1
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Jeong YH, Eun D, Van Kien N, Seog DJH, Ryoo JJ. Use of ultrasound in gradient elution of
Polycyclic Aromatic Hydrocarbon
mixtures by
HPLC. B KOREAN CHEM SOC 2023. [DOI: 10.1002/bkcs.12700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Affiliation(s)
- Young Han Jeong
- Department of Chemistry Kyungpook National University Daegu 41566 South Korea
| | - Danbi Eun
- Department of Chemistry Education Kyungpook National University Daegu 41566 South Korea
| | - Nguyen Van Kien
- Department of Chemistry Education Kyungpook National University Daegu 41566 South Korea
| | - David Jin Han Seog
- Department of Chemistry Education Kyungpook National University Daegu 41566 South Korea
| | - Jae Jeong Ryoo
- Department of Chemistry Education Kyungpook National University Daegu 41566 South Korea
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2
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Isolation and Purification of a Hydrophobic Non-Ribosomal Peptide from an Escherichia coli Fermentation Broth. SEPARATIONS 2021. [DOI: 10.3390/separations8120241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Non-ribosomal peptide synthases (NRPSs) generate versatile bioactive peptides by incorporating non-proteinogenic amino acids and catalyzing diverse modifications. Here, we developed an efficient downstream process for the capture, intermediate purification and polishing of a rhabdopeptide (RXP) produced by the NRPS VietABC. Many typical unit operations were unsuitable due to the similar physical and chemical properties of the RXP and related byproducts. However, we were able to capture the RXP from a fermentation broth using a hydrophobic resin (XAD-16N), resulting in a 14-fold increase in concentration while removing salts as well as polar and weak non-polar impurities. We then used ultra-high-performance liquid chromatography (UHPLC) for intermediate purification, with optimized parameters determined using statistical experimental designs, resulting in the complete removal of hydrophobic impurities. Finally, the UHPLC eluents were removed by evaporation. Our three-step downstream process achieved an overall product recovery of 81.7 ± 8.4%.
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3
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Reversed-phase pH gradient thin-layer chromatography of biologically active substances with controlled developing solvent velocity. J Chromatogr A 2021; 1649:462224. [PMID: 34038787 DOI: 10.1016/j.chroma.2021.462224] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/22/2021] [Accepted: 04/28/2021] [Indexed: 11/23/2022]
Abstract
For the first time, stepwise pH gradient thin-layer chromatograms of biologically active substances with controlled developing solvent velocity are presented and described in the paper. Change in buffer pH of the mobile phase solution influences retardation, selectivity, and shape of the separated substances' spots. The conducted research has confirmed that the mobile phase's pH gradient could be an essential factor to optimize the conditions of the separation of substances in reversed-phase high-performance thin-layer chromatography. The reproducibility of the gradient retardation factor values of separated substance zones is satisfactory.
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4
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Biancolillo A, Maggi MA, Bassi S, Marini F, D’Archivio AA. Retention Modelling of Phenoxy Acid Herbicides in Reversed-Phase HPLC under Gradient Elution. Molecules 2020; 25:molecules25061262. [PMID: 32168813 PMCID: PMC7144001 DOI: 10.3390/molecules25061262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 03/01/2020] [Accepted: 03/11/2020] [Indexed: 12/02/2022] Open
Abstract
Phenoxy acid herbicides are used worldwide and are potential contaminants of drinking water. Reversed phase high-performance liquid chromatography (RP-HPLC) is commonly used to monitor phenoxy acid herbicides in water samples. RP-HPLC retention of phenoxy acids is affected by both mobile phase composition and pH, but the synergic effect of these two factors, which is also dependent on the structure and pKa of solutes, cannot be easily predicted. In this paper, to support the setup of RP-HPLC analysis of phenoxy acids under application of linear mobile phase gradients we modelled the simultaneous effect of the molecular structure and the elution conditions (pH, initial acetonitrile content in the eluent and gradient slope) on the retention of the solutes. In particular, the chromatographic conditions and the molecular descriptors collected on the analyzed compounds were used to estimate the retention factor k by Partial Least Squares (PLS) regression. Eventually, a variable selection approach, Genetic Algorithms, was used to reduce the model complexity and allow an easier interpretation. The PLS model calibrated on the retention data of 15 solutes and successively tested on three external analytes provided satisfying and reliable results.
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Affiliation(s)
- Alessandra Biancolillo
- Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell’Aquila, Via Vetoio, Coppito, 67100 L’Aquila (AQ), Italy;
| | - Maria Anna Maggi
- Hortus Novus srl, Via Campo Sportivo 2, Canistro, 67100 L’Aquila, Italy;
| | - Sebastian Bassi
- Dipartimento di Chimica, Università degli Studi di Roma “La Sapienza”, Piazzale Aldo Moro 5, 00185 Roma, Italy; (S.B.); (F.M.)
| | - Federico Marini
- Dipartimento di Chimica, Università degli Studi di Roma “La Sapienza”, Piazzale Aldo Moro 5, 00185 Roma, Italy; (S.B.); (F.M.)
| | - Angelo Antonio D’Archivio
- Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell’Aquila, Via Vetoio, Coppito, 67100 L’Aquila (AQ), Italy;
- Correspondence:
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5
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Tóth G, Vékey K, Drahos L, Horváth V, Turiák L. Salt and solvent effects in the microscale chromatographic separation of heparan sulfate disaccharides. J Chromatogr A 2019; 1610:460548. [PMID: 31547957 DOI: 10.1016/j.chroma.2019.460548] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 08/28/2019] [Accepted: 09/14/2019] [Indexed: 12/25/2022]
Abstract
The analysis of heparan sulfate disaccharides poses a real challenge both from chromatographic and mass spectrometric point of view. This necessitates the constant improvement of their analytical methodology. In the present study, the chromatographic effects of solvent composition, salt concentration, and salt type were systematically investigated in isocratic HILIC-WAX separations of heparan sulfate disaccharides. The combined use of 75% acetonitrile with ammonium formate had overall benefits regarding intensity, detection limits, and peak shape for all salt concentrations investigated. Results obtained with the isocratic measurements suggested the potential use of a salt gradient method in order to maximize separation efficiency. A 3-step gradient from 14 mM to 65 mM ammonium formate concentration proved to be ideal for separation and quantitation. The LOD of the resulting method was 0.8-1.5 fmol for the individual disaccharides and the LOQ was between 2.5-5 fmol. Outstanding linearity could be observed up to 2 pmol. This novel combination provided sufficient sensitivity for disaccharide analysis, which was demonstrated by the analysis of heparan sulfate samples from porcine and bovine origin.
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Affiliation(s)
- Gábor Tóth
- MS Proteomics Research Group, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2., H-1117 Budapest, Hungary; Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szent Gellért tér 4., H-1111 Budapest, Hungary
| | - Károly Vékey
- MS Proteomics Research Group, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2., H-1117 Budapest, Hungary
| | - László Drahos
- MS Proteomics Research Group, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2., H-1117 Budapest, Hungary
| | - Viola Horváth
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szent Gellért tér 4., H-1111 Budapest, Hungary; MTA-BME Computation Driven Chemistry Research Group, Szent Gellért tér 4., H-1111 Budapest, Hungary
| | - Lilla Turiák
- MS Proteomics Research Group, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2., H-1117 Budapest, Hungary.
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6
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Artificial Neural Network Prediction of Retention of Amino Acids in Reversed-Phase HPLC under Application of Linear Organic Modifier Gradients and/or pH Gradients. Molecules 2019; 24:molecules24030632. [PMID: 30754702 PMCID: PMC6384946 DOI: 10.3390/molecules24030632] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 02/06/2019] [Accepted: 02/07/2019] [Indexed: 12/29/2022] Open
Abstract
A multi-layer artificial neural network (ANN) was used to model the retention behavior of 16 o-phthalaldehyde derivatives of amino acids in reversed-phase liquid chromatography under application of various gradient elution modes. The retention data, taken from literature, were collected in acetonitrile⁻water eluents under application of linear organic modifier gradients ( gradients), pH gradients, or double pH/ gradients. At first, retention data collected in gradients and pH gradients were modeled separately, while these were successively combined in one dataset and fitted simultaneously. Specific ANN-based models were generated by combining the descriptors of the gradient profiles with 16 inputs representing the amino acids and providing the retention time of these solutes as the response. Categorical "bit-string" descriptors were adopted to identify the solutes, which allowed simultaneously modeling the retention times of all 16 target amino acids. The ANN-based models tested on external gradients provided mean errors for the predicted retention times of 1.1% ( gradients), 1.4% (pH gradients), 2.5% (combined and pH gradients), and 2.5% (double pH/ gradients). The accuracy of ANN prediction was better than that previously obtained by fitting of the same data with retention models based on the solution of the fundamental equation of gradient elution.
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7
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Shi F, Liu J. Simultaneous determination of the lipophilicity and dissociation constants of dialkyl phosphinic acids by negligible depletion hollow fiber membrane-protected liquid-phase microextraction. J Chromatogr A 2017; 1507:11-17. [PMID: 28599859 DOI: 10.1016/j.chroma.2017.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 05/31/2017] [Accepted: 06/01/2017] [Indexed: 11/17/2022]
Abstract
Determination of the physicochemical properties, especially the lipophilicity (expressed as the logarithm of distribution coefficient, log D) and dissociation constant (pKa), is of great importance in the early stage of environmental risk assessment for an ionizable compound without these data. Currently, the log D and pKa values of dialkyl phosphinic acids (DPAs), the environmental hydrolysates of aluminum dialkyl phosphinates (ADPs) that is one class of emerging phosphorus-containing flame retardants, are not available. In this study, the log D and pKa values of three DPAs including methylethylphosphinic acid (MEPA), diethylphosphinic acid (DEPA) and methylcyclohexyl phosphinic acid (MHPA), were simultaneously determined by negligible depletion hollow fiber supported liquid phase microextraction (nd-HF-LPME) followed by ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The pKa and log D of DPAs were determined by curve-fitting the experimental data with equations derived on the basis of the Henderson-Hasselbalch equation and compared with model calculated data. For MEPA, DEPA and MHPA, the pKa values were close and around 3, but the log Ds were strongly pH-dependent with values from -5.01 to 1.01. The log KOW of the neutral form (logKOW,HA) and ionic form (logKOW,A) were in the range of -0.67-1.02 and -3.86--1.33, respectively. The experimentally determined pKa values were highly in good agreement with ACD/pKa predicted values and the measured log KOW,HA values were closely related to KOWWIN calculated ones, suggesting ACD/pKa and KOWWIN are good alternative methods to estimate pKa and log KOW of DPAs, respectively. As far as we know, this is the first report on the pKa and log D data for DPAs, which are fundamental for the product design and evaluating the environmental behavior and effects of DPAs and ADPs.
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Affiliation(s)
- Fengqiong Shi
- State Key Laboratory of Environmental and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jingfu Liu
- State Key Laboratory of Environmental and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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8
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Multiple, simultaneous, independent gradients for a versatile multidimensional liquid chromatography. Part II: Application 1 - Large increases in isoform resolution of human transferrin by use of dual simultaneous independent gradients of pH & acetonitrile on a mixed bed (anion exchange plus reversed phase) stationary phase. J Chromatogr A 2016; 1468:173-182. [DOI: 10.1016/j.chroma.2016.09.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 09/20/2016] [Accepted: 09/21/2016] [Indexed: 11/19/2022]
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9
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Fasoula S, Zisi C, Gika H, Pappa-Louisi A, Nikitas P. Retention prediction and separation optimization under multilinear gradient elution in liquid chromatography with Microsoft Excel macros. J Chromatogr A 2015; 1395:109-15. [DOI: 10.1016/j.chroma.2015.03.068] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/20/2015] [Accepted: 03/23/2015] [Indexed: 10/23/2022]
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10
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Wiczling P, Struck-Lewicka W, Kubik Ł, Siluk D, Markuszewski M, Kaliszan R. The simultaneous determination of hydrophobicity and dissociation constant by liquid chromatography–mass spectrometry. J Pharm Biomed Anal 2014; 94:180-7. [DOI: 10.1016/j.jpba.2014.01.038] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 01/23/2014] [Indexed: 11/16/2022]
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11
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Trifluoroacetic Acid in 2,2,2-Trifluoroethanol Facilitates SNAr Reactions of Heterocycles with Arylamines. Chemistry 2014; 20:2311-7. [DOI: 10.1002/chem.201304336] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Indexed: 11/07/2022]
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12
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Socia A, Foley JP. Sequential elution liquid chromatography can significantly increase the probability of a successful separation by simultaneously increasing the peak capacity and reducing the separation disorder. J Chromatogr A 2014; 1324:36-48. [DOI: 10.1016/j.chroma.2013.11.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 10/29/2013] [Accepted: 11/12/2013] [Indexed: 10/26/2022]
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13
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Zisi C, Fasoula S, Pappa-Louisi A, Nikitas P. Expressions for Multilinear Combined pH/Organic Solvent Elution of Ionizable Analytes in Reversed-Phase HPLC. Anal Chem 2013; 85:9514-21. [DOI: 10.1021/ac4021243] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ch. Zisi
- Laboratory
of Physical Chemistry,
Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - S. Fasoula
- Laboratory
of Physical Chemistry,
Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - A. Pappa-Louisi
- Laboratory
of Physical Chemistry,
Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - P. Nikitas
- Laboratory
of Physical Chemistry,
Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
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14
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Fasoula S, Zisi C, Nikitas P, Pappa-Louisi A. Retention prediction and separation optimization of ionizable analytes in reversed-phase liquid chromatography by organic modifier gradients in different eluent pHs. J Chromatogr A 2013; 1305:131-8. [DOI: 10.1016/j.chroma.2013.07.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 07/02/2013] [Accepted: 07/03/2013] [Indexed: 11/15/2022]
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15
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Ding C, Jiang J, Wei J, Liu W, Zhang W, Liu M, Fu T, Lu T, Song L, Ying W, Chang C, Zhang Y, Ma J, Wei L, Malovannaya A, Jia L, Zhen B, Wang Y, He F, Qian X, Qin J. A fast workflow for identification and quantification of proteomes. Mol Cell Proteomics 2013; 12:2370-80. [PMID: 23669031 DOI: 10.1074/mcp.o112.025023] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The current in-depth proteomics makes use of long chromatography gradient to get access to more peptides for protein identification, resulting in covering of as many as 8000 mammalian gene products in 3 days of mass spectrometer running time. Here we report a fast sequencing (Fast-seq) workflow of the use of dual reverse phase high performance liquid chromatography - mass spectrometry (HPLC-MS) with a short gradient to achieve the same proteome coverage in 0.5 day. We adapted this workflow to a quantitative version (Fast quantification, Fast-quan) that was compatible to large-scale protein quantification. We subjected two identical samples to the Fast-quan workflow, which allowed us to systematically evaluate different parameters that impact the sensitivity and accuracy of the workflow. Using the statistics of significant test, we unraveled the existence of substantial falsely quantified differential proteins and estimated correlation of false quantification rate and parameters that are applied in label-free quantification. We optimized the setting of parameters that may substantially minimize the rate of falsely quantified differential proteins, and further applied them on a real biological process. With improved efficiency and throughput, we expect that the Fast-seq/Fast-quan workflow, allowing pair wise comparison of two proteomes in 1 day may make MS available to the masses and impact biomedical research in a positive way.
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Affiliation(s)
- Chen Ding
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, Beijing 102206, China
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16
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Zisi C, Fasoula S, Nikitas P, Pappa-Louisi A. Retention modeling in combined pH/organic solvent gradient reversed-phase HPLC. Analyst 2013; 138:3771-7. [DOI: 10.1039/c3an36425a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Chester TL. Maximizing the speed of separations for industrial problems. J Chromatogr A 2012; 1261:69-77. [PMID: 22989488 DOI: 10.1016/j.chroma.2012.08.054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 08/15/2012] [Accepted: 08/15/2012] [Indexed: 11/19/2022]
Abstract
Recent improvement efforts in chromatography have provided great improvements in the rate of plate production, but less attention has been spent on optimizing the kinds of problems that are most often encountered in industry. When factors are not independent in their effects on the responses of a chromatographic separation, all adjustable factors must be considered in concert in seeking the best or optimum condition that solves the problem. This requires careful attention to specifying the goals, the adjustable factors, and the constraints required to make sure the outcome can actually be implemented. Strategies for optimizing assay and screening methods in the context of industrial needs are presented. Expanding the factor space of the system being investigated can lead to better outcomes. The prospect of adding column-outlet pressure control and expanding the mobile phase composition to include condensed gases or supercritical fluids is explored. Reversed-phase liquid chromatography, hydrophilic interaction chromatography, electrostatic repulsion hydrophilic interaction chromatography, and supercritical fluid chromatography are contiguous with regard to mobile phase characteristics. Adjustment of selectivity through instrument-controlled factors can benefit method development. Opportunities obtained by blending modifiers, varying temperature and pressure with compressible mobile phases, and controlling pH are discussed in the context of optimizing methods.
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Affiliation(s)
- T L Chester
- Department of Chemistry, University of Cincinnati, P.O. Box 210172, Cincinnati, OH 45221-0172, USA.
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18
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Nikitas P, Pappa-Louisi A, Zisi C. pH-Gradient Reversed-Phase Liquid Chromatography of Ionogenic Analytes Revisited. Anal Chem 2012; 84:6611-8. [DOI: 10.1021/ac300876c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- P. Nikitas
- Laboratory of Physical Chemistry, Department
of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - A. Pappa-Louisi
- Laboratory of Physical Chemistry, Department
of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - Ch. Zisi
- Laboratory of Physical Chemistry, Department
of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
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19
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Hirsh AG, Tsonev LI. Multiple, simultaneous, independent gradients for versatile multidimensional liquid chromatography. Part I: Theory. J Chromatogr A 2012; 1236:51-62. [DOI: 10.1016/j.chroma.2012.02.072] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Revised: 02/21/2012] [Accepted: 02/26/2012] [Indexed: 10/28/2022]
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20
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Pappa-Louisi A, Zisi C. A simple approach for retention prediction in the pH-gradient reversed-phase liquid chromatography. Talanta 2012; 93:279-84. [PMID: 22483911 DOI: 10.1016/j.talanta.2012.02.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 02/10/2012] [Accepted: 02/16/2012] [Indexed: 10/28/2022]
Abstract
A simple approach for retention modeling of solutes under pH-gradient conditions at various organic contents in the mobile phase is proposed. This approach is based on a retention model arising from the evaluation of the retention data of a set of 17 OPA derivatives of amino acids obtained in two series of 22 pH-gradient runs performed between a given initial and final pH value (between 2.8 and 10.7 or 3.2 and 9.0) with different gradient duration and with different organic modifier content in the eluent. The derived model is a fifth-parameter equation easily manageable through a linear least-squares fitting. It requires only 6 initial pH-gradient experiments, allows a very satisfactory prediction for various pH-changes of the same kind with those used in the fitting procedure and seems to be very promising in separation optimization under pH-gradient conditions. The pH-gradient method appears to be especially suitable and effective for separation of amino acid derivatives whereas the application of pH-gradients from 3.2 to 9.0 proved to be beneficial.
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Affiliation(s)
- A Pappa-Louisi
- Laboratory of Physical Chemistry, Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
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21
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Chen Y, Srinivasan K, Dasgupta PK. Electrodialytic Membrane Suppressors for Ion Chromatography Make Programmable Buffer Generators. Anal Chem 2011; 84:67-75. [DOI: 10.1021/ac2023712] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yongjing Chen
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Kannan Srinivasan
- Thermo Fisher Scientific, 445 Lakeside Drive, Sunnyvale, California 94085, United States
| | - Purnendu K. Dasgupta
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019-0065, United States
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22
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Kaliszan R, Wiczling P. Gradient reversed-phase high-performance chromatography of ionogenic analytes. Trends Analyt Chem 2011. [DOI: 10.1016/j.trac.2011.05.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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23
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Ma Y, Zhang W, Wei J, Niu M, Lin H, Qin W, Zhang Y, Qian X. [Reversed-phase liquid chromatography with double gradient elution for the separation and mass spectrometric analysis of peptides]. Se Pu 2011; 29:205-11. [PMID: 21657048 DOI: 10.3724/sp.j.1123.2011.00205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Highly effective separation of complex peptide mixture is a prerequisite for protein identification with high coverage in proteomics. Currently, peptide mixture is separated by two-dimensional liquid chromatography (2D-LC), ion exchange chromatography as the first dimension and reversed-phase chromatography as the second dimension, in Shotgun proteomics. Though the 2D-LC is now widely used, its separation efficiency still needs further improvement. In this work, the first dimensional separation was performed by the pH and organic solvent double-gradient elution. And then the two fractions, one from the early eluted section and the other from the later eluted section (with equal time intervals) were pooled and analyzed by MS/MS. The experimental results from the protein mixture of saccharomyces cerevisiae lysate showed that the separation by pH and organic solvent double-gradient elution, RP-HPLC-nanoRPLC coupled with MS/MS identified 567 more yeast protein groups (3 035 peptides) over strong cation exchange chromatography-nanoRPLC coupled with MS/MS. The pI values and relative molecular masses of identified peptides ranged from 3.42 to 12.01, and from 587.67 to 3 499.79, respectively. The pI values and relative molecular masses of identified proteins ranged from 3.82 to 12.19 and from 3 446.55 to 432 905, respectively. These results indicated that this new 2DLC-MS method has the advantages over the conventional Shotgun method, and were expected to be applied in the separation of complex samples for proteomic studies in the future.
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Affiliation(s)
- Yan Ma
- College of Life Science and Bio-Engineering, Beijing University of Technology, Beijing 100022, China
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24
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Perisic-Janjic N, Kaliszan R, Wiczling P, Milosevic N, Uscumlic G, Banjac N. Reversed-Phase TLC and HPLC Retention Data in Correlation Studies with in Silico Molecular Descriptors and Druglikeness Properties of Newly Synthesized Anticonvulsant Succinimide Derivatives. Mol Pharm 2011; 8:555-63. [DOI: 10.1021/mp100373d] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nada Perisic-Janjic
- Department of Chemistry, Faculty of Sciences, University of Novi Sad, Trg Dositieja Obradovica 3, 21000 Novi Sad, Serbia
| | - Roman Kaliszan
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Gen. J. Hellera 107, 80-416 Gdańsk, Poland
- Department of Biopharmacy, Collegium Medicum, Nicolaus Copernicus University, Skłodowskiej-Curie 9, 85-094 Bydgoszcz, Poland
| | - Paweł Wiczling
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Gen. J. Hellera 107, 80-416 Gdańsk, Poland
| | - Natasa Milosevic
- Department of Pharmacy, Faculty of Medicine, University of Novi Sad, Hajduk Veljkova 1-3, 21000 Novi Sad, Serbia
| | - Gordana Uscumlic
- Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia
| | - Nebojsa Banjac
- Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia
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25
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Wiczling P, Kaliszan R. Retention time and peak width in the combined pH/organic modifier gradient high performance liquid chromatography. J Chromatogr A 2010; 1217:3375-81. [DOI: 10.1016/j.chroma.2010.03.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 03/01/2010] [Accepted: 03/03/2010] [Indexed: 10/19/2022]
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26
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Kawczak P, Vander Heyden Y, Nasal A, Bączek T, Drabczyñska A, Kieć-Kononowicz K, Kaliszan R. Micellar liquid chromatography for lipophilicity determination of new biologically active 1,3-purinodiones. J Sep Sci 2010; 33:1546-57. [DOI: 10.1002/jssc.200900752] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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27
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Wiczling P, Kaliszan R. pH Gradient as a Tool for the Separation of Ionizable Analytes in Reversed-Phase High-Performance Chromatography. Anal Chem 2010; 82:3692-8. [DOI: 10.1021/ac100023z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Paweł Wiczling
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Gen. J. Hallera 107, 80-416 Gdańsk, Poland
| | - Roman Kaliszan
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Gen. J. Hallera 107, 80-416 Gdańsk, Poland
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28
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QSAR in Chromatography: Quantitative Structure–Retention Relationships (QSRRs). CHALLENGES AND ADVANCES IN COMPUTATIONAL CHEMISTRY AND PHYSICS 2010. [DOI: 10.1007/978-1-4020-9783-6_8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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29
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30
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Nikitas P, Pappa-Louisi A. New Approaches to Linear Gradient Elution Used for Optimization in Reversed-Phase Liquid Chromatography. J LIQ CHROMATOGR R T 2009. [DOI: 10.1080/10826070902956337] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- P. Nikitas
- a Laboratory of Physical Chemistry, Department of Chemistry , Aristotle University of Thessaloniki , Thessaloniki, Greece
| | - A. Pappa-Louisi
- a Laboratory of Physical Chemistry, Department of Chemistry , Aristotle University of Thessaloniki , Thessaloniki, Greece
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31
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Henchoz Y, Bard B, Guillarme D, Carrupt PA, Veuthey JL, Martel S. Analytical tools for the physicochemical profiling of drug candidates to predict absorption/distribution. Anal Bioanal Chem 2009; 394:707-29. [DOI: 10.1007/s00216-009-2634-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 01/16/2009] [Accepted: 01/19/2009] [Indexed: 10/21/2022]
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32
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Wiczling P, Kaliszan R. Influence of pH on Retention in Linear Organic Modifier Gradient RP HPLC. Anal Chem 2008; 80:7855-61. [DOI: 10.1021/ac801093u] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paweł Wiczling
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Gen. J. Hallera 107, 80-416 Gdańsk, Poland
| | - Roman Kaliszan
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Gen. J. Hallera 107, 80-416 Gdańsk, Poland
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33
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Affiliation(s)
- Roman Kaliszan
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Gen. J. Hallera 107, 80416 Gdańsk, Poland.
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34
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O'Gara JE, Wyndham KD. Porous Hybrid Organic‐Inorganic Particles in Reversed‐Phase Liquid Chromatography. J LIQ CHROMATOGR R T 2007. [DOI: 10.1080/10826070600574747] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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35
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Jandera P. Can the theory of gradient liquid chromatography be useful in solving practical problems? J Chromatogr A 2006; 1126:195-218. [PMID: 16787650 DOI: 10.1016/j.chroma.2006.04.094] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Revised: 04/24/2006] [Accepted: 04/28/2006] [Indexed: 10/24/2022]
Abstract
Advances in the theory of gradient liquid chromatography and their practical impacts are reviewed. Theoretical models describing retention in reversed-phase, normal-phase and ion-exchange modes are compared. Main attention is focused on practically useful models described by two- or three-parameter equations fitting the experimental data in the range of mobile phase composition utilized for sample migration during gradient elution. The applications of theory for gradient method development, optimization and transfer are addressed. The origins and possibilities for overcoming possible pitfalls are discussed, including the effects of the instrumental dwell volume, uptake of mobile phase components on the column and size of the sample molecules. Special attention is focused on gradient separations of large molecules.
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Affiliation(s)
- Pavel Jandera
- Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Nám. Cs. Legií 565, CZ-53210 Pardubice, Czech Republic.
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36
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Kowalska S, Krupczyńska K, Buszewski B. The influence of the mobile phase pH and the stationary phase type on the selectivity tuning in high performance liquid chromatography nucleosides separation. J Sep Sci 2006; 28:1502-11. [PMID: 16158992 DOI: 10.1002/jssc.200400044] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Analysis of the modified nucleosides is particularly important in the medical area because of a possibility of cancerogenic processes studies. The aim of this work was to study the selectivity tuning of modified nucleosides through the investigations of interactions analyte (modified nucleoside) <==> stationary phase <==> mobile phase. A series of homemade stationary phases with different surface properties has been utilized. All of them contain various interaction sites such as: cholesterol (SG-CHOL); n-acylamide (SG-CHOL, SG-AP); aminopropyl (SG-CHOL, SG-AP, SG-NH2, SG-MIX); cyanopropyl, phenyl, octyl (SG-MIX), octadecyl (SG-MIX, SG-C18) and silanols localized on the silica gel surface of all packings. The attempt to predict the main interactions responsible for the retention between nucleosides and stationary phase ligands was done on the basis of the elemental analysis, and proportional part of an individual ligand bonded to silica surface results. In order to study the influence of different packing types on the analyzed nucleosides retention, the relationship between pH of the mobile phase buffer and the selectivity of a stationary phase was investigated.
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Affiliation(s)
- Sylwia Kowalska
- Department of Environmental Chemistry and Ecoanalytics, Faculty of Chemistry, Nicolaus Copernicus University, Toruń, Poland
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37
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Torres-Lapasió JR, García-Alvarez-Coque MC. Levels in the interpretive optimisation of selectivity in high-performance liquid chromatography: A magical mystery tour. J Chromatogr A 2006; 1120:308-21. [PMID: 16563407 DOI: 10.1016/j.chroma.2006.03.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2005] [Revised: 03/01/2006] [Accepted: 03/02/2006] [Indexed: 11/26/2022]
Abstract
Interpretive approaches for selectivity optimisation, which are those supported by retention models, are able to exploit efficiently the capabilities of the chromatographic system. The resolution of a mixture is usually faced in a first trial by looking for a unique experimental condition, able to resolve all compounds in the sample. If this is not possible, the problem can be outlined with less ambitious aims, focusing on only some compounds. In an extreme case, a single analyte can be individually optimised. Current strategies that give answer to the different goals pursued in the analysis, which are classified as total, partial and specific, are reviewed. Optimisation oriented to deconvolution, useful in case of partial coelution, and robust measurements of resolution, are also outlined. The steps recognised in any chromatographic optimisation procedure, and some fundamentals and tools used in optimisation approaches for isocratic and gradient elution are commented to explain different strategies. Examples of increasing complexity are supplied to explain the problematic arose, and the convenience in applying a certain methodology. Details on the mathematical treatment for each particular optimisation strategy are also given.
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Affiliation(s)
- J R Torres-Lapasió
- Departament de Química Analítica, Facultat de Química, Universitat de València, c/Dr. Moliner 50, 46100 Burjassot, Spain
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38
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Bolanca T, Cerjan-Stefanović S, Lusa M, Rogosić M, Ukić S. Development of an ion chromatographic gradient retention model from isocratic elution experiments. J Chromatogr A 2006; 1121:228-35. [PMID: 16698028 DOI: 10.1016/j.chroma.2006.04.036] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2005] [Revised: 04/07/2006] [Accepted: 04/10/2006] [Indexed: 10/24/2022]
Abstract
When facing separation problems in ion chromatography, chromatographers often lack guidelines to decide a priori if isocratic elution will give enough separation in a reasonable analysis time or a gradient elution will be required. This situation may be solved by the prediction of retention in gradient elution mode by using isocratic experimental data. This work describes the development of an ion chromatographic gradient elution retention model for fluoride, chloride, nitrite, bromide, nitrate, sulfate and phosphate by using isocratic experimental data. The isocratic elution retention model was developed by applying a polynomial relation between the logarithm of the retention factor and logarithm of the concentration of competing ions; the gradient elution retention model was based on the stepwise numerical integration of the corresponding differential equation. It was shown that the developed gradient elution retention model was not significantly affected by transferring data form isocratic experiment. The root mean squared prediction error for gradient elution retention model was between 0.0863 for fluoride and 0.7027 for bromide proving a very good predictive ability of developed gradient elution retention model.
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Affiliation(s)
- Tomislav Bolanca
- University of Zagreb, Faculty of Chemical Engineering and Technology, Marulićev trg 20, 10000 Zagreb, Croatia.
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39
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Loeser E, Babiak S, Zhu P, Yowell G, Konigsberger M, Drumm P. Automation of pH Optimization Experiments During LC Development. Chromatographia 2006. [DOI: 10.1365/s10337-006-0759-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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40
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Törnblom JK, Bureyko TFW, MacKinnon CD. Simulating phenol high-performance liquid chromatography retention times as the pH changes. J Chromatogr A 2005; 1095:68-73. [PMID: 16275284 DOI: 10.1016/j.chroma.2005.07.115] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2004] [Revised: 06/16/2005] [Accepted: 07/29/2005] [Indexed: 11/30/2022]
Abstract
The HPLC retention times of several substituted phenols have been measured and simulated using Advanced Chemistry Development's LC simulator, using 50% acetonitrile (ACN) as the mobile phase. For alkyl- and nitro-substituted phenols, the quality of the simulation improves when pH of the mobile phase is estimated and used in the simulation. Simply using the pH of the buffer gives simulation results that are not as close to the actual retention times. However, the opposite is the case for halogenated phenols. The pK(a) values in 50% ACN for some of these phenols have also been determined, which tend to be one unit higher than the aqueous pK(a) values reported in the literature.
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Affiliation(s)
- Jon K Törnblom
- Department of Chemistry, Lakehead University, Thunder Bay, Ont., Canada
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41
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Wiczling P, Markuszewski MJ, Kaliszan M, Galer K, Kaliszan R. Combined pH/organic solvent gradient HPLC in analysis of forensic material. J Pharm Biomed Anal 2005; 37:871-5. [PMID: 15862660 DOI: 10.1016/j.jpba.2004.06.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2004] [Revised: 06/29/2004] [Accepted: 06/30/2004] [Indexed: 12/01/2022]
Abstract
A combined pH/organic solvent linear gradient mode in high performance liquid chromatography (HPLC) is presented as a new approach to determination of low concentrations of ionogenic analytes in biological material. The approach consists in simultaneous development of linear gradients of pH and organic modifier in the mobile phase. Advantages of the method are illustrated in postmortem analysis of opipramol in material from suicide victims. Very narrow peaks without tailing were obtained and several times lower limits of analyte quantitation were achieved using ultraviolet detection as compared to a standard isocratic method. The double gradient HPLC method seems to be especially valuable in case of ionogenic analytes dispersed in complex biological matrices. That is due to a high selectivity of the double gradient method and the lack of peak tailing, which is commonly observed for basic analytes chromatographed at isocratic conditions.
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Affiliation(s)
- Paweł Wiczling
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Gen. J. Hallera 107, 80 416 Gdańsk, Poland
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42
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Kaliszan R, Wiczling P. Theoretical opportunities and actual limitations of pH gradient HPLC. Anal Bioanal Chem 2005; 382:718-27. [PMID: 15719233 DOI: 10.1007/s00216-004-3023-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2004] [Revised: 11/29/2004] [Accepted: 12/07/2004] [Indexed: 11/27/2022]
Abstract
In a series of reports published recently by our laboratory comprehensive theory and experimental conditions were established for reversed-phase high-performance liquid chromatography (RP HPLC) employing the programmed pH gradient of mobile phase. A procedure was developed providing, rapidly and conveniently, the acidity (pK(a)) of weak acids and bases and their lipophilicity (hydrophobicity) log k(w). The basis of the double-gradient RP HPLC, employing simultaneous gradients of organic modifier content and mobile phase pH, was also elaborated. The fundamentals of the approach are presented briefly and systematically and its advantages and limitations are discussed. It is demonstrated that the newly introduced pH gradient method increases the analytical versatility of RP HPLC and our understanding of its physicochemical basis.
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Affiliation(s)
- Roman Kaliszan
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Gen. J. Hallera 107, 80-416 Gdańsk, Poland.
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43
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Baczek T. Fractionation of peptides and identification of proteins from Saccharomyces cerevisiae in proteomics with the use of reversed-phase capillary liquid chromatography and pI-based approach. J Pharm Biomed Anal 2005; 35:895-904. [PMID: 15193734 DOI: 10.1016/j.jpba.2004.02.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2003] [Accepted: 02/26/2004] [Indexed: 10/26/2022]
Abstract
The aim of the work was to explore the identification of proteins from Saccharomyces cerevisiae using combined capillary reversed-phase liquid chromatography (RPLC) and in-solution isoelectric focusing (sIEF) for fractionation of peptides prior to mass spectrometry analysis. That method was proved to be the alternative separation method for complex mixtures of protein tryptic digests in proteomics. Analysis of the identification of peptides was performed with the use of electrospray ionization-ion trap tandem mass spectrometry (ESI-IT-MS/MS). First, the sIEF fractionation was carried out prior to separation and mass spectrometry identification by nano-LC/ESI-MS/MS instrument. The proposed approach based on sIEF and nano-LC/ESI-MS/MS analysis was proved to be an efficient and accurate alternative fractionation method of complex protein digests and can be considered as the useful tool for identification of proteins. Moreover, analytical information from that approach can be considered as the additional source of database matching constraint and can be valuable tool for analytical and bioinformatics studies of peptides fractionation in proteomics. Based on the MS/MS results obtained with ESI-IT-MS/MS instrument, 851 proteins from S. cerevisiae were identified. However, after careful analysis of the data reduction in number of proteins to 126 was obtained. Those results are discussed and interpreted in the view of the evaluation method used.
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Affiliation(s)
- Tomasz Baczek
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Gen. J. Hallera 107, 80-416 Gdańsk, Poland.
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44
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Wiczling P, Markuszewski MJ, Kaliszan M, Kaliszan R. pH/Organic Solvent Double-Gradient Reversed-Phase HPLC. Anal Chem 2005; 77:449-58. [PMID: 15649040 DOI: 10.1021/ac049092r] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new reversed-phase high-performance liquid chromatographic (RP HPLC) procedure has been theoretically and experimentally established. The approach consists of the simultaneous development of a gradient of pH and of the organic modifier in the mobile phase. The proposed theoretical model of the pH/organic solvent double-gradient RP HPLC allows determination of both pK(a) and the lipophilicity parameter of the ionized and the nonionized form of the analyte and prediction of the retention times at specific separation conditions as well as bandwidth for all analytes. The model provides a rational basis for optimization of separation of ionizable analytes at any given chromatographic mode and analysis conditions. In addition, in the case of pH/organic solvent double-gradient RP HPLC, a compression of analyte peak and its reduced tailing can be expected.
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Affiliation(s)
- Paweł Wiczling
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Gen. J. Hallera 107, 80-416 Gdańsk, Poland
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45
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Kaliszan R, Wiczling P, Markuszewski MJ. pH gradient high-performance liquid chromatography: theory and applications. J Chromatogr A 2004; 1060:165-75. [PMID: 15628159 DOI: 10.1016/j.chroma.2004.04.081] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
pH gradient high-performance liquid chromatography (HPLC) is a method of reversed-phase high-performance liquid chromatography suitable for ionogenic substances. It consists in programmed increase during the chromatographic process of the eluting strength of eluent with respect to the analytes separated. On the analogy of the conventional organic modifier gradient reversed-phase HPLC, in the pH gradient approach the eluting strength of the mobile phase increases due to its changing pH: increasing in case of acids or decreasing in case of bases. At the same time the content of organic modifier remains constant. A theory of the pH gradient HPLC has been elaborated. The resulting mathematical model is easily manageable. Its ability to predict changes in retention and separation of analytes following the changes in chromatographic conditions is demonstrated. The pH gradient method is uniquely suitable to determine pKa values of analytes. An equation is presented allowing to calculate pKa values basing on appropriate retention data. The effects on pKa are discussed of the concentration of methanol in the mobile phase. The RP HPLC-derived pKa data correlate to the reference pKa values (w(w)pKa) but are not identical. That may be explained by the effects on the chromatographically determined pKa of the specific interactions of analytes with stationary phases. The proposed pH gradient RP HPLC procedure offers a fast and convenient means to get comparable acidity parameters for larger series of compounds, like drug candidates, also when the analytes are available only in minute amounts and/or as complex mixtures.
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Affiliation(s)
- Roman Kaliszan
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Gen. J. Hallera 107, Gdańsk 80-416, Poland.
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46
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Jandera P, Blomberg LG, Lundanes E. Controlling the retention in capillary LC with solvents, temperature, and electric fields. J Sep Sci 2004; 27:1402-18. [PMID: 15638149 DOI: 10.1002/jssc.200401852] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Once a suitable stationary phase and column dimensions have been selected, the retention in liquid chromatography (LC) is traditionally adjusted by controlling the mobile phase composition. Solvent gradients enable achievement of good separation selectivity while decreasing the separation time as compared to isocratic elution. Capillary columns allow use of other programming parameters, i.e. temperature and applied electric fields, in addition to solvent gradient elution. This paper presents a review of programmed separation techniques in miniaturized LC, including retention modeling and method transfer from the conventional to micro- and capillary scales. The impact of miniaturized instrumentation on retention and the limitations of capillary LC are discussed. Special attention is focused on the gradient dwell volume effects, which are more important in micro-LC techniques than in conventional analytical LC and may cause significant increase in the time of analysis, unless special instrumentation and (or) pre-column flow-splitting is used. The influence of temperature upon retention is also discussed, and applications where the temperature has been actively used for retention control in capillary LC are included together with the instrumentation utilized. Finally the possibilities of additional selectivity control by applying an electric field over a packed capillary LC column are discussed.
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Affiliation(s)
- Pavel Jandera
- Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice Nám Cs legii 565, CZ 532 10 Pardubice, Czech Republic
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47
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Wiczling P, Markuszewski MJ, Kaliszan R. Determination of pKa by pH Gradient Reversed-Phase HPLC. Anal Chem 2004; 76:3069-77. [PMID: 15167784 DOI: 10.1021/ac049807q] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
pH gradient reversed-phase HPLC consists of a programmed increase during the chromatographic run of the eluting power of the mobile phase with regard to ionizable analytes. On the analogy of the conventional organic modifier gradient RP HPLC, in the pH gradient mode, the eluting strength of the mobile phase increases due to its increasing (with acid analytes) or decreasing (with basic analytes) pH, whereas the content of organic modifier is kept constant. We have shown previously that the pH gradient separations are technically possible using standard chromatographic equipment. Here we demonstrate that the method is uniquely suitable to determine pK(a) values of analytes. A strict theoretical model is proposed to determine pK(a) values based on the retention data from a pH gradient RP HPLC run. The pK(a) data so obtained are discussed in relation to the concentration of methanol in the mobile phase, the type of stationary phase, and the duration of the gradient. The pK(a) values determined by the pH gradient method are related to the respective data obtained conventionally in a series of isocratic experiments. A close similarity of the two types of chromatographically determined pK(a) data is demonstrated. The HPLC-derived pK(a) parameters correlate to the literature pK(a) values determined by titrations in water. The chromatographically derived and the reference pK(a) values are not identical, however. That is probably due to the effects on the chromatographic pK(a) of the specific sites of interactions with analytes on the surfaces of the HPLC stationary phases. Nonetheless, the proposed pH gradient HPLC method may supply in a fast and convenient manner comparable acidity parameters for larger series of drug candidates, including those available in only minute amounts, without need of their purification, and also when the compounds are provided as complex mixtures, like those produced by combinatorial chemistry.
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Affiliation(s)
- Paweł Wiczling
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Gen. J. Hallera 107, 80-416 Gdansk, Poland
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