Metal–oxygen clusters as peroxidase mimics for their multifarious applications in colorimetric sensors

Abstract

A metal–oxygen cluster (Fe₂₈) was certified to show inherent peroxidase-like performance, which could catalyze the oxidation of the peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) using H₂O₂ in aqueous solution for the first time. The compound Fe₂₈ as a peroxidase mimic displayed multi-functional applications in the detection of H₂O₂, glucose and dopamine. The TMB/Fe₂₈/H₂O₂ system supplied a simple colorimetric approach for the detection of H₂O₂ and glucose with good sensitivity and had a linear range from 2.62 × 10⁻⁵ mol L⁻¹ to 1.57 × 10⁻⁴ mol L⁻¹ and 3.92 × 10⁻⁶ mol L⁻¹ to 3.14 × 10⁻⁵ mol L⁻¹, respectively. Moreover, the Fe₂₈ cluster could detect dopamine without H₂O₂ with a linear range from 4.62 × 10⁻⁵ mol L⁻¹ to 4.16 × 10⁻⁴ mol L⁻¹. Moreover, the Fe₂₈ cluster was low-priced, easy to synthesize and extremely effective in a colorimetric assay, which could lead to new opportunities for the development and application of metal–oxygen clusters.