联苯肼酯及其代谢物和哒螨灵在茄子中的最终残留量及储藏稳定性研究

Study on the final residues and storage stability of bifenazate and its metabolites and pyridaben in eggplant

为探究哒螨灵、联苯肼酯及其代谢物在茄子上的储存稳定性及其残留行为,在湖北、四川等8地开展哒螨灵、联苯肼酯及联苯肼酯二氮烯在茄子上的规范残留田间试验,样品经乙酸乙腈提取,再由N-丙基乙二胺吸附剂(PSA)和十八烷基键合硅胶吸附剂(C18)分散固相萃取净化,过膜后,用超纯水-乙腈作为流动相进行梯度洗脱,通过基质标准曲线外标法进行定量。结果表明,在3个添加水平下(0.05(0.02)、0.1、0.5(0.2)mg·kg^(-1))其回收率为89.0%~107.0%,相对标准偏差为3.0%~12.7%,定量检出限(LOQ)分别为0.050 mg·kg^(-1)、0.020mg·kg^(-1)和0.020 mg·kg^(-1)。最终残留试验表明,45%联肼·哒螨灵悬浮剂,用药量为制剂45 m L·hm^(-2)(有效成分用量303.75 g·hm^(-2)),施药2次,施药间隔7 d,采收间隔期为7 d、10 d,收获茄子中哒螨灵的残留量均小于0.053 mg·kg^(-1),联苯肼酯的残留量均小于0.040 mg·kg^(-1)。稳定性试验也表明,哒螨灵、联苯肼酯及其代谢物在–20℃冰箱储藏180d稳定。结论是45%联肼·哒螨灵悬浮剂在茄子上残留量极低。

To explore the storage stability and residue behavior of pyridaben,bifenazate and its metabolites in eggplant,field tests on standardized residues of pyridaben,bifenazate,and bifenazate-diazene on eggplant were carried out in 8 areas of Hubei and Sichuan provinces.The samples were extracted by acetic acid and acetonitrile,and then cleaned by N-propylethylenediamine adsorbent(PSA)and octadecyl bonded silica gel adsorbent(C;)dispersion solid phase extraction.After passing through the membrane,the gradient elution was carried out with ultrapure water-acetonitrile as the mobile phase,and the quantification was carried out by the matrix standard curve external standard method.Results under 3 addition levels(0.05(0.02),0.1,0.5(0.2)mg·kg^(-1)),the recovery rate was 89.0%-107.0%,the relative standard deviation(RSD)was 3.0%-12.7%,and the quantitative limits of detection(LOQ)was 0.050 mg·kg^(-1),0.020 mg·kg^(-1),0.020 mg·kg^(-1),respectively.The final residue test showed that the 45%of suspension agent of Biphenyl hydrazine and pyridaben with the dosage of 45 m L·hm^(-2)(a.i 303.75g·hm^(-2))was applied twice,and the interval of application was 7 d,and the intervals of harvest were 7 d and 10 d.The residues of pyridaben in harvested eggplant were all less than 0.053 mg·kg^(-1),and the residues of bifenazate were all less than 0.040 mg·kg^(-1).The stability test also showed that pyridaben,bifenazate and its metabolites were stable when stored in refrigerator at-20℃for 180 d.The conclusion is that residue amount of 45%of suspension agent of Biphenyl hydrazine and pyridaben concentrate on eggplant was extremely low.