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采用高效液相色谱-紫外检测器(HPLC-UVD)测定了烯啶虫胺在稻田水、土壤、水稻植株和糙米样品中的消解动态及最终残留。田水样品用二氯甲烷萃取;土壤样品用水提取后经二氯甲烷萃取;水稻植株和糙米样品依次用水、丙酮提取,提取液经液液萃取及柱层析净化;HPLC-UVD检测。当烯啶虫胺在田水和土壤中的添加水平为0.1～5 mg/L和0.1～5 mg/kg,在植株和糙米中的添加水平为0.2～5 mg/kg时,其平均添加回收率在77.2%～100.3%之间,相对标准偏差(RSD)在1.9%～12.9%之间。烯啶虫胺在稻田水、土壤、植株和糙米中方法的定量限(LOQ)分别为0.1 mg/L和0.1、0.2、0.2 mg/kg,检出限(LOD)分别为0.04 mg/L和0.04、0.08、0.08 mg/kg。温室模拟消解动态试验结果显示,以推荐使用高剂量的20倍(有效成分1 500 g/hm2)施药,烯啶虫胺在稻田水、土壤以及水稻植株中的消解动态规律均符合一级动力学方程,其半衰期分别为0.58、3.31及2.70 d,消解速率较快。最终残留试验表明,于大田分蘖期按推荐使用高剂量的1.5倍(有效成分112.5 g/hm2)分别施药3次和4次,间隔期为7 d,距最后一次施药7 d后采样,糙米中烯啶虫胺的残留量均低于LOD值(0.08 mg/kg)及日本规定的最大残留限量(MRL)值(0.5 mg/kg)。
The digestion kinetics and final residues of nitenpyram in paddy field water, soil, rice plants and brown rice samples were determined by HPLC-UV detector (HPLC-UVD). The water samples were extracted with dichloromethane. The soil samples were extracted with water and extracted with dichloromethane. The rice plants and brown rice samples were extracted with water and acetone sequentially. The extracts were purified by liquid-liquid extraction and column chromatography. The HPLC-UVD was used for the determination. When nitenpyram was added to field and soil at the levels of 0.1-5 mg / L and 0.1-5 mg / kg, respectively, the average addition of nitenpyram to plants and brown rice was 0.2-5 mg / kg Rates ranged from 77.2% to 100.3% with relative standard deviations (RSDs) between 1.9% and 12.9%. The limits of quantification (LOQ) of nitenpyram in rice water, soil, plant and brown rice were 0.1 mg / L and 0.1,0.2,0.2 mg / kg, respectively, and the limits of detection were 0.04 mg / L and 0.04, 0.08, 0.08 mg / kg. Dynamic simulation results of greenhouse simulated digestion showed that the dynamics of nitenpyram digestion in paddy field water, soil and rice plants were in good agreement with the first-order kinetic at the recommended 20-fold (1 500 g / hm 2 active ingredient) Learning equation, the half-life of 0.58,3.31 and 2.70 d, digestion rate faster. The final residue test showed that in the tillering stage of rice, 1.5 times (112.5 g / hm2) of the recommended dosage were applied three times and four times respectively, with an interval of 7 days, sampled 7 days after the last application, Residues of nitenpyram in brown rice were lower than the LOD value (0.08 mg / kg) and the Japanese maximum MRL value (0.5 mg / kg).