BSA-stabilized silver nanoclusters for efficient photoresponsive colorimetric detection of chromium(VI)

Hexavalent chromium is a highly toxic substance, which will pose a serious threat to human life and health and the entire ecosystem. Therefore, it is crucial to establish a simple and rapid detection method for hexavalent chromium. In this work, we fabricated bovine serum albumin-stabilized silver nanocluster (BSA-Ag-13 NC) which exhibited photoresponsive oxidase-like activity, catalyzing the oxidation of colorless 3,3 ',5,5 '-tetramethylbenzidine (TMB) to the blue oxidized state TMB (oxTMB) in a short time. Interestingly, 8-hydroxyquinoline (8-HQ) can significantly inhibit the color reaction of TMB oxidation while Cr(VI) can interact specifically with 8-HQ to restore this chromogenic reaction. Based on the above facts, a colorimetric sensing system for detecting Cr(VI) was developed. The sensing system shows a wide linear range, and good selectivity, with a low detection limit of 2.32 nM. Moreover, this sensing system could be successfully applied to the detection of Cr(VI) in lake water, tap water, and sewage with satisfactory results.

Automated summary

In this study, bovine serum albumin-stabilized silver nanoclusters (BSA-Ag-13 NC) were fabricated to catalyze the oxidation reaction of colorless 3,3',5,5'-tetramethylbenzidine (TMB) to the blue oxidized state TMB (oxTMB), enabling the rapid detection of hexavalent chromium. A colorimetric sensing system for detecting Cr(VI) was developed based on the specific interaction between 8-hydroxyquinoline (8-HQ) and Cr(VI) to restore the color reaction of TMB oxidation. The sensing system showed a wide linear range, good selectivity, and a low detection limit of 2.32 nM. Moreover, it successfully detected Cr(VI) in lake water, tap water, and sewage with satisfactory results.