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

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...

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Bibliographic Details
Published in:Analytical chemistry (Washington) 2012-10, Vol.84 (19), p.8157-8163
Main Authors: Dai, Zong, Liu, Hui, Shen, Yudong, Su, Xingpeng, Xu, Zhenlin, Sun, Yuanming, Zou, Xiaoyong
Format: Article
Language:English
Subjects:
Analytical chemistry
Cancer
Chemistry
Coumaphos - analysis
Deoxyribonucleic acid
DNA
Electrochemical methods
Electrochemical Techniques
Exact sciences and technology
Immunoassay
Miscellaneous
Molecules
Oligonucleotides - chemistry
Pesticides
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Summary: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–antibody pair, and a guanine-rich single-strand DNA label, in combination with oligonucleotide sensing, was used to amplify the detection signal with “direct” relationship to the analyte. As a result, coumaphos was sensitively determined from the enhanced catalytic cycle of guanine-Ru(bpy)3 2+ by chronoamperometry. The limit of detection (LOD) was down to 0.18 ng L–1 (S/N = 3), which is equal to 49.6 amol in a sample solution of 100 μL. 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.
ISSN:0003-2700
1520-6882
DOI:10.1021/ac301217s