戊唑醇及吡唑醚菌酯在玉米上的残留行为及风险评估

建立了玉米及其秸秆中戊唑醇和吡唑醚菌酯残留的分析方法。样品经乙腈提取,N-丙基乙二胺(PSA)和C18净化,利用超高效液相色谱-串联三重四极杆质谱仪(UPLC-MS/MS)检测。结果表明:在0.0025~0.1 mg/L范围内,戊唑醇及吡唑醚菌酯的峰面积与其质量浓度间呈良好的线性关系,R^2均大于0.99。鲜食玉米及成熟玉米籽粒在0.01、0.1和1 mg/kg,青玉米秸秆在0.01、0.1和2 mg/kg,成熟玉米秸秆在0.02、0.2和6 mg/kg添加水平下,戊唑醇在玉米及其秸秆中的添加回收率在75%~101%之间,相对标准偏差(RSD)在1.3%~6.0%之间;吡唑醚菌酯在玉米及其秸秆中的添加回收率在76%~101%之间,RSD在2.1%~8.4%之间。30%戊唑醇·吡唑醚菌酯悬浮剂以有效成分180 g/hm^2剂量施药3次,分别于末次施药后21和28 d采集的鲜食玉米及成熟玉米籽粒中,戊唑醇和吡唑醚菌酯残留量均低于定量限(0.01 mg/kg),也低于CAC、EU和EPA的最大残留限量值(MRL)。膳食风险评估结果表明:一般人群戊唑醇的国家估算每日摄入量为0.1545 mg,占日允许摄入量的8.2%;一般人群吡唑醚菌酯的国家估算每日摄入量为0.45 mg,占日允许摄入量的24.0%。因此,建议在玉米上使用30%戊唑醇·吡唑醚菌酯悬浮剂时,最高施药剂量为有效成分180 g/hm^2,最多施药3次,施药间隔为7 d,安全间隔期为21 d。

Residue behavior and dietary risk assessment of tebuconazole and pyraclostrobin in corn

A high efficient and simple methods for residue analysis of tebuconazole and pyraclostrobin in corn and stover (forage) were developed. The samples were extracted with acetonitrile, purified with primary secondary amine (PSA) and C₁₈, and detected by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The results showed that all the correlation coefficient of calibration curves were over 0.99 in ranged of 0.0025 to 0.1 mg/L. At three spiked concentration levels, the average recoveries of the tebuconazole varied from 75% to 101% with the relative standard deviations (RSDs) ranging from 1.3% to 6.0%; the average recoveries of the pyraclostrobin varied from 76% to 101% with the RSDs ranging from 2.1% to 8.4%. The 30% suspension concentrate (SC) of tebuconazole· pyraclostrobin was sprayed at 180 g a.i./ha for 3 times on corn. The residue of tebuconazole and pyraclostrobin in corn were less than 0.01 mg/kg at day 21 and 28 after the last application, which were below the maximum residue limits (MRLs) for tebuconazole and pyraclostrobin in the Codex Alimentarius Commission (CAC), European Union (EU) and Environmental Protection Agency (EPA). For general population, the national estimated daily intake of tebuconazole was 0.154 5 mg, accounting for 8.2% of the acceptable daily intake. The national estimated daily intake of pyraclostrobin was 0.45 mg, accounting for 24.0% of the acceptable daily intake. Thus, the dosage of 180 g a.i./ha for tebuconazole· pyraclostrobin 30% SC was recommended on corn with the preharvest interval at 21 days, and maximum application of three times with a 7-day interval between the sprays.