A peroxidase-like nanoenzyme based on strontium(II)-ion-exchanged Prussian blue analogue derivative SrCoO3/Co3O4 nanospheres and carbon quantum dots for the colorimetric detection of tigecycline in river water

Abstract

In this work, for the first time, we derived a composite of perovskite oxide SrCoO3 and Co3O4 by annealing the Prussian blue analogue exchanged with strontium ions and modified with carbon quantum dots (CQDs). Its peroxidase-like catalytic activity was explored. The peroxidase-like activity was mainly evaluated by the rate of the chromogenic reaction. When H2O2 was present in the reaction system, the colorless substrate 3,3′,5,5′-tetramethylbenzidine (TMB) was oxidized into a blue product (oxTMB), and this was monitored by UV–vis absorption spectrum. Among them, the SrCoO3 and CQDs not only promoted the generation of superoxide anion radicals (O2−•) and electron-hole pairs (h+) in the reaction system, but also accelerated the electron transfer between the substrate TMB and H2O2. Therefore, the peroxidase-like catalytic activity of the reaction system was significantly improved. Moreover, the complexation of tigecycline (TGC) and CQDs@SrCoO3/Co3O4 composite enhanced the peroxidase-like catalytic activity of the reaction system. Based on this, using TGC and TMB as template molecules, a molecularly imprinted colorimetric sensor for detecting TGC was constructed. The absorbance difference of the reaction system was linear with the TGC concentration in the range of 0.02–6.0 μM, and the detection limit was 4.46 nM. Furthermore, the proposed sensor had high selectivity and applied to the detection of TGC in Pearl River water.