caa a22 4500 463185889 CHVBK 20180406164852.0 cr unu---uuuuu 170326e20070201xx s 000 0 eng 10.1007/s00726-006-0370-6 doi (NATIONALLICENCE)springer-10.1007/s00726-006-0370-6 Quantification of free amino acids and dipeptides using isotope dilution liquid chromatography and electrospray ionization tandem mass spectrometry [Elektronische Daten] [A. N. Fonteh, R. J. Harrington, M. G. Harrington] 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. Springer-Verlag, 2006 Keywords: Amino acids - Dipeptides - Liquid chromatography - Tandem mass spectrometry - Cerebrospinal fluid - Plasma - Urine nationallicence LCMS2 : Liquid chromatography and electrospray ionization tandem mass spectrometry nationallicence SRM : selected reaction monitoring nationallicence FAA : free amino acid nationallicence DP : dipeptide nationallicence GABA : γ-aminobutyric acid nationallicence βABA : β-aminobutyric acid nationallicence ABA : α-aminobutyric acid nationallicence DABA : 2,4-diaminobutyric acid nationallicence Dopa : 3,4-dihydroxyphenyl-L-alanine nationallicence Fonteh A. N. Molecular Neurology Program, Huntington Medical Research Institutes, Pasadena, CA, U.S.A. aut Harrington R. J. Molecular Neurology Program, Huntington Medical Research Institutes, Pasadena, CA, U.S.A. aut Harrington M. G. Molecular Neurology Program, Huntington Medical Research Institutes, Pasadena, CA, U.S.A. aut Amino Acids Springer-Verlag 32/2(2007-02-01), 203-212 0939-4451 32:2<203 2007 32 726 https://doi.org/10.1007/s00726-006-0370-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00726-006-0370-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Fonteh A. N. Molecular Neurology Program, Huntington Medical Research Institutes, Pasadena, CA, U.S.A aut NATIONALLICENCE 700 1- Harrington R. J. Molecular Neurology Program, Huntington Medical Research Institutes, Pasadena, CA, U.S.A aut NATIONALLICENCE 700 1- Harrington M. G. Molecular Neurology Program, Huntington Medical Research Institutes, Pasadena, CA, U.S.A aut NATIONALLICENCE 773 0- Amino Acids Springer-Verlag 32/2(2007-02-01), 203-212 0939-4451 32:2<203 2007 32 726 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer