Electrochemical determination of lipoic acid

Abstract

Procedures for determining lipoic acid by voltammetry and coulometric titration with electrogenerated halogens using the biamperometric indication of the titration end-point were developed. Possible mechanisms of lipoic acid oxidation with electrogenerated halogens are discussed. Microgram amounts of lipoic acid were determined in model solutions with an RSD of 1-2%. The analytical range of lipoic acid found by voltammetry at a glassy-carbon electrode lies between 1.15 × 10-5 and 1.73 × 10 -4 M. The detection limit for lipoic acid is 5.75 × 10 -6 M.