Publication Abstract

Receptor binding protein amperometric affinity sensor for rapid β-lactum quantification in milk

S.J. Setford, R.M. Van Es, Y.J. Blankwater and S. Kroger

Screen-printed devices, incorporating working electrode immobilised β-lactam specific receptor binding protein, were employed to measure penicillin G levels in milk. Quantification was achieved through ELISA-based affinity-assay format coupled to amperometric determination of bound enzyme label activity. Assay inhibition increased from zero, in the absence of penicillin G in milk, to 33.5 and 77.1% reduction in signal response in the presence of 5 µg kg^-1 and 10 µg kg^-1 penicillin G, respectively. The maximum residue limit of penicillin G in milk for consumption is 5 µkg^-1, as defined by the FDA. Coefficient of variation values varied from 4.2-26.4%. The assay incorporates a 2-4 min incubation step, a rapid washing step and 1-2 min measurement step. The receptor binding protein is specific for the major β-lactam antibiotic types. The assay is simple to perform and requires minimum reagent usage, making it ideal as a field-based screening tool for β-lactam quantification in milk.

Reference:

S.J. Setford, R.M. Van Es, Y.J. Blankwater and S. Kroger, 1999. Receptor binding protein amperometric affinity sensor for rapid b-lactum quantification in milk. Analytica Chibica Acta, 398: 13-22.