农药乳油中7种助剂的顶空气相色谱测定方法

以25%毒死蜱-阿维菌素乳油为研究对象,采用顶空气相色谱,对农药乳油中二氯甲烷、三氯甲烷、1,1,1-三氯乙烷、苯、1,2-二氯丙烷、四氯乙烯和1,1,2,2-四氯乙烷7种有害助剂含量的多组分同时测定方法进行了研究。样品于顶空瓶中用体积分数为20%的二甲基甲酰胺水溶液溶解,密封后上下翻转15次,室温下静置过夜,80 ℃水浴30 min后,取顶空气体进行测定。方法的线性 决定系数大于0.995 0,除四氯乙烯和1,1,2,2-四氯乙烷外,其他5种助剂的添加回收率在74.4%~ 102.8%之间,定量限(LOQ)为0.2~5.0 mg/L。采用所建立方法对5种市售农药乳油中7种助剂的含量进行了分析,有部分助剂被检出。

Analysis of seven adjuvants in emulsifiable concentrate with headspace gas chromatography

A method was investigated to determine the seven harmful adjuvants including dichloromethane,trichloromethane,1,1,1-trichloroethane,benzene,1,2-dichloropropane,tetrachloro-ethylene,1,1,2,2-tetrachloroethane in 25% chlorpyrifos-abamectin emulsifiable concentrate simul-taneously with headspace(HS) and gas chromatography-flame ionization detector(GC-FID).Except tetrachloroethylene and 1,1,2,2-tetrachloroethane,the method was valuable to analyze other 5 compounds.The sample was resolved with 20% DMF and sealed in HS vial,inverted for 15 times.After keeping in ambient temperature for overnight,the sample was put into water bath for 30 min at 80 ℃,then HS sample was analyzed with GC-FID.The linearity was well with the determination coefficient above of 0.995 0.Except tetrachloroethylene and 1,1,2,2-tetrachloroethane,the recoveries ranged from 74.4% to 102.8%.The limit of quantifications(LOQs) were 0.2-5.0 mg/L.Five emulsifiable concentrate products from the market were tested with the optimized method,and two adjuvants were detected.