Dissipation Dynamics, Terminal Residues and Dietary Risk Assessment of Two Isomers of Dimethacarb in Rice by HPLC-MS/MS.
Dissipation Dynamics, Terminal Residues and Dietary Risk Assessment of Two Isomers of Dimethacarb in Rice by HPLC-MS/MS.
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利用 HPLC-MS/MS 评估大米中灭虫威两种异构体的消散动力学、末端残留和膳食风险
DOI：
10.3390/foods10112615
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发表时间：
2021-10-28
期刊：
影响因子：
--
通讯作者：
Zhang Y
中科院分区：
文献类型：
--
作者：
Tang S;Meng X;Wang Y;Shi X;Feng T;Hu D;Zhang Y
二甲威是中国开发的一种氨基甲酸酯杀虫剂，含有甲基氨基甲酸3，5-二甲基苯酯（XMC）和甲基氨基甲酸3，4-二甲基苯酯（MPMC）异构体。中国已登记将二甲威用于水稻，但尚未报告二甲威在水稻中的残留或降解情况，也未确定水稻的最大残留限量。采用改进的QuEChERS样品前处理方法，建立了高效液相色谱-串联质谱（HPLC-MS/MS）同时测定水稻中2种烯虫威异构体的方法。糙米、稻壳和稻草中XMC和MPMC的平均回收率为71.69 ~ 100.60%，加标水平为0.01 ~ 1 mg/kg，相对标准偏差（RSD）为0.21 ~ 8.41%。田间试验表明，XMC和MPMC在稻草中的半衰期分别为4.08 ~ 4.23 d和3.48 ~ 3.69 d。在6个试验点，21 d后，XMC和MPMC在稻壳中的最终残留量分别为0.23-2.65 mg/kg和0.06-1.10 mg/kg，在糙米中的最终残留量分别为<0.01-0.16 mg/kg和<0.01-0.04 mg/kg。稻壳中XMC与MPMC含量的比值与50%二甲威乳油不同，说明XMC和MPMC的降解速率不同。XMC和MPMC的估计风险商（RQ）均小于30%。这些数据可为制定二甲威在水稻中的最大残留限量提供参考。
Dimethacarb is a carbamate insecticide developed in China that contains 3,5-dimethylphenyl methylcarbamate (XMC) and 3,4-dimethylphenyl methylcarbamate (MPMC) isomers. Dimethacarb has been registered for use in rice in China, but no residue or degradation of dimethacarb in rice has been reported and the maximum residue limits (MRLs) for rice have not been established. A versatile high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed with modified QuEChERS sample preparation to determine two isomers of dimethacarb in rice. The average recovery of XMC and MPMC in brown rice, rice husk, and rice straw ranged from 71.69 to 100.60%, with spike levels of 0.01 to 1 mg/kg and relative standard deviations (RSDs) of 0.21 to 8.41%. Field experiments showed that the half-lives of XMC and MPMC in rice straw were 4.08 to 4.23 days and 3.48 to 3.69 days, respectively. Final residues of XMC and MPMC in rice husk after 21 days of spraying at six sites ranged from 0.23–2.65 mg/kg and 0.06–1.10 mg/kg, and <0.01–0.16 mg/kg and <0.01–0.04 mg/kg in brown rice. The ratio of XMC to MPMC content in the rice husk differed from the original 50% dimethacarb EC, indicating the difference in the degradation rate of XMC and MPMC. The estimated risk quotient (RQ) for both XMC and MPMC was less than 30%. These data for residues from six representative locations could provide a reference for establishing the MRL of dimethacarb in rice.