Oxidative properties and utility of fabricated MnSiO 3 nanoparticles for colorimetric detection of iron (II) in water samples

MnSiO 3 nanoparticles (NPs) were prepared by precipitation method, their structure and composition were characterised by transmission electron microscopy, electron diffraction spectroscopy, X‐ray diffraction, and X‐ray photoelectron spectroscopy. Due to the oxidase‐like enzyme activity of MnSiO 3 , it can catalyse the substrate 3,3′,5,5′‐tetramethylbenzidine (TMB) in acidic environment to form an oxidised TMB which has an absorption peak at 652 nm in the absence of hydrogen peroxide. When Fe 2+ was added to the assay, the oxidase‐like activity of MnSiO 3 was inhibited, and the intensity of the absorption at 652 nm was reduced. Based on the high oxidase‐like activity, a colorimetric method for Fe 2+ detection was established, it showed high selectivity and sensitivity. In the optimised conditions, the limit of detection was 0.5 μM with a linear range from 3 to 63 μM. Moreover, the method was applied to determine Fe 2+ in spiked water samples which gave satisfactory recoveries.