The Fabrication And Application Of Pre-anodized Interlay Ultrathin Carbon Paste316L Electrode

Chemically modified carbon paste electrode has attracted extensive attention in the fieldsof electrochemical and electroanalytical chemistry, etc. The construction of new kinds ofchemically modified carbon paste electrode can expends their application in electrochemical.In this thesis, the main performance of pre-anodized interlay ultrathin carbon paste316L(PAIUCP-316L) electrode and pre-anodized carbon paste electrode (PACPE) are asfollowing:1. Study on the impact of acidity and reduction reaction of platinum electrode on theoxidation peak currents of uric acid and guanine at PAIUCP-316L electrodeThe pre-anodized interlay ultrathin carbon paste316L (PAIUCP-316L) electrode wasprepared by matrix of316L stainless steel with the diameter of2.5mm and used to thesimultaneous determination of uric acid (UA) and guanine (G) in this paper. The impact of pHon oxidation peak currents was discussed on the basis of the distribution coefficient of UAand G for the first time, according to the relation curves of Ip-pH and Ep-pH of two analytes.Results showed that variety abilities to lose electrons on electrode surface of differentacid-base species of UA and G might be the important factor that the oxidation peak currentswere affected by the pH. Moreover, one of the possible reasons which leading to the oxidationpeak currents of UA and G at working electrode changed with the changing of pH might bethat the extent of reduction reaction of auxiliary electrode decreased with the increase of pHwas put forward for the first time. It also proposed that, due to the H+which was released inreaction layer by the oxidation of UA and G, the consumption of H+in cathode reaction couldbe supplemented by means of migration from reaction layer to cathode along a concentrationgradient, and this provided driving force for the migration of UA and G from diffusion layer towards reaction layer. The determination conditions such as pH, scan rate and species ofbuffer solutions were optimized and showed that when in PBS buffer solution(pH=5.00) withthe scan rate of0.1V·s-1, the oxidation peak currents of UA and G were linearly with theirincreasing concentrations in the range of5.0×10-7to2.2×10-4mol·L-1and2.0×10-7to1.5×10-4mol·L-1with the detection limit of8.2×10-8and3.4×10-8mol·L-1, respectively. This methodwas also used to detect the content of UA and G in healthy adult urine with satisfactoryresults.2. Simultaneous determination of folic acid and acetaminophen on316L-PAIUCPE andaffect by solution acidity and reaction extent of auxiliary electrodeA novel316L pre-anodized interlay ultrathin carbon paste electrode (316L-PAIUCPE)on the substrates of industry316L stainless steel was prepared for the first time in this paper.Setting folic acid (FA) and acetaminophen (AC) as analytes, the electrochemical properties ofthem on316L-PAIUCPE were studied, and the size of oxidation peak currents of AC and FAwhich affected by solution acidity and reaction extent of auxiliary electrode were discussed indetail. Results indicating that, AC and FA showed strong electrochemical signals on316L-PAIUCPE with the oxidation peak potentials of0.408V and0.727V. The oxidationpeak currents of AC and FA were linearly with their increasing concentrations in the range of5.0×10-7~2.0×10-4mol·L-1and2.0×10-7~2.2×10-4mol·L-1with the detection limit of7.0×10-8mol·L-1and2.1×10-8mol·L-1, respectively. This method can also be used to determine thecontent of AC and FA in tablets successfully.3. Study on the electrochemical behaviors of epinephrine on a pre-anodized carbon pasteelectrodeEpinephrine (EP) was used as a target molecule, a new method for the determination ofEP by a pre-anodized carbon paste electrode (PACPE) was established. The experimentalresults showed that the electrode had excellent electrochemical response to EP. In PBS buffer solution of pH=7.00, the peak current of EP was linear with its concentration in the range of2.0×10-7to1.0×10-4mol·L-1with the linear equation of Ip(A)=0.4598+0.1544c(mol·L-1),detection limit of2.9×10-8mol·L-1and the correlation coefficient of0.9981. This methodcould be used for the content determination of EP in injection.