龙眼中吡唑醚菌酯及其代谢物BF-500-3残留分析

Residue of pyraclostrobin and its metabolite BF-500-3 in Dimocarpus longan Lour.

采用高效液相色谱-串联质谱(HPLC-MS/MS)检测技术,建立了吡唑醚菌酯及其代谢物BF-500-3在龙眼中残留分析方法,并依据"农作物中农药残留试验准则",开展了30%吡唑醚菌酯悬浮剂(SC)在广东省广州市和云南省玉溪市两地龙眼上的田间残留试验,研究了吡唑醚菌酯及其代谢物BF-500-3在龙眼中的降解和转化规律。样品采用乙腈提取,经PSA和C18吸附剂净化,HPLC-MS/MS检测分析。结果表明:在0.001、0.1及2 mg/kg添加水平下,吡唑醚菌酯和BF-500-3在龙眼中的平均回收率为84%~96%,相对标准偏差(RSD)为3.8%~6.7%,检出限(LOD)为0.25×10^-3 mg/kg,定量限(LOQ)为0.001 mg/kg。田间试验结果显示:采用30%吡唑醚菌酯SC于龙眼初果期开始施药,施药剂量为有效成分375 mg/kg,施药3~4次,施药间隔7~10 d条件下,距末次施药后5、7、10 d分别取样测定,龙眼中吡唑醚菌酯及其代谢物BF-500-3的残留量分别为0.11~0.72和0.011~0.071 mg/kg。研究结果可为指导吡唑醚菌酯在田间的科学合理使用及制定其在龙眼上的最大残留限量(MRL)提供参考。

A sensitive method for the determination of pyraclostrobin and its metabolite BF-500-3 in longan(Dimocarpus longan Lour.)was developed based on high performance liquid chromatographytandem mass spectrometry(HPLC-MS/MS)technique.According to"Guideline for the testing of pesticide residues in crops",field tests conducted in Guangzhou City of Guangdong Province and Yuxi City of Yunan Province.The residual behavior of pyraclostrobin parent and its metabolite based on longan field trials was investigated.The results showed good average recoveries of 84%-96%,with relative standard deviations of 3.8%-6.7%,at the spiked levels of 0.001,0.1 and 2 mg/kg in longan.The limit of detection(LOD)was 0.25×10^-3 mg/kg and the limit of quantification(LOQ)was 0.001 mg/kg.When pyraclostrobin was applied 3-4 times at the dosage of 375 mg/kg with the interval period of 7-10 days,and pre-harvest interval of 5,7 and 10 days,the residues of pyraclostrobin parent and BF-500-3 in longan were 0.11-0.72 mg/kg and 0.011-0.071 mg/kg,respectively.This study would be helpful to guide the scientific and efficient utilization of this fungicide.Because of the absence of maximum residue limit(MRL)of pyraclostrobin in longan,these results could provide references to facilitate the setting of MRL of pyraclostrobin.