水稻中除草剂氯氟吡氧乙酸异辛酯和氰氟草酯的检测方法及其储藏稳定性研究

Detection method of cyhalofop-butyl and fluroxypyr-meptyl herbicides in rice and study on its storage stability

中文关键词:  氯氟吡氧乙酸异辛酯  氰氟草酯  水稻  储存稳定性  膳食风险

英文关键词:fluroxypyr-meptyl  cyhalofop-butyl  rice  storage stability  dietary risk

中文摘要:

      目的 探究26%氰氟草酯·氯氟吡氧乙酸异辛酯乳油在水稻上的残留行为, 对其储藏稳定性和膳食摄入风险进行评估。方法 待测试样经乙酸乙腈提取, N-丙基乙二胺(primary secondary amine, PSA)、C18和石墨化碳黑(graphitized carbon black, GCB)净化, 再经高效液相色谱-串联质谱法(high performance liquid chromatography-tandem mass spectrometry, HPLC-MS/MS)多反应监测(multiple reaction monitoring, MRM)模式扫描, 基质匹配标准曲线外标法定量。2018年在9地进行田间残留实验, 并且进行6个月的储藏实验, 获得氯氟吡氧乙酸、氰氟草酯和氰氟草酸在水稻上的残留实验中值(supervised trials median residue, STMR)、降解率, 对膳食摄入风险进行评估。结果 氯氟吡氧乙酸、氰氟草酯和氰氟草酸在0.005~0.5 mg/kg范围内具有良好的线性关系, 相关系数(r)为0.9962~0.9997, 3种待测物在水稻中的回收率为80.5%~98.4%, 相对标准偏差(relative standard deviation, RSD)为0.7%~9.2%, 定量限为0.050 mg/kg。在6个月储藏实验期间, 3种待测物在稻谷及水稻植株的降解率低于30%。膳食风险评估表明: 普通人群氯氟吡氧乙酸异辛酯、氰氟草酯的国家估计每日摄入量分别为0.0596 mg和0.0120 mg, 膳食摄入风险评估分别为4.73%和1.90%。结论 该检测方法操作简便、前处理速度快、精密度和灵敏度高, 可以满足对复合农药残留分析检测的要求。氯氟吡氧乙酸、氰氟草酯和氰氟草酸在-20 ℃冰箱6个月储藏稳定, 其在水稻上的残留对消费者不会产生不可接受的风险。

英文摘要:

      Objective To explore the residue behavior of 26% cyhalofop-butyl·fluroxypyr-meptyl emulsion in rice, and then evaluate the storage stability and the risk of dietary intake. Methods Samples were extracted with acetic acid and acetonitrile, cleaned up with primary secondary amine (PSA), C18 and graphitized carbon black (GCB), and then analyzed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) in multiple reaction monitoring (MRM) mode with the matrix-matched calibrations method. Filed residual trials on 9 sites in 2018 and storage experiment for 6 months. The supervised trials median residue (STMR) and degradation rates of cyhalofop-butyl, cyhalofop acid and fluroxypyr in rice were acquired, and then the risk assessment of dietary intake was conducted. Results There existed good linearities for all analytes in the range of 0.005?0.5 mg/kg with their correlation coefficients (r) of 0.9962-0.9997, and the recoveries for 3 kinds of determinands in rice were in the range of 80.5%-98.4% with relative standard deviation (RSD) of 0.7%?9.2%. The limit of quantitation was 0.050 mg/kg. During the 6 months storage experiment, the degradation rates of cyhalofop-butyl, cyhalofop acid and fluroxypyr in rice and rice plants were lower than 30%. The result of the dietary risk assessment revealed that the national estimated daily intake of fluroxypyr-meptyl and cyhalofop-butyl was 0.0596 mg and 0.0120 mg respectively, with the risk quotient of 4.73% and 1.90% respectively for general population. Conclusion This method is simple to operate, fast to pretreat, high sensitive and accurate, and can meet the requirements of compound pesticides residues analysis and detection. The pesticides were stored stably in the refrigerator at ?20 ℃ for 6 months, and they will not cause unacceptable risk to the health of the consumers.