Preparation And Application Of Eleetrochemtical Biosensor Based On Ionic Liquid And Titanium Dioxide Nanocomposite

Due to the wide application in food analysis, medicine, life sciences and environmental chemistry, theelectrochemical biosensor has become one of the important research directions of modern analyticalchemistry. In this paper, ionic liquid and GNPs-TNTs were used as electrode modification materials toexploite the different characteristices between hydrophobic ionic liquid and hydrophilic ionic liquid in thedevelopment of two kinds of enzyme sensor with different immobilization methods.1. Preparation and characterization of GNPs modified TNTsIn our work, GNPs were immobilised on the TNTs using a one-step reduction of HAuCl4·3H2O bysodium borohydride in the presence of sodium citrate as a stabilizing reagent. The morphology andcomposition of the as-synthesised composite materials were characterized by transmission electronmicroscopy, scanning electron microscopy, X-ray diffraction and Fourier-transform infrared spectroscopy.2. The enzyme sensor based on hydrophobic ionic liquid|nanoparticle–dotted titanate nanotubescaffoldIn this work, a novel sensing scaffold, consisting of GNPs-TNTs as the rigid material and thehydrophobic ionic liquid （HoIL） as the entrapping agent, was immobilized on a glassy carbon electrode tofacilitate the electron transfer of horseradish peroxidase （HRP）. The modified electrode was applied tothe detection of H2O2in a pH7.0phosphate buffer using chronoamperometry. The biosensor exhibited alinear response in the15×10^-6—0.75×10^-3mol·L^-1range and a limit of detection of2.2×10^-6mol·L^-1.Thebiosensor also displayed stability with90%of the detection signal retained over a two-week duration.3. The enzyme sensor based on hydrophilic ionic liquid|nanoparticle–dotted titanatenanotube scaffoldAqueous solution of HRP was employed as a gelator to immobilize a composite scaffold consisting ofhydrophilic ionic liquid（HiIL）, HRP and GNPs-TNTs on the electrode surface for the first time. Thecomposite scaffold provided a biocompatible microenvironment for HRP to keep its bioactivity and obtaindirect electrochemistry. The biosensor responded to H2O2in the linear range from5×10^-6—1×10^-3mol·L^-1with a detection limit of2.1×10^-6mol·L^-1.