杀菌剂吡唑醚菌酯在大白菜上的残留动态

采用高效液相色谱紫外法测定大白菜中杀菌剂吡唑醚菌酯的残留量，对吡唑醚菌酯在河北、湖南两地大白菜中的残留规律进行了研究。结果表明，该方法最低检出浓度为0.04 mg?kg-1，残留量在0.04～2.00 mg?kg-1范围内的添加回收率为70%～106%，变异系数为6.6%～10.0%。两地残留动态试验结果显示：吡唑醚菌酯在大白菜上的半衰期分别为2.97 d和3.34 d|按推荐剂量12.50 g?（667 m2）-1和1.5倍剂量18.75 g?（667 m2）-1施药3～4次，距最后1次施药7 d，吡唑醚菌酯在大白菜中的残留量为0.96～2.70 mg?kg-1。

Residue Dynamics of Fungicide Pyraclostrobin on Chinese Cabbages

Liquid chromatography with UV detection was used to determine pyraclostrobin residues in Chinese cabbage〔Brassica compestris L. ssp. pekinensis（Lour）Olsson〕．The dynamics of degradation of pyraclostrobin residues in Chinese cabbages in Hebei and Hunan Provinces were studied．The results showed that the limit of determination was 0.04 mg?kg-1．The recoveries were 70%～106% and coefficients of variation were 6.6%～10% between the concentration of 0.04～2.00 mg?kg-1．The results indicated that the half lives of pyraclostrobin in Chinese cabbages in Hebei and Hunan were 2.97 d and 3.34 d，respectively．According to the research findings，when pyraclostrobin being applied 3 and 4 times to Chinese cabbage fields with dosages of active ingredient of 187.50 and 281.25 g?hm-2，the residues of pyraclostrobin in Chinese cabbages 7 days after the last application were between 0.96～2.70 mg?kg-1．