Boron Nitride Nanosheet Modified Electrode: Preparation and Application to Direct Electrochemistry of Myoglobin

An ionic liquid modified carbon paste electrode (CILE) was prepared with 1-hexylpyridine hexafluorophosphate (HPPF6) and used as a substrate electrode. Then hexagonal boron nitride (BN) nanosheet, myoglobin (Mb) and Nafion were fixed on the electrode surface by coating method to get a new-style chemically modified electrode (Nafion/Mb/BN/CILE). The morphology and crystal phase of BN nanosheet were characterized by SEM, TEM and XRD. UV-Vis and FT-IR results showed that Mb retained its original conformation in the composite modified film. In phosphate buffer solutions (PBS) with pH 3.0, cyclic voltammetry (CV) was performed to investigate the direct electrochemical behaviour of Mb. A pair of quasi-reversible redox reaction peaks was obtained on the CV curve, proving that BN nanosheet had good biocompatibility and could accelerate electron transfer between Mb and electrode surface. Electrocatalytic reduction of trichloroacetic acid (TCA) was investigated, which was further applied to TCA detection. The catalytic reduction peak current at -0.355 V depended linearly on the TCA concentration in the range of 0.2 similar to 30.0 mmol/L with the equation of Ipc (mu A)=6.340 C (mmol/L)+0.305 (r=0.998), and the detection limit was 0.05 mmol/L (3 sigma).