Research For Preparation And Application Of Sensing Electrode Based On Silicon Modified By P-hydroxy Phenyl Acid Polymer/Platinum

In recent years,electrodes modified by organic molecule polymer is calling a hotspot in chemical sensor research.With covalent grafting in organic molecules on the surface of the electrode,layer can form stable,high quality hybrid connection and the traditional electrode materials will be given more new sensing function.P-hydroxy benzoic acid has an oxidation reactive functional groups of carboxyl and a reducing functional hydroxy,and therefore have higher oxidation reduction activity.It can be modified on the electrode material surface to increase the chemical activity of the electrode,so as to realize the recognition of electrode to some substances.In this paper,with the mature technology of cyclic voltammetry in electrochemical,poly p-hydroxy benzoic acid(PHBA)is electrodeposited on Pt/n-n+-Si electrode surface.The PHBA/Pt/Si and PHBA/Cu HCF/Si photoelectric sensing electrode is obtained.Without reference electrode,we studied the respectively photoelectric response of catechol(CC)and small biological molecules of hydrogen peroxide(H2O2)on this two kinds of electrodes.Significance of the progress of the preparation of the electrode is application of PHBA in electrochemical sensing for the realization of the benzodiazepines and hydrogen peroxide sensor miniaturization to provide reference.The research of this paper includes the following two parts: 1.Preparation of PHBA/Pt/Si electrode and photoelectric response for CCWith the mature technology of cyclic voltammograms(CV),p-hydroxy benzoic acid is electrodeposited on the n-n+-Si silicon electrode,which is prepared by evaporating aluminum and platinum thin film in vacuum.PHBA/Pt/Si electrode is prepared.The difference of electrodes,surface have been compared from the scanning electron micrographs of PHBA/Pt/Si and Pt/Si electrode.Photoelectric responses of CC from the electrode are studied by CV and chronoamperometry.The experimental results show that CC can be detected by PHBA/Pt/Si electrode with quick response and a good linear relationship under illumination conditions.The linear concentration range of CC is 2×10 – 5 M-3.4×10-4 M,without applied voltage.The detection limit is 2 ?M(S/N = 3).But PHBA/Pt/Si electrode also has some degree of response to hydroquinone(HQ).2.PHBA/CuHCF/Si electrode preparation and photoelectric detection of H2O2In this part of the experiment,PHBA and cupric hexacyanoferrate(Cu HCF)is electrodeposited on the Pt/Si electrode to form PHBA/CuHCF/Si electrode.The surface morphology of the electrode is characterized with the SEM.The current response of H2O2 on the electrode has been studied.Results show that PHBA/CuHCF/Si electrodes still show well for detection of H2O2.Glucose,uric acid(UA),urea,and L–cysteine not interfer the detection of H2O2.The photoelectric response of H2O2 on PHBA/CuHCF/Si electrodes is rapid,high sensitivity,good linear concentration between 4.0×10-6M and 3.6 x 10-4M.