Preparation Of Sulfonic Acid Polymer Modified Electrode And Its Application In Biological Analysis

Epinephrine?EP?is one of the important catecholamine neurotransmitters that play an important role in the mammalian central nervous system.The change of its concentrations in body fluids can cause various diseases such as schizophrenia and parkinson's disease.Uric acid?UA?is the final product of purine metabolism in the human body.Variations in the concentrations of UA in the human body have been related to many diseases,such as adiabetes,nephropathy,gout and hypercalcuria.Nitrite?NO₂^-?is prone to produce carcinogenic nitrosamines and its excessive concentration level in human blood will result in methemoglobinemia.Therefore,it is very important to detect these biomolecules.To overcome these problems,a variety of materials have been coated on the electrode surface to prepare various modified electrodes,such as metal nanoparticles,graphene,conductive polymers and carbon nanotubes,etc.,and applied to determinations of these biomolecules.Due to numerous advantages,such as simple preparation methods,strong selective,good stability and the thickness of the electrode surface can be controlled,conductive polymers have aroused people's concern.This paper includes three aspects as followed:1.A poly?2-Naphthalenesulfonic acid??P2-NSA?film modified glassy carbon electrode?GCE??P2-NSA/GCE?was fabricated by using simple cyclic voltammetric?CV?.The results show that the polymerized 2-NSA modified GCE?P2-NSA/GCE?not only exhibits strong electro-catalytic activities toward oxidations of EP,UA and NO₂^-,but also can resolve the sluggish and overlapped voltammetric responses of EP,UA and NO₂^-into three strong and well-defined oxidation peaks by using both CV and DPV,which can be applied for the selective and simultaneous determinations of EP,UA and NO₂^-in a mixture.Under the optimum conditions,the linear dependences of DPV current responses are observed for EP,UA and NO₂^-in the concentration ranges of 5-200?mol L^-1,5-200?mol L^-11 and 10-400?mol L^-11 with the correlation coefficients of 0.9992,0.9945 and 0.9994,respectively.The detection limits are 0.20?mol L^-1,0.21?mol L^-11 and 0.52?mol L^-11 for EP,UA and NO₂^-,respectively?S/N=3?.The different electrochemical behaviors of EP,UA and NO₂^-at various scan rates indicate that the electrode reaction of EP and UA are adsorption-controlled processes,and NO₂^-is a diffusion-controlled process at P2-NSA/GCE.The application of P2-NSA/GCE is demonstrated by simultaneous determinations of EP,UA and NO₂^-concentrations in human urine and serum samples with satisfactory results.2.A poly?2-naphthalenesulfonic acid-co-4-amino-3-hydrazino-5-mercapto-1,2,4-triazol??P2-NSA-AHMT?film modified glassy carbon electrode?GCE??P2-NSA-AHMT/GCE?hasbeenfabricatedbyusingelectrochemical copolymerization of 2-naphthalenesulfonic acid?2-NSA?and 4-amino-3-hydrazino-5-mercapto-1,2,4-triazol?AHMT?.The results show that P2-NSA-AHMT/GCE can negatively shifted oxidation potentials,enhanced peak current responses,resolves the sluggish and overlapped voltammetric responses of EP,UA and NO₂^-into three strong and well-defined oxidation peaks,the peak potential separation(?E_pa)of EP-UA and UA-NO₂^-are 0.12 V and 0.48 V,respectively,indicating the good electro-catalytic response of P2-NSA-AHMT/GCE towards EP,UA and NO₂^-.Thus,the P2-NSA-AHMT/GCE can be used for the simultaneous determination of EP,UA and NO₂^-in their mixture.Under the optimum conditions,the linear dependences of DPV current responses are observed for EP,UA and NO₂^-in the concentration ranges of 0.5-120?mol L^-1,3-140?mol L^-11 and 8-300?mol L^-11 with the correlation coefficients of 0.9973,0.9988 and 0.9952,respectively.The detection limits are 0.12?mol L^-1,0.14?mol L^-11 and 0.38?mol L^-11 for EP,UA and NO₂^-,respectively?S/N=3?.Due to the good selectivety and sensitivity,the P2-NSA-AHMT/GCE film modified electrode had been applied for simultaneous determinations of EP,UA and NO₂^-concentrations in human urine and serum samples with satisfactory results.3.A poly?2-naphthalenesulfonic acid-co-2-methoxy amino-2-?2-amino thiazole?-4-acetic acid??P2-NSA-AMTA?film modified glassy carbon electrode?GCE??P2-NSA-AMTA/GCE?has been fabricated by using electrochemical copolymerizationof2-naphthalenesulfonicacid?2-NSA?and2-methoxy amino-2-?2-amino thiazole?-4-acetic acid?AMTA?.The results show that the modified electrode not only exhibits electrocatalytic effects toward electrochemical oxidations of EP,UA and NO₂^-,but also can resolve the sluggish and overlapped voltammetric responses of EP,UA and NO₂^-into three strong and well-defined oxidation peaks by using both CV and DPV,which can be applied for the selective and simultaneous determinations of EP,UA and NO₂^-in a mixture.The modified electrode exhibited high catalytic activities in 0.1 mol L^-11 PBS pH 7.0.Under the optimum conditions,the linear dependences of DPV current responses are observed for EP,UA and NO₂^-in the concentration ranges of 1-110?mol L^-1,2-140?mol L^-1and 10-180?mol L^-11 with the correlation coefficients of 0.9976,0.9963 and 0.9986,respectively.The detection limits are 0.07?mol L^-1,0.12?mol L^-11 and 0.35?mol L^-1for EP,UA and NO₂^-,respectively?S/N=3?.Due to the good reproducibility and stabilities,the P2-NSA-AMTA/GCE film modified electrode had been applied for simultaneous determinations of EP,UA and NO₂^-concentrations in human urine and serum samples with satisfactory results.