Nanozyme coating-gated multifunctional COF composite based dual-ratio enhanced dual-mode sensor for highly sensitive and reliable detection of organophosphorus pesticides in real samples

• Published in: Journal of hazardous materials 2024-12, Vol.480, p.135791, Article 135791
• Main Authors: Wen, Shao-Hua, Zhang, Hengyuan, Yu, Sha, Ma, Junping, Zhu, Jun-Jie, Zhou, Yuanzhen
• Format: Article
• Language: English
• Subjects: Acetylcholinesterase - chemistry; Acetylcholinesterase - metabolism; Complicated real samples; Electrochemical Techniques; Homogeneous electrochemical detection; Limit of Detection; Manganese Compounds - chemistry; Metal-Organic Frameworks - chemistry; Methylene Blue - chemistry; Multifunctional COF composite; Organophosphorus Compounds - analysis; Organophosphorus pesticides; Oxides - chemistry; Pesticides - analysis; Phenylenediamines - chemistry; Ratio sensor; Thiocholine - chemistry; Water Pollutants, Chemical - analysis
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2024.135791

The reliable detection of organophosphorus pesticides (OPs) in complex matrices remains an enormous challenge due to inevitable interference of sample matrices and testing factors. To address this issue, we designed a nanozyme-coated mesoporous COF with guest molecule loading, and successfully used it to construct a dual-ratio dual-mode sensor through target-regulated signal generation. The multifunctional COF-based composite (MB/COF@MnO2, MCM) featured high loading of methylene blue (MB), oxidase-like MnO2 coatings as gatekeepers, and specific recognition of thiocholine (TCh). TCh, a regulator produced from acetylcholinesterase (AChE)-catalyzed hydrolysis of acetylthiocholine, could decompose MnO2 coatings, triggering the release of abundant MB and oxidation of few o-phenylenediamine (OPD). OPs, strong inhibitors of AChE, could restrain TCh production and MnO2 decomposition, thereby controlling the release of less MB and oxidation of more OPD. This regulation boosted the dual-ratio dual-mode assay of OPs by using the released MB and oxidized OPD in the solution as testing signals, measured by both fluorescent and electrochemical methods. Experimental results demonstrated the sensitive detection of dichlorvos with LODs of 0.083 and 0.026 ng/mL via the fluorescent/electrochemical mode, respectively. This study represented a creative endeavor to develop dual-ratio dual-mode sensors for OPs detection in complex samples, offering high sensitivity, excellent selectivity, and good reliability. [Display omitted] •Multifunctional COF composite (MCM) was prepared through convenient assembly.•MCM composite probe could respond to thiocholine (TCh) for two signals generation.•Fluorescent/electrochemical dual-readout was achieved by OPs-switched TCh formation.•A dual-ratio enhanced dual-mode sensor was developed for sensitive OPs detection.•The dual-ratio dual-mode sensor showed high reliability in practical application.