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Published on: September 17, 2017
Enzyme-free multicolor sensor for visual detection of malathion based on a bimetallic magnetic nanozyme-mediated gold
Yuanying Chen1, Tianran Lin1, Shuangshuang He1
1School of Chemistry and Pharmaceutical Sciences, Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), Guangxi Key Laboratory of Environmental Processes and Remediation in Ecologically Fragile Regions, Guangxi Normal University, Guilin 541004, People's Republic of China.
Abstract:
Malathion plays an important role in agricultural production, and the accurate detection of malathion residues is essential to ensure food safety. A novel enzyme-free sensing method was proposed by employing bimetallic magnetic nanozymes for both colorimetric quantification and multicolor semi-quantitative detection of malathion. The nanozyme exhibits peroxidase-like activity, catalyzing H2O2-mediated oxidation of 3,3',5,5'-Tetramethylbenzidine dihydrochloride (TMB). Malathion inhibits this activity via ZrOP coordination, reducing oxidized TMB (oxTMB) generation. Under acidic conditions, oxTMB is further converted to TMB2+, which etches gold nanorods, inducing aspect-ratio variations accompanied by distinct multicolor changes. This method demonstrates low detection limits of 0.68 ng/mL. It does not require biological enzymes and can semi-quantify the malathion concentration through color changes. Thus, it can achieve convenient and accurate quantitative analysis without instruments, meeting on-site detection requirements. This work contributes to food safety and the development of efficient and reliable methods for malathion detection.
