Abstract
Gas chromatographic seperation by direct injection of a mixture of dihydrolipoic acid, lipoic acid, and lipoamide was examined using the column packing of 15% diethyleneglycol succinate polyester on Chromosorb W at 220 to 230℃ with carrier gas of nitrogen and the flame ionization detector. Calibration curves for the determination were obtained using di-n-octyl phthalate for lipoic acid and benzyl n-butyl phthalate for lipoamide as the internal standard, respectively. Lipoic acid and lipoamide in the pharmaceuticals were readily determined from the chloroform extracts with mean recovery±standard deviation of 98.9±2.9% and 98.8±2.7%, respectively. Procedures are presented in detail.
