DETERMINATION OF D,L-AMINO ACIDS IN NATURAL-WATER BY GAS-CHROMATOGRAPHY WITH ENANTIOMER LABELING

Amino acids in natural water have been determined quantitatively inform of L-isomers. At the same time their D/L ratios have been determined by gas chromatography with enantiomer labeling. The water was sampled at Biwako, Kinokawa and Takihata. For an analysis of free amino acids, a batch technique was used to preconcentrate the amino acids by ion-exchange resin of Dowex 50 W-X8. For total dissolved amino acids, the water sample was first heated in 6 M HCI to hydrolyze the bound amino acids, and then purified by a column packed with Dowex 50W-X8. The major amino acids in natural water samples were found to be Thr, Ser, Asp and Orn in free form, and Gly, Ser, Asp and Glu in total dissolved form. In addition, some amino acids in free form showed high D/L ratio that might be due to the pollution.