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Identification of Epigallocatechin-3-Gallate (EGCG) from Green Tea Using Mass Spectrometry. SEPARATIONS 2022. [DOI: 10.3390/separations9080209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In an era where humanity is reinstating its lost hope and expectation on natural products, green tea occupies quite a position for what it has proven to be, in its endeavors for human welfare and health. Epigallocatechin-3-gallate (EGCG) is the key to the vast biological activities of green tea. Green tea is no longer in the backdrop; it has emerged as the most viral, trending bioactive molecule when it comes to health benefits for human beings. This review focuses on the use of various analytical techniques for the analysis of EGCG. That which has been achieved so far, in terms of in vitro, pure component analysis, as well as those spikes in biological fluids and those in vivo in animal and human samples, was surveyed and presented. The use of MS-based techniques for the analysis of EGCG is elaborately reviewed and the need for improvising the applications is explained. The review emphasizes that there is plenty of room to explore matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) applications in this subject area.
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Liu Z, Zhang P, Pyttlik A, Kraus T, Volmer DA. Influence of core size and capping ligand of gold nanoparticles on the desorption/ionization efficiency of small biomolecules in AP‐SALDI‐MS. ACTA ACUST UNITED AC 2020. [DOI: 10.1002/ansa.202000002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Zhen Liu
- Institute of Bioanalytical Chemistry Saarland University Saarbrücken Germany
| | - Peng Zhang
- School of Materials Science and Engineering Sun Yat‐sen University Guangzhou China
| | - Andrea Pyttlik
- INM‐Leibniz Institute for New Materials Saarbrücken Germany
| | - Tobias Kraus
- INM‐Leibniz Institute for New Materials Saarbrücken Germany
- Institute of Colloid and Interface Chemistry Saarland University Saarbrücken Germany
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3
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Gogichaeva NV, Alterman MA. Amino Acid Analysis by Means of MALDI TOF Mass Spectrometry or MALDI TOF/TOF Tandem Mass Spectrometry. Methods Mol Biol 2019; 2030:17-31. [PMID: 31347107 DOI: 10.1007/978-1-4939-9639-1_3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Here we describe two different AAA protocols based on application of matrix-assisted laser desorption ionization time-of-flight (MALDI TOF) mass spectrometry (MS). First protocol describes a MALDI TOF MS-based method for a routine simultaneous qualitative and quantitative analysis of free amino acids and protein hydrolysates. Linear responses between the amino acid concentration and the peak intensity ratio of corresponding amino acid to internal standard were observed for all amino acids analyzed in the range of concentrations from 20 to 300 μM. Limit of quantitation varied from 0.03 μM for arginine to 3.7 μM for histidine and homocysteine. This method has one inherent limitation: the analysis of isomeric and isobaric amino acids. To solve this problem, a second protocol based on the use of MALDI TOF/TOF MS/MS for qualitative analysis of amino and organic acids was developed. This technique is capable of distinguishing isobaric and isomeric compounds. Both methods do not require amino acid derivatization or chromatographic separation, and the data acquisition time is decreased to several seconds for a single sample.
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Affiliation(s)
| | - Michail A Alterman
- Office of Policy for Pharmaceutical Quality, Office of Pharmaceutical Quality, Center for Drug Evaluation and Research, US FDA, Silver Spring, MD, USA.
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4
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Rzagalinski I, Volmer DA. Quantification of low molecular weight compounds by MALDI imaging mass spectrometry - A tutorial review. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1865:726-739. [PMID: 28012871 DOI: 10.1016/j.bbapap.2016.12.011] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 12/01/2016] [Accepted: 12/19/2016] [Indexed: 10/20/2022]
Abstract
Matrix-assisted laser desorption/ionization (MALDI)-mass spectrometry imaging (MSI) permits label-free in situ analysis of chemical compounds directly from the surface of two-dimensional biological tissue slices. It links qualitative molecular information of compounds to their spatial coordinates and distribution within the investigated tissue. MALDI-MSI can also provide the quantitative amounts of target compounds in the tissue, if proper calibration techniques are performed. Obviously, as the target molecules are embedded within the biological tissue environment and analysis must be performed at their precise locations, there is no possibility for extensive sample clean-up routines or chromatographic separations as usually performed with homogenized biological materials; ion suppression phenomena therefore become a critical side effect of MALDI-MSI. Absolute quantification by MALDI-MSI should provide an accurate value of the concentration/amount of the compound of interest in relatively small, well-defined region of interest of the examined tissue, ideally in a single pixel. This goal is extremely challenging and will not only depend on the technical possibilities and limitations of the MSI instrument hardware, but equally on the chosen calibration/standardization strategy. These strategies are the main focus of this article and are discussed and contrasted in detail in this tutorial review. This article is part of a Special Issue entitled: MALDI Imaging, edited by Dr. Corinna Henkel and Prof. Peter Hoffmann.
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Affiliation(s)
- Ignacy Rzagalinski
- Institute of Bioanalytical Chemistry, Saarland University, 66123 Saarbrücken, Germany
| | - Dietrich A Volmer
- Institute of Bioanalytical Chemistry, Saarland University, 66123 Saarbrücken, Germany.
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Silina YE, Koch M, Volmer DA. Influence of surface melting effects and availability of reagent ions on LDI-MS efficiency after UV laser irradiation of Pd nanostructures. JOURNAL OF MASS SPECTROMETRY : JMS 2015; 50:578-585. [PMID: 25800194 DOI: 10.1002/jms.3564] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 12/09/2014] [Accepted: 12/10/2014] [Indexed: 06/04/2023]
Abstract
In this study, the influence of surface morphology, reagent ions and surface restructuring effects on atmospheric pressure laser desorption/ionization (LDI) for small molecules after laser irradiation of palladium self-assembled nanoparticular (Pd-NP) structures has been systematically studied. The dominant role of surface morphology during the LDI process, which was previously shown for silicon-based substrates, has not been investigated for metal-based substrates before. In our experiments, we demonstrated that both the presence of reagent ions and surface reorganization effects--in particular, melting--during laser irradiation was required for LDI activity of the substrate. The synthesized Pd nanostructures with diameters ranging from 60 to 180 nm started to melt at similar temperatures, viz. 890-898 K. These materials exhibited different LDI efficiencies, however, with Pd-NP materials being the most effective surface in our experiments. Pd nanostructures of diameters >400-800 nm started to melt at higher temperatures, >1000 K, making such targets more resistant to laser irradiation, with subsequent loss of LDI activity. Our data demonstrated that both melting of the surface structures and the presence of reagent ions were essential for efficient LDI of the investigated low molecular weight compounds. This dependence of LDI on melting points was exploited further to improve the performance of Pd-NP-based sampling targets. For example, adding sodium hypophosphite as reducing agent to Pd electrolyte solutions during synthesis lowered the melting points of the Pd-NP materials and subsequently gave reduced laser fluence requirements for LDI.
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Affiliation(s)
- Yuliya E Silina
- Leibniz Institute of New Materials (INM), Saarbrücken, Germany; Institute of Bioanalytical Chemistry, Saarland University, Saarbrücken, Germany
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6
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Gode D, Schmitt C, Engel M, Volmer DA. Screening Dyrk1A inhibitors by MALDI-QqQ mass spectrometry: systematic comparison to established radiometric, luminescence, and LC-UV-MS assays. Anal Bioanal Chem 2014; 406:2841-52. [PMID: 24618988 DOI: 10.1007/s00216-014-7703-1] [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: 12/17/2013] [Revised: 02/12/2014] [Accepted: 02/17/2014] [Indexed: 11/26/2022]
Abstract
Enzyme-catalyzed reactions play key roles in disease pathology, thus making them relevant subjects of therapeutic inhibitor screening experiments. Matrix-assisted laser desorption/ionization (MALDI) assays have been demonstrated to be able to replace established screening approaches. They offer increased sample throughput, but care must be taken to avoid instrumental bias from differences in ionization efficiencies. We compared a MALDI-triple-quadrupole (QqQ) method for the Dyrk1A peptide substrate woodtide to LC-MS, liquid chromatography with ultraviolet detection (LC-UV), luminescence, and radiometric assays. MALDI measurements were performed on a MALDI-QqQ instrument in the multiple-reaction monitoring mode. Different MALDI conditions were investigated to address whether matrix type, sample support, and MRM- or SIM-based detection conditions can be used to accommodate the molar responses of substrate peptide and its phosphorylated form. UV detection served as a reference method. The impact of MALDI matrix on IC50 values was small, even considering that matrix preparations were used that are known to alleviate response differences. IC50 values determined by MALDI were ca. 2-fold lower than those determined by LC-UV. Although MALDI generated lower ion yields for the phosphorylated peptide than for the peptide substrate, we found that a correction of compound potencies was readily possible using correction factors based on unbiased LC-UV results. A thorough method development delivered a robust assay with excellent performance (Z' > 0.91) that was close to that seen for LC-UV.
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Affiliation(s)
- David Gode
- Institute of Bioanalytical Chemistry, Saarland University, 66123, Saarbrücken, Germany
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7
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High-throughput receptor-based assay for the detection of spirolides by chemiluminescence. Toxicon 2013; 75:35-43. [DOI: 10.1016/j.toxicon.2013.06.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 06/13/2013] [Accepted: 06/21/2013] [Indexed: 11/18/2022]
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Pabst M, Fagerer SR, Köhling R, Küster SK, Steinhoff R, Badertscher M, Wahl F, Dittrich PS, Jefimovs K, Zenobi R. Self-Aliquoting Microarray Plates for Accurate Quantitative Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry. Anal Chem 2013; 85:9771-6. [DOI: 10.1021/ac4021775] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Martin Pabst
- Department
of Chemistry and Applied Biosciences, ETH Zürich, Wolfgang-Pauli-Strasse
10, 8093 Zürich, Switzerland
| | - Stephan R. Fagerer
- Department
of Chemistry and Applied Biosciences, ETH Zürich, Wolfgang-Pauli-Strasse
10, 8093 Zürich, Switzerland
| | - Rudolf Köhling
- Sigma-Aldrich, Industriestrasse 25, 9471 Buchs, Switzerland
| | - Simon K. Küster
- Department
of Chemistry and Applied Biosciences, ETH Zürich, Wolfgang-Pauli-Strasse
10, 8093 Zürich, Switzerland
| | - Robert Steinhoff
- Department
of Chemistry and Applied Biosciences, ETH Zürich, Wolfgang-Pauli-Strasse
10, 8093 Zürich, Switzerland
| | - Martin Badertscher
- Department
of Chemistry and Applied Biosciences, ETH Zürich, Wolfgang-Pauli-Strasse
10, 8093 Zürich, Switzerland
| | - Fabian Wahl
- Sigma-Aldrich, Industriestrasse 25, 9471 Buchs, Switzerland
| | - Petra S. Dittrich
- Department
of Chemistry and Applied Biosciences, ETH Zürich, Wolfgang-Pauli-Strasse
10, 8093 Zürich, Switzerland
| | - Konstantins Jefimovs
- Swiss Federal Laboratories for Material Science and Technology EMPA, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Renato Zenobi
- Department
of Chemistry and Applied Biosciences, ETH Zürich, Wolfgang-Pauli-Strasse
10, 8093 Zürich, Switzerland
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Gode D, Volmer DA. A novel magnet focusing plate for matrix-assisted laser desorption/ionization analysis of magnetic bead-bound analytes. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2013; 27:1011-1018. [PMID: 23592204 DOI: 10.1002/rcm.6548] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 02/14/2013] [Accepted: 02/14/2013] [Indexed: 06/02/2023]
Abstract
RATIONALE Magnetic beads are often used for serum profiling of peptide and protein biomarkers. In these assays, the bead-bound analytes are eluted from the beads prior to mass spectrometric analysis. This study describes a novel matrix-assisted laser desorption/ionization (MALDI) technique for direct application and focusing of magnetic beads to MALDI plates by means of dedicated micro-magnets as sample spots. METHODS Custom-made MALDI plates with magnetic focusing spots were made using small nickel-coated neodymium micro-magnets integrated into a stainless steel plate in a 16 × 24 (384) pattern. For demonstrating the proof-of-concept, commercial C-18 magnetic beads were used for the extraction of a test compound (reserpine) from aqueous solution. Experiments were conducted to study focusing abilities, the required laser energies, the influence of a matrix compound, dispensing techniques, solvent choice and the amount of magnetic beads. RESULTS Dispensing the magnetic beads onto the micro-magnet sample spots resulted in immediate and strong binding to the magnetic surface. Light microscope images illustrated the homogeneous distribution of beads across the surfaces of the magnets, when the entire sample volume containing the beads was pipetted onto the surface. Subsequent MALDI analysis of the bead-bound analyte demonstrated excellent and reproducible ionization yields. The surface-assisted laser desorption/ionization (SALDI) properties of the strongly light-absorbing γ-Fe2O3-based beads resulted in similar ionization efficiencies to those obtained from experiments with an additional MALDI matrix compound. CONCLUSIONS This feasibility study successfully demonstrated the magnetic focusing abilities for magnetic bead-bound analytes on a novel MALDI plate containing small micro-magnets as sample spots. One of the key advantages of this integrated approach is that no elution steps from magnetic beads were required during analyses compared with conventional bead experiments.
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Affiliation(s)
- David Gode
- Institute of Bioanalytical Chemistry, Saarland University, Saarbrücken, Germany
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10
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Rodríguez LP, Vilariño N, Molgó J, Aráoz R, Louzao MC, Taylor P, Talley T, Botana LM. Development of a solid-phase receptor-based assay for the detection of cyclic imines using a microsphere-flow cytometry system. Anal Chem 2013; 85:2340-7. [PMID: 23343192 PMCID: PMC3597463 DOI: 10.1021/ac3033432] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Biologically active macrocycles containing a cyclic imine were isolated for the first time from aquaculture sites in Nova Scotia, Canada, during the 1990s. These compounds display a "fast-acting" toxicity in the traditional mouse bioassay for lipophilic marine toxins. Our work aimed at developing a receptor-based detection method for spirolides using a microsphere/flow cytometry Luminex system. For the assay, two alternatives were considered as binding proteins, the Torpedo marmorata nicotinic acetylcholine receptor (nAChR) and the Lymnaea stagnalis acetylcholine binding protein (Ls-AChBP). A receptor-based inhibition assay was developed using the immobilization of nAChR or Ls-AChBP on the surface of carboxylated microspheres and the competition of cyclic imines with biotin-α-bungarotoxin (α-BTX) for binding to these proteins. The amount of biotin-α-BTX bound to the surface of the microspheres was quantified using phycoerythrin (PE)-labeled streptavidin, and the fluorescence was analyzed in a Luminex 200 system. AChBP and nAChR bound to 13-desmethyl spirolide C efficiently; however, the cross-reactivity profile of the nAChR for spirolides and gymnodimine more closely matched the relative toxic potencies reported for these toxins. The nAChR was selected for further assay development. A simple sample preparation protocol consisting of an extraction with acetone yielded a final extract with no matrix interference on the nAChR/microsphere-based assay for mussels, scallops, and clams. This cyclic imine detection method allowed the detection of 13-desmethyl spirolide C in the range of 10-6000 μg/kg of shellfish meat, displaying a higher sensitivity and wider dynamic range than other receptor-based assays previously published. This microsphere-based assay provides a rapid, sensitive, and easily performed screening method that could be multiplexed for the simultaneous detection of several marine toxins.
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Affiliation(s)
- Laura P. Rodríguez
- Universidad de Santiago de Compostela, Departamento de Farmacología, Facultad de Veterinaria, 27002 Lugo, Spain
| | - Natalia Vilariño
- Universidad de Santiago de Compostela, Departamento de Farmacología, Facultad de Veterinaria, 27002 Lugo, Spain
| | - Jordi Molgó
- CNRS, Institut de Neurobiologie Alfred Fessard FRC2118, Laboratoire de Neurobiologie et Développement UPR3294, 91198 Gif-sur-Yvette Cedex, France
| | - Rómulo Aráoz
- CNRS, Institut de Neurobiologie Alfred Fessard FRC2118, Laboratoire de Neurobiologie et Développement UPR3294, 91198 Gif-sur-Yvette Cedex, France
| | - M. Carmen Louzao
- Universidad de Santiago de Compostela, Departamento de Farmacología, Facultad de Veterinaria, 27002 Lugo, Spain
| | - Palmer Taylor
- Department of Pharmacology, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California at San Diego, La Jolla, CA, USA
| | - Todd Talley
- Department of Pharmacology, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California at San Diego, La Jolla, CA, USA
| | - Luis M. Botana
- Universidad de Santiago de Compostela, Departamento de Farmacología, Facultad de Veterinaria, 27002 Lugo, Spain
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Aráoz R, Ramos S, Pelissier F, Guérineau V, Benoit E, Vilariño N, Botana LM, Zakarian A, Molgó J. Coupling the Torpedo microplate-receptor binding assay with mass spectrometry to detect cyclic imine neurotoxins. Anal Chem 2012; 84:10445-53. [PMID: 23131021 PMCID: PMC4118673 DOI: 10.1021/ac3027564] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cyclic imine neurotoxins constitute an emergent family of neurotoxins of dinoflagellate origin that are potent antagonists of nicotinic acetylcholine receptors. We developed a target-directed functional method based on the mechanism of action of competitive agonists/antagonists of nicotinic acetylcholine receptors for the detection of marine cyclic imine neurotoxins. The key step for method development was the immobilization of Torpedo electrocyte membranes rich in nicotinic acetylcholine receptors on the surface of microplate wells and the use of biotinylated-α-bungarotoxin as tracer. Cyclic imine neurotoxins competitively inhibit biotinylated-α-bungarotoxin binding to Torpedo-nicotinic acetylcholine receptors in a concentration-dependent manner. The microplate-receptor binding assay allowed rapid detection of nanomolar concentrations of cyclic imine neurotoxins directly in shellfish samples. Although highly sensitive and specific for the detection of neurotoxins targeting nicotinic acetylcholine receptors as a class, the receptor binding assay cannot identify a given analyte. To address the low selectivity of the microplate-receptor binding assay, the cyclic imine neurotoxins tightly bound to the coated Torpedo nicotinic receptor were eluted with methanol, and the chemical nature of the eluted ligands was identified by mass spectrometry. The immobilization of Torpedo electrocyte membranes on the surface of microplate wells proved to be a high-throughput format for the survey of neurotoxins targeting nicotinic acetylcholine receptors directly in shellfish matrixes with high sensitivity and reproducibility.
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Affiliation(s)
- Rómulo Aráoz
- Centre de Recherche CNRS de Gif-sur-Yvette, Institut Fédératif de Neurobiologie Alfred Fessard FR2118, Laboratoire de Neurobiologie et Développement UPR 3294, 91198 Gif sur Yvette, France
| | - Suzanne Ramos
- Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif sur Yvette, France
| | - Franck Pelissier
- Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif sur Yvette, France
| | - Vincent Guérineau
- Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif sur Yvette, France
| | - Evelyne Benoit
- Centre de Recherche CNRS de Gif-sur-Yvette, Institut Fédératif de Neurobiologie Alfred Fessard FR2118, Laboratoire de Neurobiologie et Développement UPR 3294, 91198 Gif sur Yvette, France
| | - Natalia Vilariño
- Departamento de Farmacología, Facultad de Veterinaria, Campus Universitario, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Luis M. Botana
- Departamento de Farmacología, Facultad de Veterinaria, Campus Universitario, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Armen Zakarian
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, United States
| | - Jordi Molgó
- Centre de Recherche CNRS de Gif-sur-Yvette, Institut Fédératif de Neurobiologie Alfred Fessard FR2118, Laboratoire de Neurobiologie et Développement UPR 3294, 91198 Gif sur Yvette, France
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Shi T, Su D, Liu T, Tang K, Camp DG, Qian WJ, Smith RD. Advancing the sensitivity of selected reaction monitoring-based targeted quantitative proteomics. Proteomics 2012; 12:1074-92. [PMID: 22577010 PMCID: PMC3375056 DOI: 10.1002/pmic.201100436] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 01/12/2012] [Indexed: 12/13/2022]
Abstract
Selected reaction monitoring (SRM) - also known as multiple reaction monitoring (MRM) - has emerged as a promising high-throughput targeted protein quantification technology for candidate biomarker verification and systems biology applications. A major bottleneck for current SRM technology, however, is insufficient sensitivity for, e.g. detecting low-abundance biomarkers likely present at the low ng/mL to pg/mL range in human blood plasma or serum, or extremely low-abundance signaling proteins in cells or tissues. Herein, we review recent advances in methods and technologies, including front-end immunoaffinity depletion, fractionation, selective enrichment of target proteins/peptides including posttranslational modifications, as well as advances in MS instrumentation which have significantly enhanced the overall sensitivity of SRM assays and enabled the detection of low-abundance proteins at low- to sub-ng/mL level in human blood plasma or serum. General perspectives on the potential of achieving sufficient sensitivity for detection of pg/mL level proteins in plasma are also discussed.
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Affiliation(s)
- Tujin Shi
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Dian Su
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Tao Liu
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Keqi Tang
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352
| | - David G. Camp
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Wei-Jun Qian
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Richard D. Smith
- Biological Sciences Division and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352
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13
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Amino acid analysis by means of MALDI TOF mass spectrometry or MALDI TOF/TOF tandem mass spectrometry. Methods Mol Biol 2012; 828:121-35. [PMID: 22125142 DOI: 10.1007/978-1-61779-445-2_12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Here, we describe two different amino acid analysis protocols based on the application of matrix-assisted laser desorption ionization time-of-flight (MALDI TOF) mass spectrometry (MS). First protocol describes a MALDI TOF MS-based method for a routine simultaneous qualitative and quantitative analysis of free amino acids and protein hydrolysates (Alterman et al. Anal Biochem 335: 184-191, 2004). Linear responses between the amino acid concentration and the peak intensity ratio of corresponding amino acid to internal standard were observed for all amino acids analyzed in the range of concentrations from 20 to 300 μM. Limit of quantitation varied from 0.03 μM for arginine to 3.7 μM for histidine and homocysteine. This method has one inherent limitation: the analysis of isomeric and isobaric amino acids. To solve this problem, a second protocol based on the use of MALDI TOF/TOF MS/MS for qualitative analysis of amino and organic acids was developed. This technique is capable of distinguishing isobaric and isomeric compounds (Gogichayeva et al. J Am Soc Mass Spectrom 18: 279-284, 2007). Both methods do not require amino acid derivatization or chromatographic separation, and the data acquisition time is decreased to several seconds for a single sample.
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14
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Rodríguez LP, Vilariño N, Molgó J, Aráoz R, Antelo A, Vieytes MR, Botana LM. Solid-Phase Receptor-Based Assay for the Detection of Cyclic Imines by Chemiluminescence, Fluorescence, or Colorimetry. Anal Chem 2011; 83:5857-63. [DOI: 10.1021/ac200423s] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Laura P. Rodríguez
- Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Natalia Vilariño
- Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Jordi Molgó
- CNRS, Institut Fédératif de Neurobiologie Alfred Fessard—FRC2118, Laboratoire de Neurobiologie et Développement—UPR3294, 91198 Gif sur Yvette cedex, France
| | - Rómulo Aráoz
- CNRS, Institut Fédératif de Neurobiologie Alfred Fessard—FRC2118, Laboratoire de Neurobiologie et Développement—UPR3294, 91198 Gif sur Yvette cedex, France
| | - Alvaro Antelo
- CIFGA Laboratorio, Plaza de Santo Domingo, 20, 5a planta, 27001 Lugo, Spain
| | - Mercedes R. Vieytes
- Departamento de Fisiología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Luis M. Botana
- Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
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15
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Szyszka R, Hanton SD, Henning D, Owens KG. Development of a combined standard additions/internal standards method to quantify residual PEG in ethoxylated surfactants by MALDI TOFMS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2011; 22:633-640. [PMID: 21472602 DOI: 10.1007/s13361-010-0065-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 12/21/2010] [Accepted: 12/21/2010] [Indexed: 05/30/2023]
Abstract
Measuring the residual polyethylene glycol (PEG) in polyethylene oxide (PEO)-based surfactants is important to fully understanding the performance of these materials. Traditional methods of quantitating PEG in PEO-based surfactants can be time-consuming and struggle with low amounts or overlapping molecular mass distributions. This paper describes a matrix-assisted laser desorption/ionization (MALDI) mass spectrometry method developed to quantitate residual PEG in a series of ethoxylated surfactants. The technique addresses the difficulties faced in doing quantitative MALDI experiments by utilizing both internal standard and standard additions protocols. The method produces excellent straight line standard addition plots, and the quantitative results are verified using both a constructed standard and an independent traditional chromatographic separation.
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Affiliation(s)
- Renata Szyszka
- Department of Chemistry, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
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van Kampen JJA, Burgers PC, de Groot R, Gruters RA, Luider TM. Biomedical application of MALDI mass spectrometry for small-molecule analysis. MASS SPECTROMETRY REVIEWS 2011; 30:101-120. [PMID: 20169623 DOI: 10.1002/mas.20268] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is an emerging analytical tool for the analysis of molecules with molar masses below 1,000 Da; that is, small molecules. This technique offers rapid analysis, high sensitivity, low sample consumption, a relative high tolerance towards salts and buffers, and the possibility to store sample on the target plate. The successful application of the technique is, however, hampered by low molecular weight (LMW) matrix-derived interference signals and by poor reproducibility of signal intensities during quantitative analyses. In this review, we focus on the biomedical application of MALDI-MS for the analysis of small molecules and discuss its favorable properties and its challenges as well as strategies to improve the performance of the technique. Furthermore, practical aspects and applications are presented.
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Affiliation(s)
- Jeroen J A van Kampen
- Laboratories of Neuro-Oncology/Clinical and Cancer Proteomics, Department of Neurology, Erasmus MC, Rotterdam, The Netherlands
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Otero P, Alfonso A, Alfonso C, Vieytes MR, Louzao MC, Botana AM, Botana LM. New protocol to obtain spirolides from Alexandrium ostenfeldii cultures with high recovery and purity. Biomed Chromatogr 2010; 24:878-86. [PMID: 20087843 DOI: 10.1002/bmc.1380] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The aim of this work was to develop a method to purify large amounts of spirolide toxins from cultures of Alexandrium ostenfeldii. The dinoflagellates grew in batches under controlled conditions of salinity, light and temperature. Analysis of the cultures demonstrated the existence of neurotoxins associated with paralytic shellfish poisoning toxins and two spirolides, 13-desmethyl spirolide C and 13,19-didesmethyl spirolide C. The protocol designed presents several stages of extraction, separation between spirolides and paralytic shellfish poisoning toxins, and cleanup in solid-phase extraction. Finally, the purification of spirolides was conducted by a preparative high-performance liquid chromatography system coupled to a mass spectrometer detector. The purity and the amount of both toxins in each step was monitored by analytical liquid chromatographic-mass spectrometry. Large amounts of 13-desMeC, 97% pure, and 13,19-didesMeC, 99% pure, were obtained. A novel and efficient method to separate and purify spirolide toxins from large amounts of phytoplankton is provided. The protocol proposed shows, for the first time, a complete and detailed methodology to separate and purify spirolide toxins with high purity, recovery, repeatability and stability.
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Affiliation(s)
- Paz Otero
- Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
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A new ultrafast and high-throughput mass spectrometric approach for the therapeutic drug monitoring of the multi-targeted anti-folate pemetrexed in plasma from lung cancer patients. Anal Bioanal Chem 2010; 398:2943-8. [PMID: 20865407 PMCID: PMC2990004 DOI: 10.1007/s00216-010-4192-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 09/01/2010] [Accepted: 09/02/2010] [Indexed: 11/15/2022]
Abstract
An analytical assay has been developed and validated for ultrafast and high-throughput mass spectrometric determination of pemetrexed concentrations in plasma using matrix assisted laser desorption/ionization–triple quadrupole–tandem mass spectrometry. Patient plasma samples spiked with the internal standard methotrexate were measured by multiple reaction monitoring. The detection limit was 0.4 fmol/μL, lower limit of quantification was 0.9 fmol/μL, and upper limit of quantification was 60 fmol/μL, respectively. Overall observed pemetrexed concentrations in patient samples ranged between 8.7 (1.4) and 142.7 (20.3) pmol/μL (SD). The newly developed mass spectrometric assay is applicable for (routine) therapeutic drug monitoring of pemetrexed concentrations in plasma from non-small cell lung cancer patients.
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19
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van Kampen JJA, Reedijk ML, Burgers PC, Dekker LJM, Hartwig NG, van der Ende IE, de Groot R, Osterhaus ADME, Burger DM, Luider TM, Gruters RA. Ultra-fast analysis of plasma and intracellular levels of HIV protease inhibitors in children: a clinical application of MALDI mass spectrometry. PLoS One 2010; 5:e11409. [PMID: 20625386 PMCID: PMC2895665 DOI: 10.1371/journal.pone.0011409] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Accepted: 05/11/2010] [Indexed: 01/03/2023] Open
Abstract
HIV protease inhibitors must penetrate into cells to exert their action. Differences in the intracellular pharmacokinetics of these drugs may explain why some patients fail on therapy or suffer from drug toxicity. Yet, there is no information available on the intracellular levels of HIV protease inhibitors in HIV infected children, which is in part due to the large amount of sample that is normally required to measure the intracellular concentrations of these drugs. Therefore, we developed an ultra-fast and sensitive assay to measure the intracellular concentrations of HIV protease inhibitors in small amounts of peripheral blood mononuclear cells (PBMCs), and determined the intracellular concentrations of lopinavir and ritonavir in HIV infected children. An assay based on matrix-assisted laser desorption/ionization (MALDI) - triple quadrupole mass spectrometry was developed to determine the concentrations of HIV protease inhibitors in 10 µL plasma and 1×106 PBMCs. Precisions and accuracies were within the values set by the FDA for bioanalytical method validation. Lopinavir and ritonavir did not accumulate in PBMCs of HIV infected children. In addition, the intracellular concentrations of lopinavir and ritonavir correlated poorly to the plasma concentrations of these drugs. MALDI-triple quadrupole mass spectrometry is a new tool for ultra-fast and sensitive determination of drug concentrations which can be used, for example, to assess the intracellular pharmacokinetics of HIV protease inhibitors in HIV infected children.
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Affiliation(s)
- Jeroen J. A. van Kampen
- Department of Neurology, Erasmus MC, Rotterdam, The Netherlands
- Department of Paediatrics, Erasmus MC – Sophia, Rotterdam, The Netherlands
- Department of Virology, Erasmus MC, Rotterdam, The Netherlands
| | | | | | | | - Nico G. Hartwig
- Department of Paediatrics, Erasmus MC – Sophia, Rotterdam, The Netherlands
| | | | - Ronald de Groot
- Department of Paediatrics, University Medical Centre Nijmegen, Nijmegen, The Netherlands
| | | | - David M. Burger
- Department of Clinical Pharmacy, University Medical Centre Nijmegen, Nijmegen, The Netherlands
| | - Theo M. Luider
- Department of Neurology, Erasmus MC, Rotterdam, The Netherlands
- * E-mail:
| | - Rob A. Gruters
- Department of Virology, Erasmus MC, Rotterdam, The Netherlands
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Guéret SM, Brimble MA. Spiroimine shellfish poisoning (SSP) and the spirolide family of shellfish toxins: isolation, structure, biological activity and synthesis. Nat Prod Rep 2010; 27:1350-66. [PMID: 20585694 DOI: 10.1039/c005400n] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Scientific Opinion on marine biotoxins in shellfish – Cyclic imines (spirolides, gymnodimines, pinnatoxins and pteriatoxins). EFSA J 2010. [DOI: 10.2903/j.efsa.2010.1628] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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22
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Fonfría ES, Vilariño N, Espiña B, Louzao MC, Álvarez M, Molgó J, Aráoz R, Botana LM. Feasibility of gymnodimine and 13-desmethyl C spirolide detection by fluorescence polarization using a receptor-based assay in shellfish matrixes. Anal Chim Acta 2010; 657:75-82. [DOI: 10.1016/j.aca.2009.10.027] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Revised: 08/27/2009] [Accepted: 10/13/2009] [Indexed: 11/16/2022]
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23
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Koulman A, Petras D, Narayana VK, Wang L, Volmer DA. Comparative high-speed profiling of carboxylic acid metabolite levels by differential isotope-coded MALDI mass spectrometry. Anal Chem 2009; 81:7544-51. [PMID: 19702295 DOI: 10.1021/ac900562j] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This present work describes the development of a novel high throughput comparative matrix-assisted laser desorption ionization (MALDI) mass spectrometry profiling technique for endogenous compounds using a new isotope-coded label for relative quantitation of carboxylic acids. The key new aspect of this technique was a differential label, 3-hydroxymethyl-1-ethylpyrididinium iodide (HMEP), designed specifically for simultaneous quantitative MALDI analysis of two physiological states. The HMEP-d(0) and HMEP-d(5) variants of the label were applied to profiling endogenous fatty acid levels during a fish oil intervention study, using the metabolite profile of every individual person in the study as their own personal analytical reference standard. Initially, analytical figures of merit such as sensitivity, linear dynamic range, limit of quantitation, and precision were determined from the comparative quantitation experiments. Importantly, the permanently charged HMEP mass tag not only increased the ionization efficiency of the studied fatty acids but also ensured that the solution phase properties of the analytes became more similar, allowing the use of CHCA as a single MALDI matrix compound for the entire range of analytes. The label exhibited a further very unique feature; it provided complete suppression of MALDI matrix-related ions. The MALDI assay was able to generate the data much faster than conventional gas chromatography (GC) methods for fatty acids. It is shown in this study that analyzing a single sample took less than 10 s with analytical results of comparable quality to those obtained by GC.
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Affiliation(s)
- Albert Koulman
- Medical Research Council, Elsie Widdowson Laboratory, Cambridge, United Kingdom
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24
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Persike M, Karas M. Rapid simultaneous quantitative determination of different small pharmaceutical drugs using a conventional matrix-assisted laser desorption/ionization time-of-flight mass spectrometry system. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2009; 23:3555-3562. [PMID: 19844965 DOI: 10.1002/rcm.4283] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The present study establishes a simple, rapid and sensitive method for the simultaneous quantification of different small pharmaceutical drugs using a matrix-assisted laser desorption/ionization source (MALDI) coupled with a time-of-flight (TOF) mass analyzer. Neither time-consuming sample preparation, nor special target plates, isotopically labelled internal standards or other extra equipment are necessary. A simple standard dried-droplet preparation with the common matrix alpha-cyano-4-hydroxycinnamic acid (CHCA) was used. The background signals of CHCA in the low-mass region did not pose the presumed problem, because the sensitivity, resolution and mass accuracy of a modern MALDI-TOF MS system is sufficient to overcome this difficulty. Four experiments were performed in order to verify the quantification method. First, ten different phenothiazines were quantified in the range of 5-2000 nM (1-880 ng/mL). A good precision (relative standard deviation (RSD) 4.4-9.3%), linearity (R2 >0.99) and accuracy (error 4.7-11%) was obtained in all cases. Additionally, simultaneous quantification of these ten phenothiazines was carried out in human plasma without prior chromatographic separation in the range of 2-1750 ng/mL yielding good linearity, precision and accuracy (mean RSD 7.6%; R2 >0.99, mean error 8.0%). Accordingly, a quantitative analysis of ten chemically and pharmaceutically unrelated drugs was performed in the same way. A comparable linearity (R2 >0.99), precision (mean RSD 7.6%) and accuracy (mean error 8.3%) was obtained in the range of 5-2000 nM. Finally, the prazosin content of a commercial tablet was directly determined without further purification steps.
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Affiliation(s)
- Markus Persike
- Cluster of Excellence Macromolecular Complexes, Institute of Pharmaceutical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany.
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25
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Höfner G, Merkel D, Wanner KT. MS Binding Assays-with MALDI toward High Throughput. ChemMedChem 2009; 4:1523-8. [DOI: 10.1002/cmdc.200900201] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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26
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Vilariño N, Fonfría ES, Molgó J, Aráoz R, Botana LM. Detection of gymnodimine-A and 13-desmethyl C spirolide phycotoxins by fluorescence polarization. Anal Chem 2009; 81:2708-14. [PMID: 19278248 DOI: 10.1021/ac900144r] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The gymnodimines and spirolides are phycotoxins classified into a heterogeneous group of marine biocompounds called cyclic imines. Although there is no clear evidence of their toxicity to humans, gymnodimines and spirolides are highly toxic to rodents and constitute a source of false positives in lipophilic toxin detection by the mouse bioassay. Using nicotinic acetylcholine receptor-enriched membranes of Torpedo, and fluorescent alpha-bungarotoxin, we developed a fluorescence polarization assay to detect and quantify gymnodimine-A and 13-desmethyl C spirolide. The presence of these cyclic imines in solution inhibited the interaction of fluorescent-labeled alpha-bungarotoxin with nicotinic acetylcholine receptors in a concentration-dependent manner. The sensitivity of the assay is in the order of nanomolar concentrations of gymnodimine and 13-desmethyl C spirolide. Okadaic acid, yessotoxin, and brevetoxin-2, three lipophilic marine toxins, did not interfere with this assay. A suitable extraction method in shellfish was also developed. The gymnodimine-A and 13-desmethyl C spirolide recovery rates of mussel matrix extraction with acetone/chloroform were 63.6% +/- 3.5% and 87.4% +/- 5.3%, respectively. In summary, this inhibition assay is capable of gymnodimine-A and 13-desmethyl C spirolide detection in mussel extracts with enough sensitivity and specificity to quantify these toxins in the range of 50-2000 microg/kg and 70-700 microg/kg of shellfish meat, respectively.
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Affiliation(s)
- Natalia Vilariño
- Departamento de Farmacología, Facultad de Veterinaria, Campus Universitario, Universidad de Santiago de Compostela, 27002 Lugo, Spain
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27
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van Kampen JJA, Burgers PC, Gruters RA, Osterhaus ADME, de Groot R, Luider TM, Volmer DA. Quantitative analysis of antiretroviral drugs in lysates of peripheral blood mononuclear cells using MALDI-triple quadrupole mass spectrometry. Anal Chem 2008; 80:4969-75. [PMID: 18533679 DOI: 10.1021/ac800218a] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report here on the use of a prototype matrix-assisted laser desorption/ionization (MALDI)-triple quadrupole mass spectrometer for quantitative analysis of six antiretroviral drugs in lysates of peripheral blood mononuclear cells (PBMC). Of the five investigated MALDI matrixes, 2,5-dihydroxybenzoic acid (DHB) and the novel 7-hydroxy-4-(trifluoromethyl)coumarin (HFMC) showed the broadest application ranges for the antiretroviral drugs. For DHB, the mean relative errors ranged from 8.3 (ritonavir) to 4.3% (saquinavir). The mean precisions (CV) ranged from 17.3 (nevirapine) to 10.8% (saquinavir). The obtained lower limits of quantitation (LLOQ) readily allow clinical applications using just 1 million PBMC from HIV-infected patients under therapy. The new matrix HFMC was used for quantitative analysis of the HIV protease inhibitor indinavir using a stainless steel target plate as well as a target plate with a novel, strongly hydrophobic fluoropolymer coating. Using the coated target plate, the mean relative error improved from 10.1 to 4.6%, the mean precision from 33.9 to 9.9% CV, and the LLOQ from 16 to 1 fmol. In addition, the measurement time for one spot went down from 6 to only 2.5 s.
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Affiliation(s)
- Jeroen J A van Kampen
- Department of Neurology, Laboratory of Neuro-Oncology and Clinical & Cancer Proteomics, Erasmus MC, Rotterdam, The Netherlands
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28
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van Kampen JJA, Burgers PC, de Groot R, Osterhaus ADME, Reedijk ML, Verschuren EJ, Gruters RA, Luider TM. Quantitative Analysis of HIV-1 Protease Inhibitors in Cell Lysates Using MALDI-FTICR Mass Spectrometry. Anal Chem 2008; 80:3751-6. [DOI: 10.1021/ac702072c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jeroen J. A. van Kampen
- Department of Neurology, Laboratory of Neuro-Oncology and Clinical and Cancer Proteomics and Department of Virology, Erasmus MC, Rotterdam, The Netherlands, Department of Pediatrics, Division of Pediatric Infectious Diseases & Immunology, Erasmus MC-Sophia, Rotterdam, The Netherlands, and Department of Pediatrics, UMC St. Radboud, Nijmegen, The Netherlands
| | - Peter C. Burgers
- Department of Neurology, Laboratory of Neuro-Oncology and Clinical and Cancer Proteomics and Department of Virology, Erasmus MC, Rotterdam, The Netherlands, Department of Pediatrics, Division of Pediatric Infectious Diseases & Immunology, Erasmus MC-Sophia, Rotterdam, The Netherlands, and Department of Pediatrics, UMC St. Radboud, Nijmegen, The Netherlands
| | - Ronald de Groot
- Department of Neurology, Laboratory of Neuro-Oncology and Clinical and Cancer Proteomics and Department of Virology, Erasmus MC, Rotterdam, The Netherlands, Department of Pediatrics, Division of Pediatric Infectious Diseases & Immunology, Erasmus MC-Sophia, Rotterdam, The Netherlands, and Department of Pediatrics, UMC St. Radboud, Nijmegen, The Netherlands
| | - Albert D. M. E. Osterhaus
- Department of Neurology, Laboratory of Neuro-Oncology and Clinical and Cancer Proteomics and Department of Virology, Erasmus MC, Rotterdam, The Netherlands, Department of Pediatrics, Division of Pediatric Infectious Diseases & Immunology, Erasmus MC-Sophia, Rotterdam, The Netherlands, and Department of Pediatrics, UMC St. Radboud, Nijmegen, The Netherlands
| | - Mariska L. Reedijk
- Department of Neurology, Laboratory of Neuro-Oncology and Clinical and Cancer Proteomics and Department of Virology, Erasmus MC, Rotterdam, The Netherlands, Department of Pediatrics, Division of Pediatric Infectious Diseases & Immunology, Erasmus MC-Sophia, Rotterdam, The Netherlands, and Department of Pediatrics, UMC St. Radboud, Nijmegen, The Netherlands
| | - Esther J. Verschuren
- Department of Neurology, Laboratory of Neuro-Oncology and Clinical and Cancer Proteomics and Department of Virology, Erasmus MC, Rotterdam, The Netherlands, Department of Pediatrics, Division of Pediatric Infectious Diseases & Immunology, Erasmus MC-Sophia, Rotterdam, The Netherlands, and Department of Pediatrics, UMC St. Radboud, Nijmegen, The Netherlands
| | - Rob A. Gruters
- Department of Neurology, Laboratory of Neuro-Oncology and Clinical and Cancer Proteomics and Department of Virology, Erasmus MC, Rotterdam, The Netherlands, Department of Pediatrics, Division of Pediatric Infectious Diseases & Immunology, Erasmus MC-Sophia, Rotterdam, The Netherlands, and Department of Pediatrics, UMC St. Radboud, Nijmegen, The Netherlands
| | - Theo M. Luider
- Department of Neurology, Laboratory of Neuro-Oncology and Clinical and Cancer Proteomics and Department of Virology, Erasmus MC, Rotterdam, The Netherlands, Department of Pediatrics, Division of Pediatric Infectious Diseases & Immunology, Erasmus MC-Sophia, Rotterdam, The Netherlands, and Department of Pediatrics, UMC St. Radboud, Nijmegen, The Netherlands
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29
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Lawton LA, Edwards C. Conventional laboratory methods for cyanotoxins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 619:513-37. [DOI: 10.1007/978-0-387-75865-7_23] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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30
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Scherl A, Shaffer SA, Taylor GK, Kulasekara HD, Miller SI, Goodlett DR. Genome-specific gas-phase fractionation strategy for improved shotgun proteomic profiling of proteotypic peptides. Anal Chem 2008; 80:1182-91. [PMID: 18211032 DOI: 10.1021/ac701680f] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Gas-phase fractionation (GPF) is an efficient and straightforward method to increase proteome coverage. In this report, optimal m/z ranges were calculated based on genomic complexity and experimental data. Then, theoretical precursor ion densities were calculated in silico from various organisms' genomes and found to corroborate the empirical selection of m/z ranges based on ion density mapping. According to both calculations, the choice of m/z range for most efficient GPF coverage in the lower m/z range should be very narrow and increase as m/z value increases. Next, a systematic LC-MS/MS analysis was performed to confirm this observation. The behavior of data-dependent precursor ion selection and the origin of the observed variability was investigated under three different scan modes of an LTQ-Orbitrap hybrid mass spectrometer. Finally, GPF combined with data-dependent analysis was compared to a targeted, pseudo-multiple reaction monitoring analysis of proteotypic peptides that should be, based on empirical observation of LC-ESI-MS/MS data, detectable. The result of the latter experiment supported our conclusion that data-dependent analysis using rational gas-phase fractionation was sufficient for comprehensive proteomic analysis of the proteotypic peptides in an unfractionated cell lysate.
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Affiliation(s)
- Alexander Scherl
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA
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31
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Volmer DA, Sleno L, Bateman K, Sturino C, Oballa R, Mauriala T, Corr J. Comparison of MALDI to ESI on a Triple Quadrupole Platform for Pharmacokinetic Analyses. Anal Chem 2007; 79:9000-6. [DOI: 10.1021/ac7016234] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Dietrich A. Volmer
- Medical Research Council, Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, United Kingdom, Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Ontario, Canada, Merck Frosst Centre for Therapeutic Research, Kirkland, Quebec, Canada, and MDS Analytical Technologies, Concord, Ontario, Canada
| | - Lekha Sleno
- Medical Research Council, Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, United Kingdom, Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Ontario, Canada, Merck Frosst Centre for Therapeutic Research, Kirkland, Quebec, Canada, and MDS Analytical Technologies, Concord, Ontario, Canada
| | - Kevin Bateman
- Medical Research Council, Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, United Kingdom, Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Ontario, Canada, Merck Frosst Centre for Therapeutic Research, Kirkland, Quebec, Canada, and MDS Analytical Technologies, Concord, Ontario, Canada
| | - Claudio Sturino
- Medical Research Council, Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, United Kingdom, Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Ontario, Canada, Merck Frosst Centre for Therapeutic Research, Kirkland, Quebec, Canada, and MDS Analytical Technologies, Concord, Ontario, Canada
| | - Renata Oballa
- Medical Research Council, Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, United Kingdom, Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Ontario, Canada, Merck Frosst Centre for Therapeutic Research, Kirkland, Quebec, Canada, and MDS Analytical Technologies, Concord, Ontario, Canada
| | - Timo Mauriala
- Medical Research Council, Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, United Kingdom, Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Ontario, Canada, Merck Frosst Centre for Therapeutic Research, Kirkland, Quebec, Canada, and MDS Analytical Technologies, Concord, Ontario, Canada
| | - Jay Corr
- Medical Research Council, Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, United Kingdom, Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Ontario, Canada, Merck Frosst Centre for Therapeutic Research, Kirkland, Quebec, Canada, and MDS Analytical Technologies, Concord, Ontario, Canada
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32
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Maki T, Ishida K. Photocleavable Molecule for Laser Desorption Ionization Mass Spectrometry. J Org Chem 2007; 72:6427-33. [PMID: 17636957 DOI: 10.1021/jo070621b] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new photocleavable molecule for laser desorption ionization mass spectrometry (LDI-MS) was designed and synthesized. The molecule exhibited high sensitivity for negative mode MS detection with good chemical stability. The molecule was successfully applied to molecular tag for (LDI-MS). Kinetic measurement of the amidation reaction and monitoring of aminolysis of acetylated sugars were demonstrated with the molecular tag.
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Affiliation(s)
- Toshihide Maki
- Joint Research Center, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
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33
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Gogichaeva NV, Williams T, Alterman MA. MALDI TOF/TOF tandem mass spectrometry as a new tool for amino acid analysis. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2007; 18:279-84. [PMID: 17074506 DOI: 10.1016/j.jasms.2006.09.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 09/18/2006] [Accepted: 09/20/2006] [Indexed: 05/12/2023]
Abstract
This is the first report of an application of collisionally induced fragmentation of amino acids (AA) and their derivatives by MALDI TOF/TOF tandem mass spectrometry (MS). In this work, we collected the data on high-energy fragmentation reactions of a large group of protonated amino acids and their derivatives with the goal of determining which product ions are analyte specific and if yields of these fragment could be used for quantitative analysis. From 34 different amino acids (20 alpha-amino acids, beta-amino acids, homocysteine, GABA, and modified AA Met sulfone and sulfoxide, hydroxyproline, etc.) we observed that high yields of the target specific immonium ions and fragmentation patterns are most similar to EI or FAB CID on sector instruments. The major exceptions were two highly basic amino acids, Arg and Orn. It is noted that neither beta-, gamma-, nor delta-amino acids produce immonium ions. As might be predicted from high-energy CID work on peptides from the sectors and TOF/TOF, the presence of specific indicator ions in MALDI tandem MS allows distinguishing isomeric and isobaric amino acids. These indicator ions, in combination with careful control of data acquisition, ensure quantitative analysis of amino acids. We believe our data provide strong basis for the application of MALDI TOF/TOF MS/MS in qualitative and quantitative analysis of amino and organic acids, including application in clinical medicine.
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Kovarik P, Grivet C, Bourgogne E, Hopfgartner G. Method development aspects for the quantitation of pharmaceutical compounds in human plasma with a matrix-assisted laser desorption/ionization source in the multiple reaction monitoring mode. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2007; 21:911-9. [PMID: 17295425 DOI: 10.1002/rcm.2912] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The present work investigates various method development aspects for the quantitative analysis of pharmaceutical compounds in human plasma using matrix-assisted laser desorption/ionization and multiple reaction monitoring (MALDI-MRM). Talinolol was selected as a model analyte. Liquid-liquid extraction (LLE) and protein precipitation were evaluated regarding sensitivity and throughput for the MALDI-MRM technique and its applicability without and with chromatographic separation. Compared to classical electrospray liquid chromatography/mass spectrometry (LC/ESI-MS) method development, with MALDI-MRM the tuning of the analyte in single MS mode is more challenging due to interfering matrix background ions. An approach is proposed using background subtraction. With LLE and using a 200 microL human plasma aliquot acceptable precision and accuracy could be obtained in the range of 1 to 1000 ng/mL without any LC separation. Approximately 3 s were required for one analysis. A full calibration curve and its quality control samples (20 samples) can be analyzed within 1 min. Combining LC with the MALDI analysis allowed improving the linearity down to 50 pg/mL, while reducing the throughput potential only by two-fold. Matrix effects are still a significant issue with MALDI but can be monitored in a similar way to that used for LC/ESI-MS analysis.
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van Kampen JJA, Verschuren EJ, Burgers PC, Luider TM, de Groot R, Osterhaus ADME, Gruters RA. Validation of an HIV-1 inactivation protocol that is compatible with intracellular drug analysis by mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2006; 847:38-44. [PMID: 17055786 DOI: 10.1016/j.jchromb.2006.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 09/27/2006] [Accepted: 10/01/2006] [Indexed: 11/28/2022]
Abstract
Mass spectrometry is a powerful tool for studying the intracellular pharmacokinetics of antiretroviral drugs. However, the biohazard of HIV-1 calls for a safety protocol for such analyses. To this end, we extracted HIV-1 producing cells with methanol or ethanol at 4 degrees C. After extraction, no viral infectivity was detected, as shown by a reduction in infectious titers of more than 6log. In addition, this protocol is compatible with the quantitative analysis of antiretroviral drugs in cell extracts using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS. Thus, using this protocol, infectious HIV-1 is inactivated and antiretroviral drugs are extracted from cells in a single step.
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Affiliation(s)
- Jeroen J A van Kampen
- Department of Neurology, Laboratory of Neuro-Oncology, Erasmus MC, Rotterdam, The Netherlands
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Tholey A, Heinzle E. Ionic (liquid) matrices for matrix-assisted laser desorption/ionization mass spectrometry-applications and perspectives. Anal Bioanal Chem 2006; 386:24-37. [PMID: 16830111 DOI: 10.1007/s00216-006-0600-5] [Citation(s) in RCA: 233] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Revised: 06/06/2006] [Accepted: 06/07/2006] [Indexed: 11/30/2022]
Abstract
A large number of matrix substances have been used for various applications in matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). The majority of matrices applied in ultraviolet-MALDI MS are crystalline, low molecular weight compounds. A problem encountered with many of these matrices is the formation of hot spots, which lead to inhomogeneous samples, thus leading to increased measurement times and hampering the application of MALDI MS for quantitative purposes. Recently, ionic (liquid) matrices (ILM or IM) have been introduced as a potential alternative to the classical crystalline matrices. ILM are equimolar mixtures of conventional MALDI matrix compounds such as 2,5-dihydroxybenzoic acid (DHB), alpha-cyano-4-hydroxycinnamic acid (CCA) or sinapinic acid (SA) together with organic bases [e.g., pyridine (Py), tributylamine (TBA) or N,N-dimethylethylenediamine (DMED)]. The present article presents a first overview of this new class of matrices. Characteristic properties of ILM, their influence on mass spectrometric parameters such as sensitivity, resolution and adduct formation and their application in the fields of proteome analysis, the measurement of low molecular weight compounds, the use of MALDI MS for quantitative purposes and in MALDI imaging will be presented. Scopes and limitations for the application of ILM are discussed.
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Affiliation(s)
- Andreas Tholey
- Technische Biochemie, Geb. 1.5, Universität des Saarlandes, 66123 Saarbrücken, Germany.
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van Kampen JJA, Burgers PC, de Groot R, Luider TM. Qualitative and Quantitative Analysis of Pharmaceutical Compounds by MALDI-TOF Mass Spectrometry. Anal Chem 2006; 78:5403-11. [PMID: 16878875 DOI: 10.1021/ac060436i] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this report, we discuss key issues for the successful application of MALDI-TOF mass spectrometry to quantify drugs. These include choice and preparation of matrix, nature of cationization agent, automation, and data analysis procedures. The high molecular weight matrix meso-tetrakis(pentafluorophenyl)porphyrin eliminates chemical noise in the low-mass range, a "brushing" spotting technique in combination with prestructured target plates enables fast preparation of homogeneous matrix crystals, and addition of Li+ leads to intense cationized drug species. Complex biological samples were cleaned up using a 96-well solid-phase extraction plate, and the purified samples were automatically spotted by a pipetting robot. To obtain a suitable data analysis procedure for the quantitative analysis of drugs by MALDI-TOF mass spectrometry, various data processing parameters were evaluated on our two model drugs lopinavir and ritonavir. Finally, and most importantly, it is shown that the above-described procedure can be successfully applied to quantify clinically relevant concentrations of lopinavir, an HIV protease inhibitor, in extracts of small numbers of peripheral blood mononuclear cells (1 x 10(6)).
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Affiliation(s)
- Jeroen J A van Kampen
- Department of Neurology, Laboratory of Neuro-Oncology, and Department of Pediatrics, Division of Pediatric Infectious Diseases & Immunology, Sophia Children's Hospital, Erasmus Medical Center, Rotterdam, The Netherlands
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Hatakeyama T, Chen DL, Ismagilov RF. Microgram-scale testing of reaction conditions in solution using nanoliter plugs in microfluidics with detection by MALDI-MS. J Am Chem Soc 2006; 128:2518-9. [PMID: 16492019 PMCID: PMC1851926 DOI: 10.1021/ja057720w] [Citation(s) in RCA: 162] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper describes a microfluidic system to screen and optimize organic reaction conditions on a submicrogram scale. The system uses discrete droplets (plugs) as microreactors separated and transported by a continuous phase of a fluorinated carrier fluid. Previously, we demonstrated the use of a microfabricated PDMS plug-based microfluidic system to perform assays and crystallization experiments in aqueous solutions with optical detection. Here, we developed an approach that does not require microfabrication of microfluidic devices, is applicable to synthetic reactions in organic solvents, and uses detection by MALDI-MS. As a demonstration, conditions for selective deacetylation of ouabain hexaacetate were tested, and the optimum conditions for mono-, bis-, or trisdeacetylation have been identified. These conditions were validated by scale-up reactions and isolating these potentially neurotoxic products. Mono- and bisdeacetylated products are unstable intermediates in the deacetylation and were isolated for the first time. This system enables no-loss handling of submicroliter volumes containing a few micrograms of a compound of interest. It could become valuable for investigating or optimizing reactions of precious substrates (e.g., products of long synthetic sequences and natural products that can be isolated only in small quantities).
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Sleno L, Volmer DA. Assessing the properties of internal standards for quantitative matrix-assisted laser desorption/ionization mass spectrometry of small molecules. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2006; 20:1517-24. [PMID: 16628567 DOI: 10.1002/rcm.2498] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Growing interest in the ability to conduct quantitative assays for small molecules by matrix-assisted laser desorption/ionization (MALDI) has been the driving force for several recent studies. This present work includes the investigation of internal standards for these analyses using a high-repetition rate MALDI triple quadrupole instrument. Certain physicochemical properties are assessed for predicting possible matches for internal standards for different small molecules. The importance of similar molecular weight of an internal standard to its analyte is seen through experiments with a series of acylcarnitines, having a fixed charge site and growing alkyl chain length. Both acetyl- and hexanoyl-carnitine were systematically assessed with several other acylcarnitine compounds as internal standards. The results clearly demonstrate that closely matched molecular weights between analyte and internal standard are essential for acceptable quantitation results. Using alpha-cyano-4-hydroxycinnamic acid as the organic matrix, the similarities between analyte and internal standard remain the most important parameter and not necessarily their even distribution within the solid sample spot. Several 4-quinolone antibiotics as well as a diverse group of pharmaceutical drugs were tested as internal standards for the 4-quinolone, ciprofloxacin. Quantitative results were shown using the solution-phase properties, log D and pKa, of these molecules. Their distribution coefficients, log D, are demonstrated as a fundamental parameter for similar crystallization patterns of analyte and internal standard. In the end, it was also possible to quantify ciprofloxacin using a drug from a different compound class, namely quinidine, having a similar log D value as the analyte.
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Affiliation(s)
- Lekha Sleno
- Institute for Marine Biosciences, 1411 Oxford Street, Halifax, Nova Scotia, Canada B3H 3Z1
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Tholey A, Zabet-Moghaddam M, Heinzle E. Quantification of Peptides for the Monitoring of Protease-Catalyzed Reactions by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Using Ionic Liquid Matrixes. Anal Chem 2006; 78:291-7. [PMID: 16383339 DOI: 10.1021/ac0514319] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ionic liquid matrixes (ILM) have been shown to allow very homogeneous sample preparations, facilitating relative quantifications using internal standards in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). In the present work, the ability to perform quantifications of peptides without using internal standards in these matrixes was investigated. Linear correlations between peptide amount and signal intensities could be observed when increased molar matrix-to-analyte ratios were applied. The dynamic range of linearity was approximately 1 order of magnitude. The method was applied successfully to monitor the time-dependent evolution of substrates and products in trypsin-catalyzed digests of single peptides and peptide mixtures. Thus, ionic liquid matrixes allow quantitative MALDI-MS without the need for internal standards, making the method a suitable tool for the fast screening of new enzymes or the search for substrates or inhibitors.
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Affiliation(s)
- Andreas Tholey
- Technische Biochemie, Universität des Saarlandes, 66123 Saarbrücken, Germany.
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Melanson JE, Chisholm KA, Pinto DM. Targeted comparative proteomics by liquid chromatography/matrix-assisted laser desorption/ionization triple-quadrupole mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2006; 20:904-10. [PMID: 16470697 DOI: 10.1002/rcm.2391] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Here we report the first application of a matrix-assisted laser desorption/ionization (MALDI) triple-quadrupole mass spectrometer for targeted proteomics. Employing an amine-specific isotopic labelling approach, the technique was validated using five randomly selected bovine serum albumin peptides differentially labelled at known ratios. An indirect benefit of the isotopic labelling technique is a significant enhancement of the a1 ion in tandem mass (MS/MS) spectra of all peptides studied. Therefore, the a1 ion was selected as the fragment ion for multiple reaction monitoring (MRM) in all cases, eliminating tedious method development and optimization. Accurate quantification was achieved with an average relative standard deviation (RSD) of 5% (n = 5) and a detection limit of 14 amol. The technique was then applied to validate an important virulence biomarker of the fungal pathogen Candida albicans, which was not accurately quantified using global proteomics experiment employing two-dimensional liquid chromatography/electrospray ionization tandem mass spectrometry (2D-LC/ESI)-MS/MS. Using LC/MALDI-MRM analysis of five tryptic peptides, the protein PHR1 was found to be upregulated in the hyphal (pathogenic) form of C. albicans by a factor of 7.7 +/- 0.8.
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Affiliation(s)
- Jeremy E Melanson
- Institute for Marine Biosciences, National Research Council of Canada, 1411 Oxford St., Halifax, Nova Scotia, Canada B3H 3Z1
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Sleno L, Volmer DA. Some fundamental and technical aspects of the quantitative analysis of pharmaceutical drugs by matrix-assisted laser desorption/ionization mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2005; 19:1928-36. [PMID: 15954169 DOI: 10.1002/rcm.2006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The purpose of the present paper was to study some of the underlying physical and technical aspects of high-throughput quantitative matrix-assisted laser desorption/ionization (MALDI) of small drug molecules. A prototype MALDI-triple quadrupole instrument equipped with a high repetition rate laser was employed. Initially, the detection limits and dynamic ranges for the quantitation of four drugs (quinidine, danofloxacin, ramipril and nadolol) were determined. Internal standards were carefully chosen for each of these analytes in terms of structure similarity and fragmentation pathways. Three organic matrices were tested for these assays, resulting in different crystallization behaviors and measurement reproducibilities. alpha-Cyano-4-hydroxycinnamic acid yielded the best results and was subsequently employed for the quantitative determination of all four analytes. Further experiments considered the role of laser energy and pulse rate on the ablated areas as well as ion signals. Light microscope and scanning electron microscope images allowed the examination of the ablated area of the MALDI spots. The images showed convincing evidence that the ablated area was virtually void of crystals after analysis, with no preferential removal of material in the center of the laser's path. Average values for the amount of material ablated were determined to be 3.9+/-0.5% of the total spot size, and as low as 19.5 attomoles of analyte were detectable for our most sensitive analyte, ramipril. It was calculated that, under these assay conditions, it was possible to accurately quantify less than 1 femtomole of all analytes with the use of appropriately pure internal standards. These studies showed very promising results for the quantitative nature of MALDI for small molecules with molecular weights less than 500 Da.
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Affiliation(s)
- Lekha Sleno
- Institute for Marine Biosciences, National Research Council, 1411 Oxford St., Halifax, NS, Canada B3H 3Z1
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