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This study developed a rapid multi-class method for determining 29 antibiotic residues in crawfish using liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. A quick and affordable extraction method was employed, and sample preparation was performed using a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) technique. The extraction process involved adding acetonitrile to crawfish samples. The sample was homogenised with a solution of sodium citrate buffer and sodium EDTA, followed by a cleanup step. The method was validated according to European Union (EU) guidelines 2002/657/EC. The limit of quantitation (LOQ) for all antibiotics was 5 µg/kg, except for flumequine and trimethoprim, which had LOQs of 2.5 µg/kg. The LOQ for the tetracycline group was 25 µg/kg, and for chloramphenicol, it was 0.015 µg/kg. The average recoveries at different concentration levels varied between 60–120%. The precision, expressed as repeatability and reproducibility, was calculated to be less than 16%. Thirty crawfish samples collected from local Egyptian market were monitored for antibiotic residues. The results revealed contamination with antibiotics belonging to three different groups. Of the thirty samples, 27% were contaminated with ciprofloxacin and enrofloxacin, 17% with chlortetracycline and oxytetracycline, 7% with oxolinic acid, and 3% with sulphamethazine. The applicability of the developed method was proven through successful proficiency testing. The developed method met performance criteria and is suitable for monitoring these antibiotics in crawfish.
Nermine Gad (Wed,) studied this question.