二甲四氯异辛酯及其代谢物二甲四氯在玉米中的残留量及风险评估

目的 明确鲜食玉米和成熟期籽粒中2甲4氯异辛酯及其代谢物2甲4氯残的残留水平,评价其膳食摄入风险。方法 以改进的QuEChERS前处理方法同时提取玉米中2甲4氯异辛酯和2甲4氯残留物,分别用用气相色谱-串联质谱法和液相色谱-串联质谱法检测2甲4氯异辛酯和2甲4氯的残留量。结果 2甲4氯异辛酯和2甲4氯仪器最小检出量(LOD)分别为2×10_^-12 g和5×10_^-12 g；在鲜食玉米、成熟期籽粒的最小检出浓度( LOQ)均为0.005 mg/kg,整体回收率为71%~114%,相对标准偏差(RSD)为1.2%~7.2 %。结论 该方法的准确度和精密度良好,2甲4氯异辛酯在鲜食玉米中残留量为<0.005~0.032 mg/kg,成熟期籽粒中残留量为<0.005~0.022 mg/kg,均<0.05 mg/kg；代谢物2甲4氯在鲜食玉米、成熟期籽粒中的最终残留量均<0.005 mg/kg；玉米中2甲4氯异辛酯及其代谢物2甲4氯残的膳食风险较低。

Residue and risk assessment of 2-methyl-4-chlorophenoxyacetic acid-isooctyl and its metabolite 2-methyl-4-chlorophenoxyacetic acid in corn

ABSTRACT: Objective This study aims to determine the residual level of 2 methyl 4 chloro isooctyl ester and its metabolite 2 methyl 4 chloro residue in fresh and mature corn grains, and further to evaluate the dietary intake risk. Methods The residues of 2-methyl-4-chloro-isooctyl ester (MCPA-isooctyl) and 2-methyl-4-chloro-1-octyl ester (MCPA) in corn were firstly extracted by the improved QuEChERS pretreatment method and detected by GC-MS/MS and by LC-MS/MS, respectively. Results The LOD of MCPA-isooctyl and MCPA was 2 × 10-12g and 5 × 10-12g, respectively, and the LOQ was 0.005mg/kg. The average recoveries ranged from 71% to 114%, and the RSD was 1.2% ~ 7.2%. Conclusions The accuracy and precision of this method are good. The final residue of MCPA-isooctyl in fresh corn and mature corn were < 0.005-0.032mg/kg and 0.005-0.022mg/kg, respectively. The final residue of MCPA in fresh corn and mature corn is < 0.005mg/kg. The dietary risk of MCPA-isooctyl and MCPA residue in corn was low.