Assay for cephapirin and ampicillin in raw milk by high-performance liquid chromatography - integrated pulsed amperometric detection

摘要

A simple, rapid assay for the determination of beta-lactam antibiotic residues in milk using HPLC-integrated pulsed amperometric detection (IPAD) was developed. The method was used specifically for ampicillin and cephapirin. Since the analytes studied were detectable by ultraviolet detection, a comparison between IPAD and the latter was also carried out. Sample preparation schemes that involved extraction of antibiotics from the milk matrix and subsequent cleanup are discussed in detail. Extractionefficiencies for cephapirin were 74, 80 and 77% respectively at concentrations of 40, 20 and 10 ppb, and for ampicillin were 67, 78 and 75% respectively at concentrations of 20, 10 and 5 ppb.