School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, P. R. China.
Anal Chem. 2012 Oct 2;84(19):8157-63. doi: 10.1021/ac301217s. Epub 2012 Sep 11.
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.
氯菊酯是一种在世界范围内使用的有机磷农药 (OP)，由于其与多种癌症的正相关关系，引起了公众的严重关注。在此，基于电化学置换免疫分析结合寡核苷酸传感，开发了一种检测氯菊酯的新方法。优化了置换免疫分析，以提高抗原-抗体对的结合效率，并结合寡核苷酸传感，使用富含鸟嘌呤的单链 DNA 标记物，以与分析物呈“直接”关系的方式放大检测信号。结果，通过计时安培法，氯菊酯可通过鸟嘌呤-Ru(bpy)(3)(2+)的增强催化循环进行灵敏测定。检测限 (LOD) 低至 0.18 ng L(-1) (S/N = 3)，相当于 100 μL 样品溶液中的 49.6 amol。与传统方法相比，该方法具有最低的 LOD 和更好的可及性，适用于高通量传感系统。此外，它可以在 50 分钟内完成整个分析过程，并表现出对 OPs 的出色选择性。由于具有快速、方便、低成本和易于操作的优点，该方法为快速和现场 OP 检测提供了一个有前景的平台，这可能使该系统有望在其他小分子的检测中得到应用。
