▎ 摘　　要

In this work, we reported on the electrochemical behaviors and electrocatalysis of myoglobin (Mb) biosensor based on SnO2 quantum dots functionalized three-dimensional graphene composite (SnO(2)QDs@3DGR) modified carbon ionic liquid electrode (CILE). The SnO2-QDs@3DGR composite was synthesized via a facile one-step hydrothermal strategy, which offered rich channels, enough active sites, high conductivity and good biocompatibility for bonding with Mb. The direct electron transfer (DET) performance between Mb and SnO2-QDs@3DGR modified electrode was greatly improved with electrochemical responses increased. In cyclic voltammetric investigation, a pair of well-defined redox peaks of Mb were observed with the formal peak potential of -0.263 V (C) and a peak-to -peak separation of 75 mV (AEp). The heterogeneous electron transfer constant (ks) was calculated as 1.34 s(-1). Furthermore, the modified electrode with chitosan (CTS) film (CTS/Mb/SnO2-QDs@3DGR/CILE) was used for the electrocatalysis of trichloroacetic acid, which showed a wider linear response from 5.0 to 94.0 mmol L-1 with the limit of detection as 0.35 mmol L-1.