高效液相色谱-串联质谱法测定荔枝花粉和花蜜中腈菌唑和苯醚甲环唑残留

采用改良的QuEChERS-高效液相色谱-串联质谱(HPLC-MS/MS)技术,建立了荔枝花粉和花蜜中2种主要杀菌剂腈菌唑和苯醚甲环唑的测定方法。花粉和花蜜样品均由乙腈提取,花粉样品经0.9 g无水硫酸镁、0.15 g N-丙基乙二胺(PSA)和0.15 g十八烷基键合硅胶(C_(18))吸附剂净化,花蜜样品由0.9 g无水硫酸镁和0.15 g PSA净化。采用Poroshell-120 EC-C_(18)色谱柱分离,以0.1%(v/v)甲酸水溶液-乙腈(25∶75,v/v)为流动相等度洗脱,在电喷雾离子(ESI)源、正离子扫描和选择离子监测模式下进行检测,基质匹配标准溶液法定量。结果显示:腈菌唑和苯醚甲环唑在1~100μg/L范围内线性关系良好,相关系数(r2)均大于0.999 0;腈菌唑和苯醚甲环唑的检出限(LOD)分别为0.25μg/kg和0.50μg/kg,定量限(LOQ)分别为0.83μg/kg和1.7μg/kg;腈菌唑和苯醚甲环唑在荔枝花粉和花蜜样品中的平均加标回收率分别为87.0%~95.2%和90.1%~96.4%,相对标准偏差(RSD)分别为1.2%~3.6%和0.7%~4.1%。该法快速、简便、灵敏,可用于荔枝花粉和花蜜样品中腈菌唑和苯醚甲环唑的痕量测定,可为蜜蜂等授粉昆虫的暴露性风险评估提供技术支持。

Determination of myclobutanil and difenoconazole residues in pollen and honey of litchi by high performance liquid chromatography-tandem mass spectrometry

An effective method was developed for the determination of two major fungicides including myclobutanil and difenoconazole residues in pollen and honey of litchi by modified QuEChERS-high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The pollen and honey samples were all extracted by acetonitrile, the pollen samples were cleaned-up by 0.9 g anhydrous magnesium sulfate (MgSO₄), 0.15 g primary secondary amine (PSA) and 0.15 g C₁₈; the honey samples were cleaned-up by 0.9 g MgSO₄ and 0.15 g PSA. The 0.1% (v/v) formic acid aqueous solution-acetonitrile (25:75, v/v) were used as the mobile phases. The extracts were separated on a Poroshell-120 EC-C₁₈ chromatographic column, the positive electrospray ion (ESI⁺) source and selected ion monitoring (SIM) mode were used. The analytes were quantified by the matrix matching standard solutions. The matrix matched standard solutions of myclobutanil and difenoconazole showed good linearities in the range of 1-100 μg/L, and the correlation coefficients (r²) were all above 0.9990. The limits of detection (LODs) of myclobutanil and difenoconazole were 0.25 μg/kg and 0.50 μg/kg, respectively. The limits of quantification (LOQs) of myclobutanil and difenoconazole were 0.83 μg/kg and 1.7 μg/kg, respectively. The average recoveries of myclobutanil and difenoconazole in pollen and honey samples were 87.0%-95.2% and 90.1%-96.4% with the relative standard deviations of 1.2%-3.6% and 0.7%-4.1%, respectively. The method is quick, easy and sensitive, and it is suitable for the rapid determination and trace analysis of myclobutanil and difenoconazole in pollens and honeys of litchi. The method can provide data support for the exposure risk assessment of bees and other pollination insects.