三种有机磷农药在双孢蘑菇及其栽培基质中的残留动态

为明确二嗪磷、毒死蜱和辛硫磷3种有机磷农药在双孢蘑菇栽培过程中的残留动态规律，采用在工厂化双孢蘑菇栽培基质 (覆土和培养料) 中拌料施药的方式，开展了田间试验，运用QuEChERS净化前处理技术结合UPLC-MS/MS分析，检测了3种农药在双孢蘑菇子实体和栽培基质中的残留动态。结果表明:建立的双孢蘑菇子实体、覆土和培养料3种基质中3种有机磷农药的液相色谱-串联质谱检测方法，经验证，在二嗪磷分别以0.000 3、0.003、0.1 mg/kg为添加水平，毒死蜱和辛硫磷分别以0.000 6、0.006、0.1 mg/kg为添加水平下，3种有机磷农药在双孢蘑菇、覆土和培养料3种基质中的平均回收率为76%~108%，相对标准偏差为2.2%~13%。检出限分别为:二嗪磷0.000 1 mg/kg、毒死蜱和辛硫磷均为0.000 2 mg/kg，定量限分别为:二嗪磷0.000 3 mg/kg、毒死蜱0.0006 mg/kg和辛硫磷0.000 6 mg/kg。在2 和10 mg/kg两个施药水平下，二嗪磷、毒死蜱和辛硫磷在双孢蘑菇栽培基质中的消解规律均符合一级反应动力学方程，在培养料中的消解半衰期分别为5.2、10.6、13.6 d和5.6、11.4、12.3 d；在覆土中的消解半衰期分别为25.9、41.7、27.2 d和41.7、48.1、36.8 d，且在培养料中的消解快于在覆土中的。在施药剂量不超过10 mg/kg的条件下，在双孢蘑菇子实体中毒死蜱残留量最高，为0.014 mg/kg，超过了欧盟规定的最大残留限量(MRL)标准，其余均低于现行日本、欧盟和美国规定的MRL值。

Residual dynamics of three organophosphorus pesticides in Agaricus bisporus fruits and cultivation substrates

To investigate the residual behaviors of three organophosphorus pesticides in the cultivation of Agaricus bisporus, field trials were conducted by applying diazinon, chlorpyrifos and phoxim into the culture media (soil and substrates). By optimizing the pretreatment method and instrument conditions, determination method of three organophosphorus pesticide in mushroom, soil and substrates using liquid chromatography-tandem mass spectrometry was established. Samples were extracted with acetonitrile, purified by QuEChERS and detected with UPLC-MS/MS. In mushroom, soil and cultivation substrates, Recoveries of diazinon at the spiked levels of 0.0003, 0.003, 0.1 mg/kg and the recoveries of chlorpyrifos and phoxim at the spiked levels of 0.0006, 0.006, and 0.1 mg/kg, were 76%-108%, and the relative standard deviation was 2.2%-13%. The limits of detection (LOD) of diazinon, chlorpyrifos and phoxim were 0.0001, 0.0002, 0.0002 mg/kg, respectively, and the limits of quantitation (LOQ) were 0.0003, 0.0006, 0.0006 mg/kg, respectively. At all application rates, three pesticides dissipated following the first-order degradation kinetics. The dissipation half-lives of diazinon, chlorpyrifos and phoxim in cultivation substrates were 5.2 d, 10.6 d, 13.6 d and 5.6 d, 11.4 d, 12.3 d and those in soil were 25.9 d, 41.7 d, 27.2 d and 41.7 d, 48.1 d, 36.8 d, respectively. The dissipation of three pesticides in soil was faster than that in the cultivation substrates. Chlorpyrifos residue in mushroom fruits was up to 0.014 mg/kg at the application rate of 10 mg/kg, which exceeded the European maximum residue limits standard (MRL). The others were lower than the Japanese, European and America MRL values.