高效液相色谱-串联质谱快速测定饲料中硝基咪唑类药物及其代谢物残留

建立了高效液相色谱-串联质谱快速测定饲料中甲硝唑(MNZ)、甲硝唑代谢物(MNZOH)、二甲硝咪唑(DMZ)、二甲硝咪唑代谢物(HMMNI)、洛硝哒唑(RNZ)、异丙硝唑(IPZ)、异丙硝唑代谢物(IPZOH)残留的分析方法。样品经0.1 mol/L pH 8.0磷酸盐缓冲液和乙酸乙酯-丙酮(70∶30)提取,提取液经分散型固相萃取填料N-丙基乙二胺(PSA)净化后,再经正己烷脱脂,液-液分配净化,采用电喷雾电离源(ESI)正离子多反应监测(MRM)模式检测,氘代同位素内标法定量。该方法省去耗时的固相萃取过程,快速、简单、高效,7种目标分析物在2.0~100.0μg/L范围内线性关系良好,相关系数大于0.99,在5.0~25.0μg/kg范围内,3个加标水平的回收率为72.4%~95.6%,相对标准偏差(RSD)均小于12.5%;检出限为2.5μg/kg,定量下限为5.0μg/kg。

Rapid Determination of Nitroimidazoles and Their Metabolites Residues in Feeds by High Performance Liquid Chromatography-Tandem Mass Spectrometry

A high performance liquid chromatography-tandem mass spectrometric (HPLC-MS/MS) method was developed for the rapid determination of metronidazole (MNZ),metronidazole-OH (MNZOH),dimetridazole (DMZ),hydroxydimetridazole (HMMNI),ronidazole (RNZ),ipronidazole (IPZ),ipronidazole-OH(IPZOH) residues in feed.The samples were extracted with 0.1 mol/L pH 8.0 phosphate buffer and ethyl acetate-acetone (70 ∶ 30,by volume),then cleaned up with matrix solid-phase dispersant primary secondary amine (PSA).The extracts were defatted with hexane and cleaned up by liquid-liquid partition.The target compounds were detected by electrospray ionization (ESI) in positive mode using multiple reaction monitoring,and quantified by the isotope internal standard method.No solid-phase extract(SPE) procedure was adopted,which made sample preparation simple and efficient.The calibration curves for seven target compounds were linear in the range of 2.0-100.0 tμg/L with correlation coefficients more than 0.99.Average recoveries at spiked levels of 5.0-25.0 μ,g/kg were between 72.4％ and 95.6％,with relative standard deviation less than 12.5％.The limits of detection(LOD) were 2.5 μg/kg,and the limits of quantitation(LOQ) were 5.0 μg/kg.