Quantification of free amino acids and dipeptides using isotope dilution liquid chromatography and electrospray ionization tandem mass spectrometry
Our aim was to develop a liquid chromatography and electrospray ionization tandem mass spectrometry (LCMS²) method to measure free amino acid (FAA) and dipeptide (DP) concentrations in biological fluids. We synthesized chloroformate derivatives of FAA and DP, identified the major precursor ions and...
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Published in | Amino acids Vol. 32; no. 2; pp. 203 - 212 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Austria
Vienna : Springer-Verlag
01.02.2007
Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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Summary: | Our aim was to develop a liquid chromatography and electrospray ionization tandem mass spectrometry (LCMS²) method to measure free amino acid (FAA) and dipeptide (DP) concentrations in biological fluids. We synthesized chloroformate derivatives of FAA and DP, identified the major precursor ions and used LCMS² to obtain the most intense product ions. Using serial dilutions of unlabeled and labeled standards ([²H₃]-L-Dopa, homoarginine, homophenylalanine, [¹⁵N]-Glutamine and [²H₃]-methionine), we observed linear relationships in MS response that we used to calculate the amounts of FAA and DP in biological samples. This method is sensitive with a limit of detection (LOD) for most of the FAAs and DPs tested in the 0.05-1 pmol range and is linear over 3-5 orders of magnitude when many metabolites were measured simultaneously. Reproducibility and between run or daily variations were <10% for most FAAs and DPs. We applied this method to human samples and quantitatively measured 21 FAAs and 2 DPs in 200 μl CSF, 31 FAAs and 6 DPs in 100 μl plasma, and 23 FAAs and 5 DPs in 200 μl urine. These data demonstrate the potential for using LCMS² to discover changes in FAA and DP metabolic pathways that occur during disease pathogenesis. |
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Bibliography: | http://dx.doi.org/10.1007/s00726-006-0370-6 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0939-4451 1438-2199 |
DOI: | 10.1007/s00726-006-0370-6 |