Studies on residual antibacterials in foods : IV. Simultaneous determination of penicillin G, penicillin V and ampicillin in milk by high-performance liquid chromatography

Abstract

A rapid and simple method for the simultaneous determination of penicillin G (PCG), penicillin V (PCV) and ampicillin (ABPC) in milk is described. The retention behaviour of these β-lactam antibiotics in reversed-phase liquid chromatography with mobile phases containing sodium alkylsulphonate was studied. Good separations were obtained with methanol—water—0.2 M phosphate buffer (pH 4.0) (5:13:2) containing 11 m M sodium 1-heptanesulphonate and a LiChrosorb RP-18 column. The sample was pre-treated with a Sep-Pak C 8 cartridge. The peaks corresponding to each β-lactam antibiotics can be confirmed with the treatment using penicillinase. The recoveries from milk fortified with sodium PCG, potassium PCV and ABCP at levels of 0.5 and 0.1 μg/g each were generally better than 87% and the relative standard deviations were 1.17–4.98%. The detection limits correspond to 0.03 μg/g of these β-lactam antibiotics in milk.