A new Ionic Liquid-Modified Silver/Multi-Walled Carbon Nanotubes Biosensor for Detection of Glucose in Honey Samples

In the context of potential applications in food field, a new glucose biosensor was constructed by combining the advantages of tropine-amino acid based ionic liquids (TABILs), glucose oxidase (GOx), silver nanoparticles and multi-walled carbon nanotubes (MWCNTs). The effect of various ILs on GOx and their intermolecular interactions were systematically discovered, and then the different modified electrodes were fabricated and evaluated. As the result, the TABIL formed by the cation of butyl substituted tropinol and anion of serine ([BuTr][Ser]) was found to be the most ideal; the [BuTr][Ser]/Ag/MWCNTs fabricated electrode exhibited the largest active area, which was 1.68 times larger than that of the bare electrode. After further optimization, the electrode was modified with 5 mg/mL of GOx to detect glucose in phosphate-buffered saline (PBS, pH = 7), at a working potential of −0.45 V and 25°C. The GOx coverage was 2.16×10⁻⁹ mol/cm², the electron transfer rate (ks) was 0.91 s⁻¹, and the Michaelis-Menten constant ( \({\text{K}}_{\text{m}}^{\text{app}}\) ${\text{K}}_{\text{m}}^{\text{app}}$ ) was 5.10 mM. The test results were satisfied for actual honey samples, indicating that it had the good performance for glucose detection in potential foods.