler, 06530, Ankara, Turkey.
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Fu B, Wang J, Roturier JM, Tang Z, Li H, Wei G. Determination of total dietary fiber in selected foods containing resistant maltodextrin by a simplified enzymatic-gravimetric method and liquid chromatography: interlaboratory study in China. J AOAC Int 2008; 91:614-621. [PMID: 18567308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
An interlaboratory study was conducted in China to validate the modified AOAC Official Method 2001.03 for the determination of total dietary fiber (TDF) in foods containing resistant maltodextrin (RMD), which will be adopted as the National Standard Method of China. The kind of buffer solution, the volume of filtrate evaporation, the volume of eluent for desalting and residual solution after evaporation, etc. were modified, which had been proved to have acceptable accuracy and precision in the routine assay. TDF contents in 3 representative foods and 2 kinds of RMD ingredient (i.e., NUTRIOSE 06 and NUTRIOSE 10) were measured using the modified method in 6 eligible laboratories representing commercial, industrial, and governmental laboratories in China. The results of the interlaboratory study indicated that the intralaboratory repeatability, interlaboratory reproducibility, and precision of the modified method are adequate for reliable analysis of TDF in food containing RMD, as well as resistant dextrin. Compared to AOAC Official Method 2001.03, the modified method is time- and cost-saving.
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Affiliation(s)
- Boqiang Fu
- National Institute of Metrology, Division of Biological, Energy and Environment Measurement, Beijing, 100013, People's Republic of China.
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26
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de Groot JCW, Fiers MWEJ, van Ham RCHJ, America AHP. Post alignment clustering procedure for comparative quantitative proteomics LC-MS data. Proteomics 2008; 8:32-6. [PMID: 18095361 DOI: 10.1002/pmic.200700707] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Indexed: 12/16/2023]
Abstract
Comparative LC-MS is a powerful method for detailed quantitative comparison of complex protein mixtures. Dedicated software is required for detection, matching, and alignment of peaks in multiple LC-MS datasets. However, retention time shifts, saturation effects, limitations of experimental accuracy, and possible occurrence of split peaks make it difficult for software to perfectly match all chromatograms. We describe a procedure to assess the above problems and show that dataset quality can be enhanced with the aid of cluster analysis.
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Affiliation(s)
- Joost C W de Groot
- Plant Research International, Wageningen-UR, Wageningen, The Netherlands
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Cho H, Smalley DM, Theodorescu D, Ley K, Lee JK. Statistical identification of differentially labeled peptides from liquid chromatography tandem mass spectrometry. Proteomics 2007; 7:3681-92. [PMID: 17879999 DOI: 10.1002/pmic.200601034] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
LC-MS/MS with certain labeling techniques such as isotope-coded affinity tag (ICAT) enables quantitative analysis of paired protein samples. However, current identification and quantification of differentially expressed peptides (and proteins) are not reliable for large proteomics screening of complex biological samples. The number of replicates is often limited because of the high cost of experiments and the limited supply of samples. Traditionally, a simple fold change cutoff is used, which results in a high rate of false positives. Standard statistical methods such as the two-sample t-test are unreliable and severely underpowered due to high variability in LC-MS/MS data, especially when only a small number of replicates are available. Using an advanced error pooling technique, we propose a novel statistical method that can reliably identify differentially expressed proteins while maintaining a high sensitivity, particularly with a small number of replicates. The proposed method was applied both to an extensive simulation study and a proteomics comparison between microparticles (MPs) generated from platelet (platelet MPs) and MPs isolated from plasma (plasma MPs). In these studies, we show a significant improvement of our statistical analysis in the identification of proteins that are differentially expressed but not detected by other statistical methods. In particular, several important proteins - two peptides for beta-globin and three peptides for von Willebrand Factor (vWF) - were identified with very small false discovery rates (FDRs) by our method, while none was significant when other conventional methods were used. These proteins have been reported with their important roles in microparticles in human blood cells: vWF is a platelet and endothelial cell product that binds to P-selectin, GP1b, and GP IIb/IIIa, and beta-globin is one of the peptides of hemoglobin involved in the transportation of oxygen by red blood cells.
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Affiliation(s)
- Hyungjun Cho
- Department of Statistics, Korea University, Seoul, Korea
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Nyangoma SO, van Kampen AAHC, Reijmers TH, Govorukhina NI, van der Zee AGJ, Billingham LJ, Bischoff R, Jansen RC. Multiple testing issues in discriminating compound-related peaks and chromatograms from high frequency noise, spikes and solvent-based noise in LC-MS data sets. Stat Appl Genet Mol Biol 2007; 6:Article23. [PMID: 17910529 DOI: 10.2202/1544-6115.1295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Liquid Chromatography--Mass Spectrometry (LC-MS) is a powerful method for sensitive detection and quantification of proteins and peptides in complex biological fluids like serum. LC-MS produces complex data sets, consisting of some hundreds of millions of data points per sample at a resolution of 0.1 amu in the m/z domain and 7000 data points in the time domain. However, the detection of the lower abundance proteins from this data is hampered by the presence of artefacts, such as high frequency noise and spikes. Moreover, not all of the tens of thousands of the chromatograms produced per sample are relevant for the pursuit of the biomarkers. Thus in analysing the LC-MS data, two critical pre-processing issues arise. Which of the thousands of the: 1. chromatograms per sample are relevant for the detection of the biomarkers?, and 2. signals per chromatogram are truly compound-related? Each of these issues involves assessing the significance (deviation from noise) of multiple observations and the issue of multiple comparisons arises. Current methods disregard the multiplicity and provide no concrete threshold for significance. However, with such procedures, the probability of one or more false-positives is high as the number of tests to be performed is large, and must be controlled. Realizing that the cut-offs for declaring a chromatogram (or a signal) to be compound-related can hugely influence which proteins are detected, it seems natural to define thresholds that are neither arbitrary nor subjective. We suggest the choice of thresholds guided by the critical aim of controlling the False Discovery Rate (FDR) in multiple hypotheses testing for significance over a large set of features produced per sample. This involves the use of the regression diagnostics to characterize the signals of a chromatogram (e.g. as outliers or influential) and to suggest suitable tests statistics for the multiple testing procedures (MTP) for discriminating noise and spikes from true signals. The role of the Generalized Linear Models (GLM) in this MTP is investigated. The method is applied to LC-MS datasets from trypsin-digested serum spiked with varying levels of horse heart cytochrome C (cytoc).
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Briscoe CJ, Stiles MR, Hage DS. System suitability in bioanalytical LC/MS/MS. J Pharm Biomed Anal 2007; 44:484-91. [PMID: 17433601 DOI: 10.1016/j.jpba.2007.03.003] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2006] [Revised: 03/07/2007] [Accepted: 03/08/2007] [Indexed: 11/25/2022]
Abstract
System suitability is widely recognized as a critical component of bioanalysis. This paper discusses a generic system suitability test that monitors instrument performance throughout a run when used for liquid chromatography tandem mass spectrometry (LC/MS/MS) in bioanalysis. This system suitability process is designed to ensure that the LC/MS/MS system is performing in a manner that leads to the production of accurate and reproducible data that can be submitted with confidence to regulatory agencies. This process contains tests for signal stability, carryover, and instrument response. This approach is integrated throughout an analytical run and has been used in the analysis of over 25,000 batches of clinical samples. Two case studies are presented in which quality control samples and standards meet all acceptance criteria (based on Standard Operating Procedures and the Food and Drug Administration's recommendations for bioanalytical method validation) but failed the proposed system suitability test, and thus were rejected. In these case studies, the concentrations of a significant number of clinical samples (over 35%) were affected, resulting in changes of more than 15% when the samples were reanalyzed. These data indicate that the poor performance of an LC/MS/MS system could adversely affect the calculated concentrations of unknown samples even though the results for quality control samples appear to be acceptable.
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Affiliation(s)
- Chad J Briscoe
- Department of Bioanalysis, MDS Pharma Services, Lincoln, NE 68502, USA.
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30
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Abstract
Statistical properties of the band-broadening function calculated from the equilibrium and kinetic theories of Giddings and Eyring are compared with real liquid-chromatography elution curves of low-molecular-weight substances and with light-scattering elution curves of a high-molecular-weight polystyrene standard injected at several concentrations. The curves obtained by liquid chromatography agree in a large span of elution times with the theoretical ones and can be described by one value of the plate-height. The size exclusion chromatography (SEC) elution curves seem to approach the predicted statistical properties with decreasing concentration of injected polymer but, in general, a reliable prediction of band-broadening (BB) functions in SEC of polymers, especially of non-symmetric BB functions near the exclusion limit, seems not possible at this point. The relation of the theory with the characteristic-function approach developed by Dondi is also discussed.
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Affiliation(s)
- Milos Netopilík
- Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6, Czech Republic.
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31
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Hahn R, Tscheliessnig A, Bauerhansl P, Jungbauer A. Dispersion effects in preparative polymethacrylate monoliths operated in radial-flow columns. ACTA ACUST UNITED AC 2006; 70:87-94. [PMID: 17070924 DOI: 10.1016/j.jbbm.2006.09.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Revised: 09/01/2006] [Accepted: 09/04/2006] [Indexed: 11/17/2022]
Abstract
Monolithic media have found widespread use as excellent tools for fast analytical separations of small molecules, proteins, pDNA and viruses. Polymethacrylate monoliths with large channels are attractive for capturing large molecules, like immunoglobulins, DNA, and viruses. For preparative purposes, these monoliths are operated in radial flow mode. Band spreading in monoliths is extremely low and mostly dominated by the contribution of extra column effects. The model used here had a single axial dispersion coefficient which lumps together extra column effects and the intrinsic band spreading of the monolithic material to characterize the adsorption of proteins and pDNA on polymethacrylate ion-exchange monoliths. Due to the fact that the performance of the monolith was unaffected by the velocity within the applied range, and due to highly favourable adsorption isotherms, a constant pattern model could be applied to predict preparative runs on radial flow units assuming axial flow for modelling.
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Affiliation(s)
- Rainer Hahn
- Department of Biotechnology, University of Natural Resources and Applied Life Sciences Vienna, Muthgasse 18, 1190 Vienna, Austria
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32
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Tozo GCG, Salgado HRN. Determination of lomefloxacin in tablet preparations by liquid chromatography. J AOAC Int 2006; 89:1305-8. [PMID: 17042180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A sensitive, precise, and specific high-performance liquid chromatography (HPLC) method was developed for the assay of lomefloxacin (LFLX) in raw material and tablet preparations. The method validation parameters yielded good results and included the range, linearity, precision, accuracy, specificity, and recovery. It was also found that the excipients in the commercial tablet preparation did not interfere with the assay. The HPLC separation was performed on a reversed-phase Phenomenex C18 column (150 x 4.6 mm id, 5 microm particle size) with a mobile phase composed of 1% acetic acid-acetonitrile-methanol (70 + 15 + 15, v/v/v), pumped isocratically at a flow rate of 1.0 mL/min. The effluent was monitored at 280 nm. The calibration graph for LFLX was linear from 2.0 to 7.0 mg/mL. The interday and intraday precisions (relative standard deviation) were less than 1.0%. The method was applied for the quality control of commercial LFLX tablets to quantitate the drug.
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Affiliation(s)
- Greci C G Tozo
- Faculdade de Ciências Farmacêuticas, Programa de Pòs-Graduaçâo em Ciências Farmacêuticas, UNESP, Araraquara, SP, Brazil
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33
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Campbell H, Nayeri G. Determination of monensin, narasin, and salinomycin in mineral premixes, supplements, and animal feeds by liquid chromatography and post-column derivatization: collaborative study. J AOAC Int 2006; 89:1229-42. [PMID: 17042170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A liquid chromatographic (LC) method for the analysis of monensin, narasin, and salinomycin in mineral premixes, supplements, and complete animal feeds at medicating and trace levels was collaboratively studied. The method uses methanol-water (90 + 10) extraction with mechanical shaking for 1 h, filtration, and dilution if necessary. Determination of the 3 ionophores is by reversed-phase LC using post-column derivatization with vanillin and detection at 520 nm. Suspect positive trace-level products and medicated feeds containing unexpected ionophores are confirmed by hexane extraction or post-column derivatization with dimethylaminobenzaldehyde (DMAB). Twenty-five test samples of medicated feeds, supplements, and mineral and drug premixes, and 9 test samples for trace-level analysis were sent to 11 collaborators in Bulgaria, Czech Republic, Portugal, France, The Netherlands, United States, and Canada. Acceptable results were received from 10 laboratories. For the medicated complete feeds, supplements, and mineral premixes, RSDr values (within-laboratory repeatability) ranged from 2.5 to 5.2%, RSDR values (among-laboratory reproducibility) ranged from 2.7 to 6.8%, and HorRat values ranged from 0.31 to 1.30. For the drug premixes, the result variability was excessive and HorRat values ranged from 2.27 to 14.1. For the trace-level test samples, all laboratories correctly identified the analytes and did not report any false positives. RSDr values ranged from 1.3 to 9.5%, RSDR values ranged from 5.2 to 13.1%, and HorRat values ranged from 0.4 to 0.97.
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Affiliation(s)
- Harold Campbell
- Canadian Food Inspection Agency, Ottawa Laboratory (Carling), Ottawa, ON, Canada.
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Jiang Y, Xu JZ, Shen CY, Ding T, Chen HL, Wu B, Shen WJ. Determination of chloramphenicol in royal jelly by liquid chromatography/tandem mass spectrometry. J AOAC Int 2006; 89:1432-6. [PMID: 17042196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A liquid chromatographic/tandem mass spectrometric method was developed and validated for the determination of chloramphenicol (CAP) in royal jelly. Royal jelly samples were first denatured with lead acetate solution, and the CAP was extracted with solid-phase extraction before separation by liquid chromatography. A triple-quadrupole mass spectrometer operated in the negative electrospray ionization and selected-reaction monitoring mode was used for the detection of CAP. For method validation, royal jelly samples were fortified at CAP levels between 0.1 and 10.0 microg/kg; at these levels, recovery values (internal standard-corrected) ranged from 93.3 to 105.0%, and the within-laboratory reproducibility (relative standard deviation) was < or = 9.1%. The decision limit was 0.07 microg/kg, and the detection capability was 0.1 microg/kg.
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Affiliation(s)
- Yuan Jiang
- Jiangsu Entry-Exit Inspection and Quarantine Bureau, APFIC, Food Laboratory, 99 Zhonghua Rd, Nanjing, People's Republic of China
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35
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Brum L, Fronza M, Ceni DC, Barth T, Dalmora SL. Validation of liquid chromatography and liquid chromatography/tandem mass spectrometry methods for the determination of etoricoxib in pharmaceutical formulations. J AOAC Int 2006; 89:1268-75. [PMID: 17042175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Reversed-phase liquid chromatography (LC) and LC/tandem mass spectrometry (LC/MS/MS) methods were developed and validated for the determination of etoricoxib in pharmaceutical dosage forms. The LC method was performed by reversed-phase chromatography on a Synergi fusion C18 column (150 x 4.6 mm id) maintained at ambient temperature. The mobile phase consisted of 0.01 M phosphoric acid, pH 3.0-acetonitrile (62 + 38, v/v) at a flow rate of 1.0 mL/min, and photodiode array detection at 234 nm was used. The chromatographic separation was obtained within 7.0 min, and calibration curves were linear in the concentration range of 0.02-150 microg/mL. The LC/MS/MS method was performed on a Luna C18 column (50 x 3.0 mm id). The mobile phase consisted of acetonitrile-water (95 + 5)-0.1% acetic acid (90 + 10, v/v). Detection was performed by positive electrospray ionization in the multiple reaction monitoring mode, monitoring the transitions 359.3 > 280.0 and 332.0 > 95.0 for etoricoxib and piroxicam (internal standard), respectively. The chromatographic separation was obtained within 2.0 min, and calibration curves were linear in the concentration range of 1-5000 ng/mL. Validation parameters, such as specificity, linearity, precision, accuracy, and robustness, were evaluated, which gave results within the acceptable range for both methods. Moreover, the proposed methods were successfully applied for routine quality control analysis of pharmaceutical products and showed significant correlation (r = 0.9999) of the results.
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MESH Headings
- Chemistry, Pharmaceutical
- Chromatography, Liquid/methods
- Chromatography, Liquid/standards
- Chromatography, Liquid/statistics & numerical data
- Cyclooxygenase Inhibitors/analysis
- Etoricoxib
- Mass Spectrometry/methods
- Mass Spectrometry/standards
- Mass Spectrometry/statistics & numerical data
- Pyridines/analysis
- Quality Control
- Sensitivity and Specificity
- Spectrometry, Mass, Electrospray Ionization/methods
- Spectrometry, Mass, Electrospray Ionization/standards
- Spectrometry, Mass, Electrospray Ionization/statistics & numerical data
- Sulfones/analysis
- Tablets
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Affiliation(s)
- Liberato Brum
- Federal University of Santa Maria, Health Science Center, Postgraduate Program in Pharmaceutical Sciences, Santa Maria, Brazil
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36
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Lim KB, Kassel DB. Phosphopeptides enrichment using on-line two-dimensional strong cation exchange followed by reversed-phase liquid chromatography/mass spectrometry. Anal Biochem 2006; 354:213-9. [PMID: 16750159 DOI: 10.1016/j.ab.2006.04.027] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2006] [Revised: 04/12/2006] [Accepted: 04/18/2006] [Indexed: 11/28/2022]
Abstract
We have developed a method to isolate and enhance the detection of phosphopeptides using liquid chromatography (LC)/mass spectrometry on a tryptic-digested protein sample. The method uses an on-line two-dimensional chromatography approach that consists of strong cation exchange (SCX) followed by reversed-phase (RP) chromatography with mass spectrometric detection. At pH 2.6 or lower, tryptic phosphopeptides are not retained during the first-dimension SCX chromatography step. Thus the capture of these peptides in the flow-through by the second-dimension RP trap can dramatically reduce the complexity of the phosphopeptide chromatography, resulting in little or no suppression of the signal often caused by the coeluting nonphosphorylated peptides. The method provides higher phosphopeptide recovery and less nonspecific biding of acidic peptides than the commonly used enrichment methods, such as immobilized metal affinity chromatography. Since the widely adopted multidimensional LC strategy in shotgun proteomics uses a similar SCX-RP approach, the method can be adapted to detect and characterize phosphopeptides from a complex mixture in a single experiment. Limitations of the method are also discussed.
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Affiliation(s)
- Kheng B Lim
- Takeda San Diego, Inc., San Diego, CA 92121, USA.
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37
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Abstract
It is now apparent that each of the known, naturally occurring polyphosphoinositides, the phosphatidylinositol monophosphates (PtdIns3P, PtdIns4P, PtdIns5P), phosphatidylinositol bisphosphates [PtdIns(3,4)P(2), PtdIns(3,5)P(2), PtdIns(4,5)P(2)], and phosphatidylinositol trisphosphate [PtdIns(3,4,5)P(3)], have distinct roles in regulating many cellular events, including intracellular signaling, migration, and vesicular trafficking. Traditional identification techniques require [(32)P]inorganic phosphate or [(3)H]inositol radiolabeling, acidified lipid extraction, deacylation, and ion-exchange head group separation, which are time-consuming and not suitable for samples in which radiolabeling is impractical, thus greatly restricting the study of these lipids in many physiologically relevant systems. Thus, we have developed a novel, high-efficiency, buffered citrate extraction methodology to minimize acid-induced phosphoinositide degradation, together with a high-sensitivity liquid chromatography-mass spectrometry (LC-MS) protocol using an acetonitrile-chloroform-methanol-water-ethylamine gradient with a microbore silica column that enables the identification and quantification of all phosphoinositides in a sample. The liquid chromatograph is sufficient to resolve PtdInsP(3) and PtdInsP(2) regioisomers; however, the PtdInsP regioisomers require a combination of LC and diagnostic fragmentation to MS(3). Data are presented using this approach for the analysis of phosphoinositides in human platelet and yeast samples.
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Affiliation(s)
- Trevor R Pettitt
- Cancer Research UK Institute for Cancer Studies, University of Birmingham, Birmingham B15 2TH, UK
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38
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Marini RD, Chiap P, Boulanger B, Rudaz S, Rozet E, Crommen J, Hubert P. [Comparison of three approaches for uncertainty estimation]. Acta Clin Belg 2006; 61 Suppl 1:60-2. [PMID: 16700155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Three different approaches for the estimation of uncertainty measurements using the same analytical method were compared, namely validation, robustness and inter-laboratory studies. The uncertainty obtained with the robustness study! predicted well the uncertainty of the inter-laboratory study. On the other hand, the uncertainty estimation obtained with the validation study is lower than those obtained with the two other approaches but is still acceptable as long as the analytical method will be used in a single laboratory.
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Affiliation(s)
- R D Marini
- Laboratoire de Chimie Analytique, Institut de Pharmacie, Université de Liège, CHU, B36, B-4000 Liège, Belgique
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39
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Maurer HH. Multi-analyte procedures for screening for and quantification of drugs in blood, plasma, or serum by liquid chromatography-single stage or tandem mass spectrometry (LC-MS or LC-MS/MS) relevant to clinical and forensic toxicology. Clin Biochem 2005; 38:310-8. [PMID: 15766732 DOI: 10.1016/j.clinbiochem.2005.01.014] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2004] [Accepted: 01/17/2005] [Indexed: 11/17/2022]
Abstract
This paper reviews multi-analyte procedures for screening and quantification of drugs in blood, plasma, or serum using liquid chromatography coupled with a single stage or tandem mass spectrometer (LC-MS, LC-MS/MS). These procedures are relevant tools in clinical and forensic toxicology, and cover analysis of amphetamines, cocaine, hallucinogens, opioids, anesthetics, hypnotics, benzodiazepines, antidepressants, neuroleptics, antihistamines, sulfonylurea-type antidiabetics, beta-blockers, and other cardiac drugs. Basic information on the procedures is given in two tables and multi-analyte screening, identification, and quantification are illustrated in three figures. A critical discussion on the pros and cons of such LC-MS procedures is also included.
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Affiliation(s)
- Hans H Maurer
- Department of Experimental and Clinical Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, University of Saarland, D-66421 Homburg (Saar), Germany.
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40
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Li XJ, Zhang H, Ranish JA, Aebersold R. Automated statistical analysis of protein abundance ratios from data generated by stable-isotope dilution and tandem mass spectrometry. Anal Chem 2003; 75:6648-57. [PMID: 14640741 DOI: 10.1021/ac034633i] [Citation(s) in RCA: 286] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe an algorithm for the automated statistical analysis of protein abundance ratios (ASAPRatio) of proteins contained in two samples. Proteins are labeled with distinct stable-isotope tags and fragmented, and the tagged peptide fragments are separated by liquid chromatography (LC) and analyzed by electrospray ionization (ESI) tandem mass spectrometry (MS/MS). The algorithm utilizes the signals recorded for the different isotopic forms of peptides of identical sequence and numerical and statistical methods, such as Savitzky-Golay smoothing filters, statistics for weighted samples, and Dixon's test for outliers, to evaluate protein abundance ratios and their associated errors. The algorithm also provides a statistical assessment to distinguish proteins of significant abundance changes from a population of proteins of unchanged abundance. To evaluate its performance, two sets of LC-ESI-MS/MS data were analyzed by the ASAPRatio algorithm without human intervention, and the data were related to the expected and manually validated values. The utility of the ASAPRatio program was clearly demonstrated by its speed and the accuracy of the generated protein abundance ratios and by its capability to identify specific core components of the RNA polymerase II transcription complex within a high background of copurifying proteins.
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Affiliation(s)
- Xiao-Jun Li
- The Institute for Systems Biology, 1441 North 34th Street, Seattle, Washington 98103-8904, USA
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41
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Staatz CE, Taylor PJ, Tett SE. Comparison of an ELISA and an LC/MS/MS method for measuring tacrolimus concentrations and making dosage decisions in transplant recipients. Ther Drug Monit 2002; 24:607-15. [PMID: 12352932 DOI: 10.1097/00007691-200210000-00005] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
This study compared an enzyme-linked immunosorbent assay (ELISA) to a liquid chromatography-tandem mass spectrometry (LC/MS/MS) technique for measurement of tacrolimus concentrations in adult kidney and liver transplant recipients, and investigated how assay choice influenced pharmacokinetic parameter estimates and drug dosage decisions. Tacrolimus concentrations measured by both ELISA and LC/MS/MS from 29 kidney (n = 98 samples) and 27 liver (n = 97 samples) transplant recipients were used to evaluate the performance of these methods in the clinical setting. Tacrolimus concentrations measured by the two techniques were compared via regression analysis. Population pharmacokinetic models were developed independently using ELISA and LC/MS/MS data from 76 kidney recipients. Derived kinetic parameters were used to formulate "typical dosing" regimens for concentration targeting. Dosage recommendations for the two assays were compared. The relation between LC/MS/MS and ELISA measurements was best described by the regression equation ELISA = 1.02. (LC/MS/MS) + 0.14 in kidney recipients, and ELISA = 1.12. (LC/MS/MS) - 0.87 in liver recipients. ELISA displayed less accuracy than LC/MS/MS at lower tacrolimus concentrations. Population pharmacokinetic models based on ELISA and LC/MS/MS data were similar with residual random errors of 4.1 ng/mL and 3.7 ng/mL, respectively. Assay choice gave rise to dosage prediction differences ranging from 0% to 30%. ELISA measurements of tacrolimus are not automatically interchangeable with LC/MS/MS values. Assay differences were greatest in adult liver recipients, probably reflecting periods of liver dysfunction and impaired biliary secretion of metabolites. While the majority of data collected in this study suggested assay differences in adult kidney recipients were minimal, findings of ELISA dosage underpredictions of up to 25% in the long term must be investigated further.
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Affiliation(s)
- Christine E Staatz
- School of Phamacy, University of Queensland, Princess Alexandra Hospital, Queensland, Australia.
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42
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Wall DB, Berger SJ, Finch JW, Cohen SA, Richardson K, Chapman R, Drabble D, Brown J, Gostick D. Continuous sample deposition from reversed-phase liquid chromatography to tracks on a matrix-assisted laser desorption/ionization precoated target for the analysis of protein digests. Electrophoresis 2002; 23:3193-204. [PMID: 12298091 DOI: 10.1002/1522-2683(200209)23:18<3193::aid-elps3193>3.0.co;2-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Peptide mass fingerprinting by matrix-assisted laser desorption/ionization (MALDI)-mass spectrometry (MS) is one of the standard high-throughput methods for protein identification today. Traditionally this method has been based on spotting peptide mixtures onto MALDI targets. While this method works well for more abundant proteins, low-abundance proteins mixed with high-abundance proteins tend to go undetected due to ion suppression effects, instrumental dynamic range limitations and chemical noise interference. We present an alternative approach where liquid chromatography (LC) effluent is continuously collected as linear tracks on a MALDI target. In this manner the chromatographic separation is spatially preserved on the target, which enables generation of off-line LC-MS and LC-MS/MS data by MALDI. LC-MALDI sample collection provides improved sensitivity and dynamic range, spatial resolution of peptides along the sample track, and permits peptide mass mapping of low-abundance proteins in mixtures containing high-abundance proteins. In this work, standard and ribosomal protein digests are resolved and captured using LC-MALDI sample collection and analyzed by MALDI-TOF-MS.
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Tai SSC, Sniegoski LT, Welch MJ. Candidate reference method for total thyroxine in human serum: use of isotope-dilution liquid chromatography-mass spectrometry with electrospray ionization. Clin Chem 2002; 48:637-42. [PMID: 11901062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
BACKGROUND There is a need for a critically evaluated reference method for thyroxine to provide an accuracy base to which routine methods can be traceable. We describe a candidate reference method involving isotope-dilution coupled with liquid chromatography/mass spectrometry. METHODS An isotopically labeled internal standard, thyroxine-d(5), was added to serum, followed by equilibration, protein precipitation, and ethyl acetate and solid-phase extractions to prepare samples for liquid chromatography-mass spectrometry electrospray ionization (LC/MS-ESI) analysis. For separation, a Zorbax Eclipse XDB-C(18) column was used with a mobile phase consisting of 1 mL/L acetic acid in acetonitrile-water (32:68 by volume) for positive ions and a Zorbax Extend-C(18) column with a mobile phase consisting of 2 mL/L ammonium hydroxide in methanol-water (32:68 by volume) for negative ions. [M + H](+) ions at m/z 778 and 783 for thyroxine and its labeled internal standard were monitored for positive ions and [M - H](-) ions at m/z 776 and 781 for negative ions. Samples of frozen serum pools were prepared and measured in three separate sets. RESULTS Within-set CVs were 0.2-1.0%. The correlation coefficients of all linear regression lines (measured intensity ratios vs mass ratios) were 0.999-1.000. Positive- and negative-ion measurements agreed with a mean difference of 0.45% at three concentrations (50, 110, and 168 microg/L). The detection limits (at a signal-to-noise ratio of approximately 3 to 5) were 30 and 20 pg for positive and negative ions, respectively. The results from the LC/MS-ESI method were within 1 SD of the composite means from many routine clinical methods, although it appears that the clinical method means may be biased high by 4-5 microg/L across the concentrations. Some routine clinical methods may be biased by up to 20% at low concentrations. CONCLUSIONS This well-characterized LC/MS-ESI method for total serum thyroxine with a theoretically sound approach, demonstrated good accuracy and precision, and low susceptibility to interferences qualifies as a candidate reference method. Use of this reference method as an accuracy base may reduce the apparent biases in routine methods along with the high interlaboratory imprecision.
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Affiliation(s)
- Susan S-C Tai
- Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, MD 20899-8392, USA.
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44
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Kim JS, Nafziger AN, Tsunoda SM, Choo EE, Streetman DS, Kashuba ADM, Kulawy RW, Beck DJ, Rocci ML, Wilkinson GR, Greenblatt DJ, Bertino JS. Limited sampling strategy to predict AUC of the CYP3A phenotyping probe midazolam in adults: application to various assay techniques. J Clin Pharmacol 2002; 42:376-82. [PMID: 11936561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Midazolam clearance is used to phenotype hepatic CYP3A activity but requires multiple plasma samples following a single intravenous dose. The authors evaluated the use of a limited sampling scheme, using different assay techniques to determine the reproducibility of such a strategy in estimating midazolam AUC. Seventy-three healthy adults received midazolam as a single intravenous bolus dose. At least eight plasma samples were collected from each subject and were assayed using either LC/MS/MS or electron capture gas chromatography. Eleven subjects were randomly selected for the training set using stepwise linear regression to determine relationships between midazolam plasma concentrations and AUC. Validation of the predictive equations was done using the remaining 62 subjects. Mean percent error (MPE), mean absolute error (MAE), and root mean square error (RMSE) were calculated to determine bias and precision. Based on the training set, five models were generated with coefficients of determination ranging from 0.87 to 0.95. Validation showed that MPE, MAE, and RMSE values were acceptable for three of the models. Intrasubject reproducibility was good. In addition, training set datafrom one institution were able to predict data from the other two institutions using other assay techniques. Minimized plasma sampling mayprovide a simpler method for estimating midazolam AUC for CYP3A phenotyping. A limited sampling strategy is more convenient and cost-effective than standard sampling strategies and is applicable to more than one assay technique.
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Affiliation(s)
- Jooran S Kim
- Clinical Pharmacology Research Center, Bassett Healthcare, Cooperstown, New York 13326-1394, USA
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45
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Hastings CA, Norton SM, Roy S. New algorithms for processing and peak detection in liquid chromatography/mass spectrometry data. Rapid Commun Mass Spectrom 2002; 16:462-467. [PMID: 11857732 DOI: 10.1002/rcm.600] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Two new algorithms for automated processing of liquid chromatography/mass spectrometry (LC/MS) data are presented. These algorithms were developed from an analysis of the noise and artifact distribution in such data. The noise distribution was analyzed by preparing histograms of the signal intensity in LC/MS data. These histograms are well fit by a sum of two normal distributions in the log scale. One new algorithm, median filtering, provides increased performance compared to averaging adjacent scans in removing noise that is not normally distributed in the linear scale. Another new algorithm, vectorized peak detection, provides increased robustness with respect to variation in the noise and artifact distribution compared to methods based on determining an intensity threshold for the entire dataset. Vectorized peak detection also permits the incorporation of existing algorithms for peak detection in ion chromatograms and/or mass spectra. The application of these methods to LC/MS spectra of complex biological samples is described.
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Dagenais C, Ducharme J, Pollack GM. Interaction of nonpeptidic delta agonists with P-glycoprotein by in situ mouse brain perfusion: liquid chromatography-mass spectrometry analysis and internal standard strategy. J Pharm Sci 2002; 91:244-52. [PMID: 11782913 DOI: 10.1002/jps.1175] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many opioids are substrates of the efflux transporter P-glycoprotein (P-gp) in the blood-brain barrier (BBB). In situ brain perfusion in wild-type and mdr 1a(-/-) P-gp-deficient mice was utilized to investigate potential P-gp-mediated transport of novel nonpeptidic delta agonists (AR-M delta compounds). Because radioactive compounds were not available for this series, liquid chromatography-mass spectrometric detection (LC-MS) was the assay methodology of choice. Verapamil in the perfusion buffer (0.5 microM) served as a positive control for P-gp-mediated efflux and as an experimental internal standard for P-gp modulation by AR-M delta compounds. LC-MS provided excellent assay sensitivity with no significant interferences. In P-gp-competent mice, the brain extraction of AR-M delta compounds ranged from 1.1 to 96%. The ratio of initial brain uptake clearances (Cl(up)) in P-gp-deficient and wild-type mice (P-gp effect) ranged from 0.96 to 4.91. Some compounds increased the Cl(up) of verapamil in P-gp-competent mice, consistent with P-gp inhibition. These results demonstrate that LC-MS is an appropriate assay methodology for mouse brain perfusion samples, that AR-M delta compounds may interact with P-gp in the BBB, and that the internal strategy can provide useful information concerning P-gp modulation by compounds of interest.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B/deficiency
- ATP Binding Cassette Transporter, Subfamily B/metabolism
- ATP Binding Cassette Transporter, Subfamily B, Member 1/deficiency
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- ATP-Binding Cassette Transporters/metabolism
- Animals
- Brain/blood supply
- Brain/metabolism
- Calcium Channel Blockers/pharmacokinetics
- Chromatography, Liquid/methods
- Chromatography, Liquid/statistics & numerical data
- Male
- Mass Spectrometry/methods
- Mass Spectrometry/statistics & numerical data
- Mice
- Mice, Knockout
- Perfusion/methods
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/metabolism
- Verapamil/pharmacokinetics
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Affiliation(s)
- Claude Dagenais
- Division of Drug Delivery and Disposition, School of Pharmacy, University of North Carolina at Chapel Hill, 27599-7360, USA
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Visconti A, Solfrizzo M, De Girolamo A. Determination of fumonisins B1 and B2 in corn and corn flakes by liquid chromatography with immunoaffinity column cleanup: collaborative study. J AOAC Int 2001; 84:1828-37. [PMID: 11767152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
A liquid chromatographic (LC) method for the determination of fumonisins B1 (FB1) and B2 (FB2) in corn and corn flakes was collaboratively studied by 23 laboratories, which analyzed 5 blind duplicate pairs of each matrix to establish the accuracy, repeatability, and reproducibility characteristics of the method. Fumonisin levels in the corn ranged from <0.05 (blank) to 1.41 microg/g for FB1 and from <0.05 to 0.56 microg/g for FB2, whereas in the corn flakes they ranged from <0.05 to 1.05 microg/g for FB1 and from <0.05 to 0.46 microg/g for FB2. The method involved double extraction with acetonitrile-methanol-water (25 + 25 + 50), cleanup through an immunoaffinity column, and LC determination of the fumonisins after derivatization with o-phthaldialdehyde. Relative standard deviations for the within-laboratory repeatability (RSDr) of the corn analyses ranged from 19 to 24% for FB1 and from 19 to 27% for FB2; for the corn flakes analyses, RSDr ranged from 9 to 21 % for FB1 and from 8 to 22% for FB2. Relative standard deviations for the between-laboratories reproducibility (RSDR) of the corn analyses ranged from 22 to 28% for FB1 and from 22 to 30% for the FB2; for corn flakes analyses, RSDR ranged from 27 to 32% for FB1 and from 26 to 35% for FB2. Mean recoveries of FB1 and FB2 from corn spiked with FB1 at 0.80 microg/g and with FB2 at 0.40 microg/g were 76 and 72%, respectively; for corn flakes spiked at the same levels recoveries were 110 and 97% for FB1 and FB2, respectively. HORRAT ratios for the analyses of corn ranged from 1.44 to 1.53 for FB1 and from 0.96 to 1.48 for FB2, whereas for corn flakes they ranged from 1.60 to 1.82 for FB1 and from 1.39 to 1.68 for FB2.
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Affiliation(s)
- A Visconti
- Istituto Tossine e Micotossine da Parassiti Vegetali, Consiglio Nazionale delle Ricerche (CNR), Bari, Italy.
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Klump SP, Allred MC, MacDonald JL, Ballam JM. Determination of isoflavones in soy and selected foods containing soy by extraction, saponification, and liquid chromatography: collaborative study. J AOAC Int 2001; 84:1865-83. [PMID: 11767157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Isoflavones are biologically active compounds occurring naturally in a variety of plants, with relatively high levels found in soybeans. Twelve laboratories participated in a collaborative study to determine the aglycon isoflavone content of 8 test samples of soy and foods containing soy. The analytical method for the determination of isoflavones incorporates a mild saponification step that reduces the number of analytes measured and permits quantitation versus commercially available, stable reference standards. Test samples were extracted at 65 degrees C with methanol-water (80 + 20), saponified with dilute sodium hydroxide solution, and analyzed by reversed-phase liquid chromatography with UV detection at 260 nm. Isoflavone results were reported as microg/aglycon/g or microg aglycon equivalents/g. The 8 test samples included 2 blind duplicates and 4 single test samples with total isoflavone concentrations ranging from approximately 50 to 3000 microg/g. Test samples of soy ingredients and products made with soy were distributed to collaborators with appropriate reference standards. Collaborators were asked to analyze test samples in duplicate on 2 separate days. The data were analyzed for individual isoflavone components, subtotals of daidzin-daidzein, glycitin-glycitein, and genistin-genistein, and total isoflavones. The relative standard deviation (RSD) for repeatability was 1.8-7.1%, and the RSD for reproducibility was 3.2-16.1% for total isoflavone values of 47-3099 microg/g.
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Affiliation(s)
- S P Klump
- Ralston Analytical Laboratories, Saint Louis, MO 63164, USA
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Visconti A, Pascale M, Centonze G. Determination of ochratoxin A in wine and beer by immunoaffinity column cleanup and liquid chromatographic analysis with fluorometric detection: collaborative study. J AOAC Int 2001; 84:1818-27. [PMID: 11767151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
The accuracy, repeatability, and reproducibility characteristics of a liquid chromatographic method for the determination of ochratoxin A (OTA) in white wine, red wine, and beer were established in a collaborative study involving 18 laboratories in 10 countries. Blind duplicates of blank, spiked, and naturally contaminated materials at levels ranging from < or =0.01 to 3.00 ng/mL were analyzed. Wine and beer samples were diluted with a solution containing polyethylene glycol and sodium hydrogen carbonate, and the diluted samples were filtered and cleaned up on an immunoaffinity column. OTA was eluted with methanol and quantified by reversed-phase liquid chromatography with fluorometric detection. Average recoveries from white wine, red wine, and beer ranged from 88.2 to 105.4% (at spiking levels ranging from 0.1 to 2.0 ng/mL), from 84.3 to 93.1% (at spiking levels ranging from 0.2 to 3.0 ng/mL), and from 87.0 to 95.0% (at spiking levels ranging from 0.2 to 1.5 ng/mL), respectively. Relative standard deviations for within-laboratory repeatability (RSDr) ranged from 6.6 to 10.8% for white wine, from 6.5 to 10.8% for red wine, and from 4.7 to 16.5% for beer. Relative standard deviations for between-laboratories reproducibility (RSDR) ranged from 13.1 to 15.9% for white wine, from 11.9 to 13.6% for red wine, and from 15.2 to 26.1% for beer. HORRAT values were < or =0.4 for the 3 matrixes.
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Affiliation(s)
- A Visconti
- Istituto Tossine e Micotossine da Parassiti Vegetali, Consiglio Nazionale delle Ricerche (CNR), Bari, Italy.
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Vogeser M, Briegel J, Jacob K. Determination of serum cortisol by isotope-dilution liquid-chromatography electrospray ionization tandem mass spectrometry with on-line extraction. Clin Chem Lab Med 2001; 39:944-7. [PMID: 11758607 DOI: 10.1515/cclm.2001.151] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A liquid chromatographic-mass spectrometric method for the determination of cortisol in serum using atmospheric pressure electrospray ionization and tandem mass spectrometry is described. During sample preparation, 150 microl of serum were deproteinized with methanol/zinc sulfate followed by on-line solid phase extraction employing column switching. Tri-deuterated cortisol was used as the internal standard. The following transitions were monitored: cortisol, 363>309 m/z; d3-cortisol, 366>312 m/z. The total run-time was 5 minutes. The method proved linear (0-500 microg/l; r=0.999), precise (total coefficient of variation between 5.0% and 3.2% at a mean cortisol concentration of 15.1 microg/l and 269 microg/l, respectively; n=16) and specific with regard to relevant endogenous and exogenous steroids.
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Affiliation(s)
- M Vogeser
- Institute of Clinical Chemistry, Ludwig-Maximilians-Universität München, Klinikum Grosshadern, Munich, Germany.
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