Pre-column derivatization with trimethylsilyl diazomethane coupled with ASE-SPE-GC-MS/MS method for the quantification and validation of penicillin G residues in poultry tissues and pork

A novel, simple and high-sensitivity gas chromatography-tandem mass spectrometry (GC-MS/MS) method combined with external calibration was developed for the qualitative and quantitative determination of peni-cillin G residues in poultry tissues and pork. Samples were extracted by an ASE 350 apparatus with 0.2 mol/L phosphate buffer solution (pH 8.0) and purified on HLB solid-phase extraction (SPE) cartridges (60 mg/3 mL). Trimethylsilyl diazomethane (TMSD) was selected as the derivatization reagent for precolumn derivatization. The recoveries of analytes at the limit of quantitation (LOQ) and 25, 50 and 100 mu g/kg ranged from 80.67% to 96.18%, with RSDs below 3.17%. The determination coefficient (R2) values were above 0.9993 in the corre-sponding concentration range. The limits of detection (LODs) (S/N & GE; 3) and LOQs (S/N & GE; 10) ranged from 1.50 to 4.10 mu g/kg and 4.50-8.20 mu g/kg, respectively. In addition, the newly established method was implemented to analyze poultry tissues and pork purchased from a local market, demonstrating the sensitivity and applicability of the method.