Colorimetric detection of chromium (VI) ion using poly(N-phenylglycine) nanoparticles acting as a peroxidase mimetic catalyst

This paper reports on enzyme-like catalytic properties of polyethylene glycol-functionalized poly(N-phenylglycine) (PNPG-PEG) nanoparticles, which have not been explored to date. The developed nanoparticles the ability display great inherent peroxidase-like activity at very low concentrations, and are able catalyze oxidation 3,3′,5,5′-tetramethylbenzidine (TMB) substrate in presence hydrogen peroxide (H2O2). oxidized product TMB has a deep blue color with maximum absorbance ~655 nm. PNPG-PEG exhibit Km values 0.2828 for 0.0799 H2O2, indicating that takes place lower concentration H2O2 comparison other nanozymes. Based known mechanism by hexavalent chromium [Cr(VI)] ions generate hydroxyl radicals (•OH), these were successfully applied colorimetric sensing Cr(VI) ions. sensor achieved good performance detection limits 0.012 μM (0.01–0.1 linear range) 0.52 (0.05–12.5 range). scheme was highly selective, real water samples.