苯醚甲环唑和吡唑醚菌酯在西瓜中的残留分析及膳食风险评价

目的评价苯醚甲环唑和吡唑醚菌酯在西瓜中的长期慢性和短期急性膳食摄入风险。方法于2018年进行1年10地规范残留试验,建立检测西瓜中苯醚甲环唑和吡唑醚菌酯残留的分析方法。样品经乙腈提取,加NaCl盐析,经无水MgSO4除水和PSA净化,用超高效液相色谱串联质谱法(ultra performance liquid chromatography tandem mass spectrometry, UPLC-MS/MS)分析,采用多反应离子监测模式(MRM)检测,正离子(ESI+)化,基质匹配外标法定量。结果目标物在一定质量浓度范围内具有良好的线性关系(r≥0.9991)。西瓜在0.01、0.05、0.5 mg/kg添加水平下,苯醚甲环唑平均回收率为92%~103%,相对标准偏差为0.9%~8.9%之间;吡唑醚菌酯的平均回收率为92%~95%, RSDs为1.7%~10.3%,定量限为0.01 mg/kg。膳食评估的结果:一般人群苯醚甲环唑的国家估算每日摄入量(the national estimated daily intake, NEID)为8.57μg/kg·bw/d,占日允许摄入量的85.7%;一般人群吡唑醚菌酯的NEID为18.72μg/kg·bw/d,占日允许摄入量的62.4%。短期急性膳食风险评苯醚甲环唑短期膳食摄入量(the national estimated short-term daily intake, NESTI)为2.98~4.26μg/kg·bw/d,占急性参考剂量(the acute reference dose, ARfD)的0.99%~1.42%,吡唑醚菌酯NESTI为6.23~8.90μg/kg·bw/d,占ARfD的12.46%~17.8%。我国规定的水果中苯醚甲环唑和吡唑醚菌酯最高MRL分别为2 mg/kg和4 mg/kg,该值对我国各类人群在水果中苯醚甲环唑暴露保护水平为1.44~11.24倍;吡唑醚菌酯暴露保护水平为2.16~16.86倍。结论苯醚甲环唑和吡唑醚菌酯长期慢性和短期急性膳食摄入风险较低,现有水果MRL对各类人群的暴露量在可接受的范围之内。

Residual analysis and dietary risk assessment of difenoconazole and pyraclostrobin in watermelon

Objective To evaluate the long-term, chronic and short-term, acute dietary intake risks of difenoconazole and pyraclostrobin in watermelon. Methods Residual specification experiment was carried out in 10 test locations in 2018. A method for residue analysis of difenoconazole and pyraclostrobin in watermelon was developed. The samples were extracted by acetonitrile, salted out by sodium chloride, dehydrated by anhydrous magnesium sulfate, then purified by primary secondary amine(PSA) sorbent, finally detected by ultra performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS) under the multiple-reaction monitoring mode(MRM) with positive electrospray ionization(ESI+) and quantified by external standard method. Results The recoveries were 92%-103%, and the relative standard deviations were 0.9%-8.9% when watermelon was added at 0.01, 0.05 and 0.5 mg/kg. The recoveries of pyraclostrobin were 92%-95% and RSDs were 1.7%-10.3%. The limits of quantitation were 0.01 mg/kg. The assessment results showed that the national estimated daily intake(NEDI) values of difenoconazole in the general population was 8.57 μg/kg·bw/d, accounting for 85.7% of the acceptable daily intake(ADI). NEDI of pyraclostrobin in the general population was 18.72 μg/kg·bw/d, accounting for 62.4% of the ADI. The national estimated short-term daily intake(NESTI) were 2.98-4.26 μg/kg·bw/d for difenoconazole, accounting for 0.99%-1.42% of the acute reference dose(ARfD). NESTI were 6.23-8.90 μg/kg·bw/d for pyraclostrobin, accounting for 12.46%-17.8% of the ARfD. The maximum MRL of difenoconazole and pyraclostrobin in fruits stipulated in China were 2 mg/kg and 4 mg/kg respectively, which were 1.44-11.24 times and 2.16-16.86 times as much as the difenoconazole and pyraclostrobin exposure level in all groups of Chinese residents. Conclusion It is a low risk of long-term chronic and short-term acute dietary intake for difenoconazole and pyraclostrobin. Existing MRL exposure to all groups of Chinese is within an acceptable range.