Abstract
A tube assay method with Streptococcus faecalis R for the determination of total lipoic acid in urine was investigated. The urine samples were hydrolyzed by autoclaving for 1 hour with 6N HCl under nitrogen and in the presence of about 5mg per tube of bovine serum albumin. The hydrolyzed mixture was diluted, neutralized and the aliquots were allowed to the determination by the tube assay method. The recoveries of lipoic acid added to the urine were complete and the estimated values of lipoic acid were highest among other treated samples. Conjugated lipoic acid in urine were not hydrolyzed with some proteolytic enzymes or lipoamidases.
