Attomolar determination of coumaphos by electrochemical displacement immunoassay coupled with oligonucleotide sensing.

Abstract

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.

• Authors: Zong Dai, Hui Liu, Yudong Shen, Xingpeng Su, Zhenlin Xu, Yuanming Sun, Xiaoyong Zou
• Journal: Analytical chemistry (Anal Chem) Vol. 84 Issue 19 Pg. 8157-63 (Oct 02 2012) ISSN: 1520-6882 [Electronic] United States
• PMID: 22934793 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Oligonucleotides
• Coumaphos

Topics

• Coumaphos (analysis)
• Electrochemical Techniques
• Immunoassay
• Oligonucleotides (chemistry)