Ethyl Chloroformate as Derivatizing Reagent for Gas Chromatographic Determination of α-Keto acids and Amino acids from Pharmaceutical Preparation

Abstract

α-keto acids pyruvic acid (PYR), 2-ketobutyric acid (KBA), 3-methyl-2-oxobutyric acid (MKBA), 3- methyl-2-oxovalaric acid M3KVA), 4- methyl-2-oxovalaric acid (M4KVA), 2- ketohexanoic acid (KHA) and phenylpyruvic acid (PPYR) together with amino acids as derivatives of ethyl chloroformate (ECF) eluted and separated from GC column HP-5(30m x 0.32 mm id). The detection was by flame ionization ( (FID). Linear calibration curves were obtained within 18-127.8 µg/mL and detection limits were within 6-8.6 µg/mL of each α-keto acid. The separation was repeatable with inter and intraday variation with relative standard deviation (RSD) within 0.2-3.5%. A pharmaceutical preparation Ketosteril was analyzed and amounts of MKBA, M3KVA, M4KVA, and PPYR correlated with labeled values and their amount extracted from pharmaceutical preparation by standard addition were calculated to 93.92 -96.1 % with RSD 0.3-0.7%. The amino acids present in Ketosteril tablet separated completely and were determined simultaneously together with α-keto acids with recovery of 95.8 to 98.65% with RSD 0.2-0.9%.