Amperometric Penicillin Biosensor and Its Application in Flow Injection Analysis System for Determination of Penicillin in Broth

Abstract

An amperometric biosensor for determination of penicillin was developed. Penicillinase was immobilized by cross-linking with glutaraldehyde and bovine serum albumin, which was dropped on a platinum disc electrode. The principle of this electrode is based on the classical iodometric penicillin assay. The required hydrolysis is performed by immobilized penicillinase. Enzymatic hydrolysis of the β-lactam ring results in the formation of the corresponding penicilloic acid, which consumes iodine. The excess of iodine is determined amperometrically. The electrode was used to perform more than 1000 assays in 2 weeks and successfully used to determine penicillin in broth. The linearity, pH, interferences, and buffer strength dependence of the electrode were examined and discussed.