Biosensor for the enantioselective analysis of S-captopril

An amperometric biosensor, based on l-aminoacid oxidase is proposed for S-captopril assay. The working range of biosensor is between 2 and 100 μmol/l, with a limit of detection of 1 μmol/l. Enantioselectivity versus R-enantiomer is demonstrated by the amperometric selectivity coefficient (1.1×10−3 and 0, when the concentration of R-captopril solution is 10 and 150 μmol/l, respectively). The working pH range is between 6 and 7.2. The amperometric biosensor can be used for enantioselective assay of S-captopril as raw material, and from tablets without any prior separation of the active compound, with a R.S.D. less than 1%. Its lifetime is 3 weeks.