摘要:
本研究的目的是建立一种增强的酶抑制法,实现对谷物中有机磷农药残留的快速检测。通过对酶抑制法中所使用的提取剂、酶、增强剂的选择和优化,并比对抑制率的差异,最终确定使用丁酰胆碱酯酶作为催化酶、乙醇作为提取剂、溴代琥珀酰亚胺作为增强剂。在此条件下,建立了硫代磷酸脂类有机磷农药对硫磷、辛硫磷、毒死蜱和三唑磷的标准曲线(决定系数R2 > 0.98),抑制中浓度(IC50)分别为0.01、0.11、0.16和0.03 μg/L,满足了硫代磷酸酯类农药在不同谷物中的安全残留限量的检测需求。采用本研究改良的酶抑制法对200个不同来源的谷物样本(稻谷、小麦、玉米、糙米、杂粮)进行分析,检测出13个阳性样本,同时,因酶抑制法特异性的限制,产生了1个假阳性和1个假阴性样本。检测结果与气相色谱法符合率达到98%,表明该方法可有效用于谷物中有机磷农药残留检测。本研究可为我国粮食质量安全监管提供有力的技术支撑。
Abstract:
In this study,an enhancer-based enzyme inhibition method was established to achieve rapid detection of organophosphorus pesticide residues in cereals. The extractant,enzyme and enhancer used in the enzyme inhibition method were selected and optimized,by comparing the change of inhibition rate. Finally,butylcholinesterase was used as catalytic enzyme,ethanol selected as extractant,and bromosuccinimide as enhancer. Under these optimized conditions,the standard curves of parathion,phoxim,chlorpyrifos and triazophos were established(R2＞0.98). The IC50 values were 0.01,0.11,0.16 and 0.03 μg/L,respectively,which met the safety residue limits of this kind of pesticides. 200 grain samples(rice,wheat,maize,brown rice,miscellaneous grains)were tested using the improved enzyme inhibition method,in which 13 positive samples were detected,however,due to the specific limitation of the enzyme inhibition method,1 false positive samples and 1 false negative samples were generated. Results of exemplarily performedgas chromatography were well in accordance with measurements obtained by enzyme inhibition,and it was proved that the developed method could be used to detect the organophosphorus pesticide residue in the grain. This study can provide a powerful technical support for China grain quality safety supervision.
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