Rapid colorimetric determination of dopamine based on the inhibition of the peroxidase mimicking activity of platinum loaded CoSn(OH)6 nanocubes.

Abstract

Platinum nanoparticles were loaded on CoSn(OH)6 nanocubes via a co-precipitation method. The material (NCs) is shown to be a viable peroxidase mimic that catalyzes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by hydrogen peroxide (H2O2) to generate oxidized TMB (oxTMB) with absorption at 652nm. The formation of the blue color can be observed in <30s. Thus, a visual and colorimetric assay was worked out for H2O2. It has a detection limit as low as 4.4μM and works in the 5 to 200μM concentration range. The method was also used to detect dopamine (DA) which is found to inhibit the enzyme mimicking activity of the NCs. Hence, less blue color is formed in its presence. The respective DA assay has a linear response in the 5.0 to 60μM concentration range and a 0.76μM detection limit. Graphical abstractSchematic diagram of a visual colorimetric method for determination of H2O2 and dopamine (DA) with the aid of color change of 3,3',5,5'-tetramethylbenzidine (oxTMB), based on the peroxidase-like activity of Pt/CoSn(OH)6 nanocubes.