Determination of amino acid enantiomers in human urine and blood serum by gas chromatography-mass spectrometry

Amino acid (AA) enantiomers were determined as N(O)-pentafluoropropionyl-(2 )-propyl esters by chiral gas chromatography-mass spectrometry (GC-MS) in 2 4 h samples of the urine of three healthy volunteers and in their blood ser a. In urine the largest amounts were determined for D-Ser (64-199 mu mol/da y) and D-Ala (24-138 mu mol/day). In blood sera, D-Ala (2.3-4.2 mu mol/ L) and D-Ser (1.0-2.9 mu mol/L) were most abundant. Varying amounts of the D-e nantiomers of Thr, Pro, Asx, Glx, Phe, Tyr, Om and Lys were also found, alb eit not in all urines and sera. Further, enantiomers were quantified in uri ne samples of two volunteers fasting for 115 h. Quantities of renally excre ted D-AAs decreased in fasting, although amounts of D-Ser (69 and 77 mu mol /L urine) as well as other D-AAs were still detectable. Time-dependent anal yses of urine showed that D-AAs are continuously excreted. Copyright (C) 20 01 John Wiley & Sons, Ltd.