Facile colorimetric sensing strategy for rapid and highly selective detection of Fumonisin B1 in food using Ag(I)–3,3′,5,5′-tetramethylbenzidine catalytic system

Fumonisin B1 (FB1) is a secondary metabolite produced by Fusariums, which principally contaminates grains and their products, causing pathological and physiological toxicity to humans and animals. Herein, a convenient and rapid colorimetric strategy for FB1 detection was established based on the inhibition effect of FB1 on Ag(I)–3,3′,5,5′-tetramethylbenzidine (TMB) catalytic system. It was found that FB1 can hinder the generation of superoxide anions (O2·-) in the sensing solution, leading to a significant reduction of oxTMB production. Thus, the absorbance and color change of the solution are directly related to the concentration of FB1. Under optimal experimental conditions, there is a satisfactory sensitivity with a limit of detection (LOD) as low as 1.77 ng·mL−1. Moreover, such colorimetric strategy has outstanding selectivity, and can be used for the detection of FB1 residues in corn and infant rice flour, with a recovery rate of 90.15–109.74 %. Especially, the RGB values corresponding to chromogenic solutions with different FB1 contents can be easily recognized by a smartphone for qualitative and quantitative analysis of FB1. The colorimetric sensing strategy does not require the preparation of nanomaterial, providing a low-cost and promising analysis strategy for FB1 detection.