Fabric phase sorptive extraction of selected penicillin antibiotic residues from intact milk followed by high performance liquid chromatography with diode array detection

•Rapid fabric phase sorptive extraction (FPSE) was applied for penicillins in milk.•Protein precipitation was eliminated from the sample preparation work-flow.•FPSE simplified sample preparation without sacrificing quality of analytical data.•Model driven sorbent selection strategy led to correct phase without experimentation.•Robust FPSE sample preparation could be adopted as convenient routine QC practice.

Fabric phase sorptive extraction (FPSE), a novel sorbent-based microextraction method, was evaluated as a simple and rapid strategy for the extraction of four penicillin antibiotic residues (benzylpenicillin, cloxacillin, dicloxacillin and oxacillin) from cows' milk, without prior protein precipitation. Time-consuming solvent evaporation and reconstitution steps were eliminated successfully from the sample preparation workflow. FPSE utilizes a flexible fabric substrate, chemically coated with sol-gel derived, highly efficient, organic-inorganic hybrid sorbent as the extraction medium. Herein short-chain poly(ethylene glycol) provided optimum extraction sensitivity for the selected penicillins, which were analysed using an RP-HPLC method, validated according to the European Decision 657/2002/EC. The limit of quantitation was 10 μg/kg for benzylpenicillin, 20 μg/kg for cloxacillin, 25 μg/kg dicloxacillin and 30 μg/kg oxacillin. These are a similar order of magnitude with those reported in the literature and (with the exception of benzylpenicillin) are less than the maximum residue limits (MRL) set by European legislation.