基于DNA酶催化反应建立适配体比色法检测鸡蛋中氯霉素

An aptamer colorimetric method was established to detect chloramphenicol in eggs based on DNase-catalyzed reaction

目的:通过制备适配体—磁珠复合体,利用氯霉素的特异性结合可解离适配体与DNA酶的结合,并解除对该酶与血红素结合催化显色反应活性抑制的机理,建立用于快速检测鸡蛋中氯霉素的方法。方法:通过适配体与DNA酶碱基互补配对后,再将该结合体通过羧基和氨基的缩合反应,制备适配体—磁珠复合体。再通过加入不同浓度的氯霉素溶液以实现与其适配体的结合,使得DNA酶与氯霉素核酸适配体发生解离,被解离出的DNA酶与血红素结合催化显色反应。结果:该方法检测氯霉素的线性范围为0.001~100.000 mg/kg,其吸光度值与氯霉素浓度呈线性相关,在5,10,25 mg/kg 3种添加水平下该比色法的回收率为98.4%~101.1%,相对标准偏差均小于10%。结论:该方法通过引入DNA酶和磁性纳米粒子有效克服了传统快速检测方法的非特异性吸附引起的假阳性结果,适用于快速检测鸡蛋中氯霉素的残留量。

Objective:A new method for the rapid detection of chloramphenicol in eggs was established,by preparing the aptamer magnetic bead complex,based on the mechanism of inhibiting the catalytic color reaction between the DNase and heme.Methods:The aptamer and DNase was combined through complementary base pairing,and it was combined with aptamer composite magnetic beads.Furthernore,by adding different concentrations of chloramphenicol solution,the DNase and chloramphenicol nucleic acid adaptation was disintegrated by dissociation of DNase catalytic chromogenic reaction combined with hemoglobin.Results:The linear range of chloramphenicol was 0.001~100.000 mg/kg,and the absorbance was linearly correlated with the concentration of chloramphenicol.The recoveries of the colorimetric method were 98.4%~101.1%at 5,10,25 mg/kg,and the relative standard deviations were all less than 10%.Conclusion:By introducing DNASE and magnetic nanoparticles,this method can effectively overcome the false positive results caused by non-specific adsorption of traditional rapid detection methods,and is more suitable for rapid detection of chloramphenicol residues in eggs.