PBA-MoS2 nanoboxes with enhanced peroxidase activity for constructing a colorimetric sensor array for reducing substances containing the catechol structure

Abstract

Some nanoperoxidase-based colorimetric sensors have been used to detect only one molecule at a time. Thus, the simultaneous detection of various molecules coexisting in the same system is a great challenge. In this work, an excellent nanoperoxidase, nickel cobalt Prussian blue analogue-MoS₂ nanoboxes (PBA-MoS₂), have been successfully prepared by the hydrothermal method and used to construct a colorimetric sensing array to determine a series of reductive substances containing the catechol structure (such as catechol, epinephrine hydrochloride, procyanidin, caffeic acid and dopamine hydrochloride). The excellent peroxidase-like activity of PBA-MoS₂ is verified by the chromogenic reaction of 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H₂O₂ in 2 min. The catalytic mechanism of PBA-MoS₂ is attributed to generated reactive species including holes (h⁺) and superoxide radicals (˙O₂⁻) in the process of catalysis. The fast economic H₂O₂ colorimetric sensing array has been constructed based on the PBA-MoS₂ nanoperoxidase. Due to the presence of different reducing substances, the catalytic oxidation of TMB can be restricted to different extents, accompanied by blue colour changes to varying degrees. Therefore, on combining PBA-MoS₂ nanoperoxidase with H₂O₂ and TMB, five reductive substances can be quantitatively distinguished by linear discriminant analysis (LDA) at the 2 mM level.