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建立了对氯苯氧乙酸钠在荔枝和土壤中的残留分析方法,并在广州和南宁进行了8%对氯苯氧乙酸钠可溶性粉剂在荔枝上残留的田间试验,研究了对氯苯氧乙酸钠在荔枝和土壤中的消解动态和最终残留量。样品用碱溶液提取,盐酸调节p H值至2.5后乙酸乙酯萃取,采用高效液相色谱二极管阵列紫外检测器(HPLC-PDA)检测。结果表明:在0.01、0.1和1 mg/kg 3个添加水平下,对氯苯氧乙酸钠在荔枝和土壤中的平均回收率为81%~85%,相对标准偏差(RSD)为1.9%~4.6%,检出限(LOD)为0.005 mg/kg,定量限(LOQ)为0.01 mg/kg。田间试验结果表明:8%对氯苯氧乙酸钠可溶性粉剂在荔枝和土壤中的半衰期分别为3.2~5.9 d和15.2~20.6 d,属易降解农药。最终残留量测定结果显示:8%对氯苯氧乙酸钠可溶性粉剂按有效成分20和30 mg/L分别施药2次,广州和南宁两地收获期荔枝中对氯苯氧乙酸钠的残留量均<0.01 mg/kg。
A method of residue analysis of p-chlorophenoxyacetate in litchi and soil was established. Field experiments were conducted in Guangzhou and Nanning on the residue of 8% p-chlorphenoxyacetate soluble powder on litchi. The effects of p-chlorophenoxyacetic acid Digestion Dynamics and Final Residues of Sodium in Litchi and Soil. The sample was extracted with alkaline solution, hydrochloric acid adjusted p H value to 2.5 and extracted with ethyl acetate, detected by high performance liquid chromatography with diode array UV detector (HPLC-PDA). The results showed that the average recoveries of p-chlorophenoxyacetate in litchi and soil were 81% ~ 85% and the relative standard deviations (RSDs) were 1.9% ~ 3% at the three levels of 0.01, 0.1 and 1 mg / 4.6%, the limit of detection (LOD) was 0.005 mg / kg and the limit of quantification (LOQ) was 0.01 mg / kg. Field trials showed that the half-lives of 8% p-chlorophenoxyacetate soluble powder in litchi and soil were 3.2-5.9 d and 15.2-20.6 d, respectively, which were easily degradable pesticides. The results of the determination of the final residues showed that 8% p-chlorophenoxyacetate soluble powder was applied twice at the effective components of 20 and 30 mg / L, respectively. The residues of p-chlorophenoxyacetate in the litchi of Guangzhou and Nanning All <0.01 mg / kg.