溶剂强度对农药残留回收率的影响

[目的]为了筛选出合适的过柱溶剂强度。[方法]将溶液中乙腈与水的比例设为60∶30、60∶20和60∶10,用C18小柱(1000mg,6ml)萃取黄瓜样品,采用气相色谱-质谱联用法测定76种农药在0.5mg/kg水平上的添加回收率。[结果]乙腈与水的比例为60∶10的处理在70%～120%、80%～110%和85%～105%的回收率区间内均有良好表现,其农药分布百分率分别为90.78%、80.26%和59.21%。乙腈与水的比例为60∶10处理的农药回收率明显优于60∶30和60∶20处理。[结论]固相萃取小柱的使用缩短了农药残留检测的前处理过程所需要的时间。过柱溶剂强度是影响农药回收率的关键因素。乙腈与水的比例为60∶10的溶剂强度是合适的过柱溶剂强度。

Effects of Solvent Strength on the Recovery of Pesticide Residue

[Objective] The study aimed to screen out the suitable solvent strength passing column. [Method] The ratios of acetonitrile to water in solutions were set at 60∶30, 60∶20 and 60∶10. The cucumber samples were extracted by C18 columella (1 000 mg, 6 ml). The recoveries of 76 pesticides at 0.5 mg/kg level were determined by GC-MS method. [Result] The treatment with ratio of acetonitrile to water being 60∶10 had good performance in the recovery intervals of 70%-120%, 80%-110% and 85%-105% and their distribution percentages of pesticides were 90.78%, 80.26% and 59.21% resp. The pesticide recovery in the treatment with ratio of acetonitrile to water being 60∶10 was significantly superior to that of 60∶30 and 60∶20. [Conclusion] The usage of solid phase extraction column shortened the time needed for pretreatment in pesticide residue detection. The solvent strength passing column was the key factor influencing pesticide recovery. The solvent strength with ratio of acetonitrile to water being 60∶10 was the suitable solvent strength passing column.