A novel amperometric biosensor for detection of penicillin in milk

A novel disposable screen-printed biosensor for low level detection of penicillin in milk is reported. Penicillin binding protein (PBP) is used for immobilisation of both penicillin and the enzyme conjugate, i.e. beta-lactum analogue labelled with the enzyme glucose oxidase (7ACA-GOD) on the working electrode of a screen-printed sensor. The residual glucose oxidase on the electrode is used to catalyse glucose to produce hydrogen peroxide. The amount of GOD immobilised on the surface of the PBP electrode and hence the current is inversely proportional to the penicillin concentration.