Biosensor for the enantioselective analysis of the thyroid hormones (+)-3,3′,5-triiodo-L-thyronine (T3) and (+)-3,3′,5,5′-tetraiodo-L-thyronine (T4)

An amperometric biosensor based on L-aminoacid oxidase is proposed for enantioselective assay of (+)-3,3',5-triiodol-thyronine (L-T-3) and (+)-3,3',5,5'-tetraiodo-L-thyronine (L-T-4), due to the fact that only the L enantiomer has the hormonal activity. The construction of the amperometric biosensor is simple and reproducible. The analytical information obtained from enantioselective analysis are reliable. The RSD <1% assured by using the amperometric biosensors for L enantiomers assay as raw materials, and from tablets, demonstrated their suitability for the analysis of T-3 and T-4 at ppb concentration levels.