Boron-doped Graphene quantum dots modified electrode for electrochemistry and electrocatalysis of hemoglobin

In this paper boron-doped graphene quantum dots (B-GQDs) decorated carbon ionic liquid electrode (CILE) was fabricated for the immobilization of hemoglobin (Hb), which was used as the electrochemical biosensor for electrocatalysis. Spectroscopic results demonstrated that the original structure of Hb was unchanged after mixed with B-GQDs, indicating the biocompatibility of B-GQDs. Electrochemical behaviors of Nafion/Hb/B-GQDs/CILE were investigated in pH 4.0 phosphate buffer solution and a couple of well-distinct symmetric redox peaks appeared on cyclic voltammograms. The results were also compared with GQDs and nitrogen-doped GQDs modified electrodes, which illustrated the enhanced effects of B-GQDs to electron communication and loading capability of Hb on the electrode surface due to its high conductivity and small size. Electrochemical kinetics were studied with the electrochemical parameters calculated. Electrocatalysis of Hb and B-GQDs modified electrode to various substrates such as trichloroacetic acid, sodium nitrite and hydrogen peroxide were carefully investigated. This new Hb modified electrode exhibited the advantages of large linear relationship, high sensitivity, low detection limit, good anti-interference ability and excellent stability, which found wide applications in food and drug samples detection.