麦麸酯酶抑制法检测辛辣蔬菜假阳性消除的研究

利用酶抑制法可以快速检测蔬菜中的有机磷和氨基甲酸酯类农药残留,这两者能够抑制酯酶的活性,而辛辣蔬菜中含有影响酶活性的含硫化合物,容易导致检测结果出现假阳性。为了消除辛辣蔬菜造成的假阳性,以酶活性抑制率为指标,采用不同的加热方式、时间对4种辛辣蔬菜进行前处理。结果表明,对样品提取液使用水浴加热可起到消除假阳性的作用,其中香葱、洋葱、大蒜和青椒的最佳水浴加热温度分别为80、90、80、80℃,经过处理后的样品提取液对麦麸酯酶的抑制率分别由原来的37.06%、9.65%、17.02%、50.34%下降到12.69%、2.95%、5.79%、33.61%。除青椒外,该方法可在一定程度上消除或大大降低植物酯酶抑制法中假阳性的影响,且不会造成农药残留的损失,从而提高酶抑制法对辛辣蔬菜快速检测的准确性。

Elimination of false positive in the detection of spicy vegetables by wheat bran esterase-inhibition method

The enzyme inhibition method can be used to quickly detect organophosphate and carbamate pesticide residues,which inhibit the activity of esterase.But spicy vegetables also contain sulfur compounds that affect enzyme activity,which can lead to false positives.In this experiment,using activity inhibition rate as the index,different heating treatment and time to deal with 4 kinds of spicy vegetables were carried out to eliminate or reduce the false positive in enzyme inhibition method.The results indicated that under the appropriate heating temperature,which was 80℃,90℃,80℃,80℃,for chives,onion,garlic and green pepper,respectively,the inhibition rate of enzyme activity decreased from 37.06%,9.65%,17.02%,50.34%to 12.69%,2.95%,5.79%,33.61%,respectively.In addition to green pepper,to some extent,this method could eliminate or greatly reduce the false positive that brought by spicy vegetables in the enzyme-inhibition method,which could improve the accuracy in enzyme-inhibition method to detect organophosphate and carbamate pesticide residues in spicy vegetables.