建立了超高效液相色谱-串联质谱(UPLC-MS/MS)同时测定橙子、香蕉、苹果、菠萝中E-苯氧菌胺、嘧菌酯、醚菌酯、啶氧菌酯、吡唑醚菌酯和肟菌酯6种甲氧基丙烯酸酯类杀菌剂残留的方法.采用计算机辅助谱图解析软件ACD Lab/MS Fragmenter对质谱裂解路径进行了分析.样品经乙腈提取,氨基固相萃取柱(SupelClean LC-NH2)净化,采用ACQUITY UPLC BEH C18色谱柱(50 mm×2.1 mm,1.7μm)进行分离,以含0.1%(v/v)甲酸的10 mmol/L乙酸铵溶液和含0.1%(v/v)甲酸的乙腈溶液为流动相进行梯度洗脱,在电喷雾正离子模式下,采用多反应监测(MRM)模式监测,外标法定量.结果显示,6种甲氧基丙烯酸酯类杀菌剂在5~100μg/L(其中吡唑醚菌酯在1~20μg/L)范围内的相关系数(r2)均大于0.999.6种杀菌剂的加标回收率为60.4%~120%,相对标准偏差(RSD)为2.15%~15.1%(n=6).该法能满足橙子、香蕉、苹果和菠萝中6种甲氧基丙烯酸酯类杀菌剂残留量的检测要求.
A method was developed for the simultaneous determination of six strobilurin fungi-cide ( E-metominostrobin, azoxystrobin, kresoxim-methyl, picoxystrobin, pyraclostrobin and trifloxystrobin) residues in orange, banana, apple and pineapple samples by ultra performance liquid chromatography-tandem mass spectrometry ( UPLC-MS/MS ) . The fragmentation routes of all the compounds were explained by the aid of a fragment predicting software ACD Lab/MS Fragmenter. The samples were extracted by acetonitrile, then cleaned up by amino solid phase extraction cartridges ( SupelClean LC-NH2 ) . The extracts were separated on a ACQUITY UPLC BEH C18 column (50 mm×2. 1 mm, 1. 7μm) with gradient elution. Acetonitrile containing 0. 1%( v/v) formic acid and 10 mmol/L ammonium acetate containing 0. 1% ( v/v) formic acid were used as mobile phases. The samples were detected by electrospray ionization ( ESI)-MS/MS in positive ion and multiple reaction monitoring ( MRM ) mode, quantified by external standard method. Good linearities were obtained in the range of 5-100 μg/L ( for pyraclostrobin, 1-20μg/L) with correlation coefficients ( r2 ) greater than 0. 999. The recoveries ranged from 60. 4%to 120% with the relative standard deviations between 2. 15% and 15. 1% ( n=6) . The developed method can meet the inspection of the six strobilurin residues in the orange, banana, apple and pineapple samples.