Study On The Preparation And Performance Of Ascorbic Acid Electrochemical Sensors

Ascorbic acid（AA）is an essential component of the body,and accurate detection of AA is of great importance in our daily life.The ascorbic acid electrochemical sensors have attracted more and more attention.However,other substances such as dopamine and uric acid also co-exist in the body,and their oxidation potential are almost same as ascorbic acid.Hence,the selectivity of ascorbic acid electrochemical sensor can be enhanced through the improvement of electrode materials and electrode modification methods.In this study,three non-enzymatic ascorbic sensors were fabricated by using polyimide（PI）,molybdenite（MLN）,and stretchable carbon nanotubes（SCNT）.The performances of these AA-based electrochemical sensors were investigated by both morphology and electrochemical behaviors.1.The methylene blue（MB）/PI/GCE sensor was prepared by physical adsorption of the mixture of MB and PI.The surface morphology was characterized by AMICS,LCHSM,and AFM.The sensor performance was evaluated by electrochemical methods.The MB/PI/GCE sensor has good stability and specific selectivity.The linear range of the sensor to detect AA is 3.0×10^-6-3.0×10^-3 M,with a detection limit（S/N=3）of 1.05μM.Due to the adhesion and insolubility of PI,MB was successfully immobilized on the GCE surface.The synergistic effect of PI and MB improved the catalytic activity of the electrochemical sensor.2.The natural molybdenite（MLN）based composite was prepared by MLN and copper nanoparticles through molten salt method,and the composite was characterized by SEM and XRD.The composite is 10-2000 nm long and 5-1500 nm wide,which has a larger surface area than the natural MLN.The MLN/Cu/GCE has a linear response current toward AA concentration in the range of 3×10^-6-3.0×10^-3 M.The detection limit（S/N=3）is 0.21μM.Furthermore,the sensor has good specificity,repeatability,and stability.3.Stretchable carbon nanotube（SCNT）was immersed in ferrocene-methanol（Fc-OH）solution to fabricate AA based electrochemical sensor.The SCNT/Fc-OH electrode was characterized by SEM to evaluate the surface structure.The linear range of AA is 3.0×10^-6-3.0×10^-3 M,and the detection limit（S/N=3）was 16.32μM.The sensor was also able to avoid the interference of common substances and had good stability.Finally,in this research,polyimide,molybdenite and stretchable carbon nanotubes were used as the basic materials for the preparation of ascorbic acid electrochemical sensors.The three kinds of AA electrochemical sensors have excellent electrochemical performance.This research not only provides new substrate materials for ascorbic acid electrochemical sensor,but also provides new applications for these three materials.