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

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

目的明确鲜食玉米和籽粒中二甲四氯异辛酯及其代谢物二甲四氯(methyl-4-chlorophenoxyacetic acid,MCPA)的残留水平,评价其膳食摄入风险。方法开展75%二甲四氯异辛酯乳油在玉米的田间试验,分别用气相色谱-串联质谱法和高效液相色谱-串联质谱法对玉米中的二甲四氯氯异辛酯和MCPA残留量进行测定。结果二甲四氯氯异辛酯和MCPA在鲜食玉米和籽粒样品中的回收率为74%~107%,相对标准偏差(RSD)为1.7%~7.2%;二甲四氯异辛酯在鲜食玉米样品中的残留量为<0.005~0.032mg/kg,在籽粒样品中的残留量为<0.005~0.022 mg/kg;代谢物MCPA在鲜食玉米和籽粒样品中的最终残留量均<0.005 mg/kg。结论二甲四氯异辛酯和代谢物MCPA的风险概率分别为0.41%和0.49%,二甲四氯异辛酯在玉米田中施药剂量为225~450 gai/ha,最多使用1次时,对一般人群健康无风险。

Objective To determine the residual levels of 2-methyl 4-chlorophenoxyacetic acid-isooctyl and its metabolite 2-methyl 4-chloride(MCPA) in fresh corn and grains, to evaluate the dietary intake risk. Methods Field trials of 75% 2-methyl-4-chlorisooctyl oil in maize were carried out. The residues of 2-methyl 4-chloroisooctyl and MCPA in corn were determined by gas chromatography-tandem mass spectrometry and high performance liquid chromatography-tandem mass spectrometry respectively. Results The average recoveries of MCPA-isooctyl and MCPA ranged from 74% to 107%, and the RSD was 1.7%-7.2%. The final residue of MCPA-isooctyl in fresh corn and mature corn were <0.005-0.032 mg/kg and 0.005-0.022 mg/kg, respectively. The final residue of MCPA in fresh corn and mature corn was <0.005 mg/kg. Conclusion The risk probability of MCPA-isooctyl and the metabolite MCPA are 0.41% and 0.49% respectively. The MCPA-isooctyl is safe to the general population if it is used once at most and the dose was 225-450 gai/ha.