Rational design of vitamin B3 derived bimetallic doped Cu-MOF with laccase-like activity for the colorimetric detection of Cr3+

Given the potential risks posed by the toxic heavy metal ion Cr 3+ to environmental and human health, the development of fast, simple, and visible detection methods for Cr 3+ is critical to control its detrimental effects. This study presents a sensitive and selective colorimetric method for Cr 3+ analysis, leveraging the laccase-like activity of Co,Zn@Cu-MOF(V B3 ), which was synthesized via a microwave digestion approach. The usage and proportion of precursors (vitamin B3 and CuCl 2 ) were examined to obtain the material exhibiting the optimal catalytic activity and response to Cr 3+ . The well-designed Co,Zn@Cu-MOF(V B3 ) exhibited remarkable laccase-like activity at pH of 5.8, and can oxidize the colorless substrate (2,4-dichlorophenol) to red product with 4-aminoantipyrine as the chromogenic agent. The findings indicate that Cr 3+ induces a decrease in absorbance at 505 nm. Under optimal conditions, the absorbance was linearly proportional to the Cr 3+ concentration in the range of 0.68–679.25 ng/mL, achieving a detection limit of 0.124 ng/mL. The method also displays robust anti-interference performance against other metal ions, and was successfully applied in the determination of Cr 3+ in water samples, yielding recoveries ranging from 90.2 % to 108.8 %.