Preparation Of PANI/HAP/NF Composite And Research On Non-enzymatic Glucose Sensing

Glucose sensor can be divided into enzyme glucose sensor and enzyme-free glucose sensor.Glucose enzyme sensors rely heavily on the enzyme activity which limits its applications.Meanwhile,electro-catalytic oxidation of glucose at an enzyme-free electrode can avoid the disadvantages of glucose enzyme sensors.In recent years,the research on enzyme-free glucose biosensor has become a hotspot in related fields.Nickel foam(NF)has the characteristics of high porosity and low density,therefore can provide more active sites for electrochemical reaction.However,the biocompatibility and chemical stability of NF are not satisfactory and can not be directly used in biosensing.Hydroxyapatite(HAP)has good biocompatibility and biological activity,can be used for adsorbing and accumulating glucose molecules from solution.When the surface is conductivly modified,it can be used for electrochemical detection of glucose.In this thesis,NF electrode was used as the matrix material for preparing a composite electrode,and hydroxyapatite was deposited on NF surface by a cathodic electrochemical deposition.The prepared HAP/NF electrode then was characterized by some experimental methods,such as SEM,EDS,XRD and FT-IR.Based on the above results,PANI was deposited on HAP/NF surface by chemical in situ polymerization,and the PANI/HAP/NF electrode was also characterized by the same methods.The electrochemical properties of PANI/HAP/NF electrodes in NaOH solution were investigated by cyclic voltammetry(CV).Meanwhile,CV and i-t curves were used to study the electrochemical catalytic effect of PANI/HAP/NF electrode on the electrochemical oxidation of glucose oxidation in the mixtures of 0.10 mol/L NaOH and glucose with different concentration,as well as the selectivity,stability and reproducibility in glucose detection.The results show that HAP deposited on the NF surface is short rod.Aniline is polymerized on the surface of HAP/NF electrode successfully and formed PANI fiber.The PANI/HAP/NF electrode exhibits a good electrochemical activity in the mixtures of glucose and NaOH.The linear concentration range of the enzyme-free glucose sensor assembled with PANI/HAP/NF is divided into three sections,ranged from 0.001 to 0.10 mmol/L,0.010 to 20.0 mmol/L and 20.0 to 30.0 mmol/L.The sensitivity are 1632.06 ?A/(mM cm2),94.00 ?A/(mM cm2)and 20.56?A/(mM cm2),respectively.The detection limit is 0.36 ?mol/L(S/N=3).The response current of the sensor to ascorbic acid and uric acid is only 4%of the glucose response current.In addition,PANI/HAP/NF electrode exhibits an excellent stability and reproducibility in glucose detecting.