The Application Of Modified Carbon Paste Electrode In Biologic Trace Elements Analysis

Electrochemical analysis was a sensitive method for determination of trace elements in biologic samples. Electrochemical analysis especially cyclic voltammetry could be applied in studying biologic samples, determination of electrochemical activity components. Biological messages could be studied uniquely basing on the electron transmission characteristics of between electrochemical activity components and electrode surface.The electrochemical behavior of selenocystine(SeC) and selenomethine(SeMet) were studied by cyclic voltammetry, chronocoulometry based on silver nitrate modified carbon paste electrode (AgNO₃/CPE). The result suggested SeC and SeMet had the similar voltammetric behavior at AgNO₃CPE electrode and they both catalyzed the electrochemical reduction of Ag. In addition, their electrochemical reaction mechanisms were investigated, and the electrochemical processes of them with Ag were one-electron reaction yielding complex Ag⁺SeC.An ethylenediaminetetraacetic acid (EDTA) modified carbon electrode was constructed by electric potential analysis in the determination of Cu²+. A linear potential response for the concentration of Cu²+ in the range of 1.0 x l0^-3 1.0xl0^-8mol/L was observed at this modified electrode in the B-R Buffer Aqua(pH=3.29). The detection limit was found to be 1.0xl0^-8mol/L. From measuring selectivity coefficient of the seven interference ions(Pb²+,Zn²+,Cd²+,Ni²+,Fe³+,Ca²+, Mg²+)in Cu²+ Aqua, and apply to the measuring of actual samples. So we can get a measuring method which is new, convenient, agility and no poisonous.