Highly sensitive colorimetric detection of the toxic metal cadmium in rice using the 3-(1H-Tetrazol-5-yl) aniline@AuNPs sensor

A very poisonous heavy metal Cd 2+ not only contaminates the living environment but also constitutes a serious menace to human health through water intake and food chains. Thus, monitoring and controlling the content of Cd 2+ with rapidity, sensitivity, and simplicity in tap water, soil, and rice samples is important especially. In the work, a high-efficiency sensor based on gold nanoparticles (AuNPs) embellished and refined with 3-(1H-Tetrazol-5-yl) aniline (TAA) for the colorimetric detection of Cd 2+ is rationally put forward. The interaction between Cd 2+ and TAA@AuNPs leads to the agglomeration of the AuNPs solutions, resulting in the color of the system changing from wine-red to gray-blue. The limit of detection (LOD) of the sensor is 1.0 μM when observe with the unaided eye, and UV–vis spectroscopy also has a LOD of 31 nM with an excellent linear relationship ( R 2  = 0.99049) in the concentration range of 0.0–8.0 μM for Cd 2+ , indicating that AuNPs modified with TAA can be effectively used for the quantitative determination of Cd 2+ . Furthermore, the colorimetric sensor has been tested on tap water, soil, and rice samples, and it shows promising potential for the practical monitoring of harmful Cd 2+ in environmental systems.