露地黄瓜啶氧菌酯的残留分析及黄瓜个体残留水平的差异

在天津主要蔬菜产区对新型杀菌剂啶氧菌酯在露地黄瓜上的残留状况进行研究,并对黄瓜个体的差异与农药残留量之间的关系进行分析和评价,为啶氧菌酯在黄瓜上的污染控制及其合理使用提供科学依据。首先建立了基于QuEChERS方法结合液相色谱法的黄瓜中啶氧菌酯残留量分析检测方法,在0.02 mg/kg、0.2 mg/kg和1 mg/kg 3个添加水平上啶氧菌酯的平均回收率为76.5%~93.4%,相对标准偏差均小于10%,其准确度和精确度均符合我国农药残留试验准则要求。在对黄瓜中啶氧菌酯的残留状况进行研究时发现,施药后1 d内药剂消解迅速,之后消解速率逐渐趋缓,3 d时残留量已降至欧盟制定的最大残留限量(0.05 mg/kg)以下。而在对黄瓜个体中啶氧菌酯残留量的差异进行研究时发现,平均残留量(0.639 mg/kg)大于残留量中值(0.508 mg/kg),黄瓜个体的质量与其中啶氧菌酯的残留量没有明显的关系。

Residue Analysis of Picoxystrobin in Cucumber under Field Condition and Individual Variations of Residue Levels

The residue of picoxystrobin in cucumber under field condition was investigated in the main vegetable producing areas of Tianjin,and the relationship between the individual variations of cucumber and the amount of pesticide residues was analyzed and evaluated as well, to provide scientific basis for controlling the pollution and the rational use of the novel fungicide picoxystrobin on cucumber. A method for determination of the residual amount of picoxystrobin in cucumber by using QuEChERS method and liquid chromatography was established. The average recoveries at fortified levels of 0. 02 mg/kg,0. 2 mg/kg and 1 mg/kg ranged from 76. 5% to 93. 4% with RSD less than 10%,indicating that the accuracy and precision were suitable for the requirements of pesticide residues testing standards in China. Picoxystrobin in cucumber dissipated quickly in one day after application, then gradually slow, and the residue concentration of picoxystrobin in cucumber at three days after treatment was lower than the MRL of EU (0. 05 mg/kg). The median residue(0. 508 mg/kg) of picoxystrobin in cucumber was lower than their mean value(0. 639 mg/kg). No obvious correlation between the weight of individual cucumber and the residue level of picoxystrobin was observed.