▎ 摘　　要

A composite that consisted of SnO2 nanosheet, graphene (GR), ionic liquid (IL) and hemoglobin (Hb) was modified on carbon ionic liquid electrode (CILE). By using Nafion film for fixing, the modified electrode was named as Nafion/Hb-IL-GR-SnO2/CILE. Spectroscopic data indicated that Hb molecules kept native structure within the composite. Cyclic voltammetric data gave a pair of well-defined redox peak in 0.1 mol L-1 phosphate buffer solution, proving that direct electron transfer of Hb in the composite with CILE was realized. The result was due to synergistic effects of the materials used, which fastened the electron transfer rate. Nafion/Hb-IL-GR-SnO2/CILE had excellent electrocatalytic ability to the reduction of trichloroacetic acid in a linear concentration range from 2.0 to 11.0 mmol L-1 with a detection limit of 0.615 mmol L-1. The modified electrode was valuable for the preparation of a third-generation electrochemical biosensor.