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

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.