冻干鲤鱼粉中恩诺沙星和环丙沙星残留测定的两种前处理方法比较

Comparison of Two Pretreatment Methods for UPLC-MS/MS Determination of Enrofloxacin and Ciprofloxacin Residues in Freeze-dried Carp Meal

采用固相萃取和液液萃取结合超高效液相色谱-串联质谱法(UPLC-MS/MS),对冻干鲤鱼粉中恩诺沙星和环丙沙星残留量进行测定,比较两种前处理方法的测定结果。固相萃取法:样品经EDTA-Mcllvaine缓冲溶液提取,HLB固相萃取柱净化,氮气浓缩;液液萃取法:样品经酸性乙腈溶液提取,正己烷液液萃取净化,旋转蒸发浓缩。两种方法的提取液浓缩定容后,以超高效液相色谱-串联质谱仪测定,外标法定量。固相萃取和液液萃取法的回收率分别为95%～112%和75%～90%,RSD分别为2.9%～7.4%和1.0%～4.6%,检出限分别为1.0μg/kg和0.1～0.2μg/kg。结果表明,两种方法简便快速、重现性好、选择性强,均适用于鱼肉和冻干鲤鱼粉中恩诺沙星和环丙沙星残留的测定。

Sample pretreatment was achieved by two different methods,solid-phase extraction and liquid-liquid extraction,before the analysis of enrofloxacin and ciprofloxacin residues in freeze-dried carp meal on UPLC-MS/MS.The analytical results were compared to examine if the two pretreatment methods influence the accuracy of determination.The solid-phase extraction procedure was composed of extraction with EDTA-Mcllvaine buffer,clean-up on HLB column and blowing to dryness under nitrogen gas.Liquid-liquid extraction pretreatment was achieved sequentially through extraction with acidified acetonitrile followed by clean-up by liquid-liquid extraction with n-hexane and evaporation to dryness in a rotary evaporator.Both residues were dissolved in 1 mL of mixed solution of acetonirile and 0.2%formic acid（1：9,V/V）prior to injection into UPLC-MS/MS system.For the quantitation of enrofloxacin and ciprofloxacin,external standard method was used.Average spike recoveries of solid-phase extraction and liquid-liquid extraction ranged from 95%to 112%and from 75%to 90%,with relative standard deviations between 2.9%and 7.4%and between 1.0%and 4.6%,respectively（n=6）.The limits of detection（LOD）of solid-phase extraction for the two analytes were both 1.0μg/kg,and the LOD of liquid-liquid extraction was 0.1μg/kg for enrofloxacin and 0.2μg/kg for ciprofloxacin.As a conclusion,both methods are characterized by simplicity,rapidity,good reproducibility and high selectivity,and therefore can be used to determine enrofloxacin and ciprofloxacin residues in fish meat and freeze-dried carp meal.