Development of An Electrochemical Aptasensor Basic on the ssDNA Aptamer of Ractopamine

Abstract

Ractopamine was illegally used in stock farming widely. The ractopamine residues in animal tissues had a potential risk to human beings. Therefore,a sensitive and selective analytical method was developed for determination and monitoring of ractopamine. In this paper,a single-stranded DNA aptamer which could bind actopamine with high affinity was obtained by Isothermal Titration Calorimetry method. With this aptamer as a bio-recognizer,an electrochemical biosensor of detecting ractopamine was developed successfully. According to the differential pulse voltammetry analysis,a linear relationship was observed between the peak current value( ΔIp) and the log concentration of ractopamine ranging from 0. 5 ng/ml to 1. 0 ×102ng / ml,and the correlation coefficient was 0. 977 0. The detection limit was 0. 1 ng / ml with a reaction time of 15 min. Ractopamine with a same concentration was detected 7 times and the RSD was 3. 8%,it indicates the aptasensor have a good reproducibility. What'more,the aptasensor have a good specificity to RAC.