Attomolar Determination of Coumaphos by Electrochemical Displacement Immunoassay Coupled with Oligonucleotide Sensing

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• 作者：Zong Dai ; Hui Liu ; Yudong Shen ; Xingpeng Su ; Zhenlin Xu ; Yuanming Sun ; Xiaoyong Zou
• 刊名：Analytical Chemistry
• 出版年：2012
• 出版时间：October 2, 2012
• 年：2012
• 卷：84
• 期：19
• 页码：8157-8163
• 全文大小：303K
• 年卷期：v.84,no.19(October 2, 2012)
• ISSN：1520-6882

文摘

Coumaphos, an organophosphorus pesticide (OP) used worldwide, has raised serious public concerns due to its positive association with major types of cancer. Herein, a novel method for attomolar coumaphos detection was developed on the basis of an electrochemical displacement immunoassay coupled with oligonucleotide sensing. An optimized displacement immunoassay was constructed to improve the binding efficiency of an antigen鈥揳ntibody pair, and a guanine-rich single-strand DNA label, in combination with oligonucleotide sensing, was used to amplify the detection signal with 鈥渄irect鈥?relationship to the analyte. As a result, coumaphos was sensitively determined from the enhanced catalytic cycle of guanine-Ru(bpy)₃²⁺ by chronoamperometry. The limit of detection (LOD) was down to 0.18 ng L^鈥? (S/N = 3), which is equal to 49.6 amol in a sample solution of 100 渭L. In comparison with conventional methods, the proposed method has the lowest LOD and better accessibility to high-throughput sensing systems. Besides, it can complete the whole analysis process in under 50 min and exhibits good performance of excellent selectivity to the OPs. With regard to the advantages of rapidity, convenience, low cost, and ease of operation, the proposed method has provided a promising platform capable of fast and in-field OP detection, which may make the system promising for potential applications in the detection of other small molecules.