Determination of diazepam and oxazepam in freshwater fishes by QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry
Objective The phenomenon of drug residues in aquatic products is becoming increasingly serious.Diazepam and oxazepam are commonly used sedative drugs in freshwater fish,and long-term consumption will cause great harm to the human body.This study established and optimized a QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry(QuEChERS-UPLC-MS)method for the determination of diazepam and oxazepam drug residues in freshwater fish.Methods The sample was extracted with acetonitrile,subjected to ultrasonic extraction,purified by QuEChERS method(100 mg PSA,50 mg Ci8,150 mg MgSO4),and finally eluted with methanol-0.1％formic acid water,separated by chromatography column ACQUITY UPLC BEH C18(50 mm×2.1 mm,1.7 μm),scanned by positive ions,detected by electrospray tandem mass spectrometry multi reaction monitoring(MRM),and quantified by internal standard method.Results The linear relationship between diazepam and oxazepam was good within the range of 0.05-50.00 μg/L(r＞0.999).The limits of detection(LOD)and quantification(LOQ)of diazepam and oxazepam were 0.5 and 1.0 μg/kg,respectively.The mean recoveries of diazepam and oxazepam ranged from 81.1％to 98.3％at the spiked levels of 1,2,and 20 times detection limits(n=6),with the relative standard deviations(RSD)less than 10％.Conclusion The pre-treatment process of this method is convenient,and fast,simple in steps,with good reproducibility.Using 0.1％formic acid water as the mobile phase significantly improves the response value of the tested substance.This method is suitable for the qualitative and quantitative analysis of diazepam and oxazepam in freshwater fishes.
DiazepamOxazepamQuEChERSUltra high performance liquid chromatography-tandem mass spectrometry
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