Film Chemically Modified Electrode Research And Application

Abstracts: The chemically-modified electrodes (CME) have been a most burgueoning and of the most flourish research realms in the electrochemistry and electroanalytic chemistry. It was for the moment widely appied in many case such as life sicence, envioronment sicence, energy source sicence, analytic sicence, electronics and meterial science. The film chemicaly modified electrodes are prepared by desigining the electrodes surface on the molecule level and immobilizing the molecules, ion and polymers of the specifically chemical and electrochemical functions. The mediator modified on the surface of electrode can accomplish the electrocatalytic reactions by accelerating electron transferring between redox centers and electrode surface. The eletrocatalysis of the modified electrode is an enormous impetus for its development and is widely used in the slow electron transferring processes, which isn't easily realized, such as the electroanalysis of biomolecules, orgnic compounds and inognic ions. With specially chemical and electrochemical functions the modified electrode enriched the electrode materials and expanded the reseach fields of the electrochemistry.The preparations of the polymer films are very simple. The polymer film modified electrodes also have many other choiceness characters which have been widely synthesized; the polymer films usually have chemical, mechanical and electrochemical stability; the thickness of the film can be changed. So the polymer film modified electrode have very good development foreground on the application or research. Self-assembly as a new technique for the application of orgnic ultitrafilm was applied in various research fields by more and more investigations. Self-assembled monolayer (SAMS) is a kind of single molecular layer which deposited on the surface of the monolayer is that the molecules in the monolayer haxe a common direction, which is the molecules are well organized and oriented. It's well know that calixarenes are a good group of cavity-shaped cyclic molecules comprising phonel units linked via alkylidene group. They process special cavity structure and thus are able to form host-guest inclusion complexes with a variety of molecules selectivity, if calixarenes weremodified on the electrode to form chemically membrance-modified electrodes, some molecules with electrochemical characters may be separated each other.In our papers, we made several modified electrodes with special functions by electrochemically polymerization, we also reseach the functions of these electrodes, such as the ability of electroanalyse, slection and adsorption. At the same time we use these modified electrode to determine the real products. The whole paper includes five parts,First, A new chemically modified GC electrode has been prepared by using polymeric L-giutamic acid/Fe (CN)₆^3- as a modifier. The best conditons of preparation and usation were studied. The result of the experiment shows that the midified electrode exerts an apparent catalytic effect on the cadmium (â…¡) oxidation. The stripping peak of cadmium (â…¡) ion on polymeric L-glutamic acid/Fe(CN)₆^3-/GC is proportional to concentration of cadmium(â…¡) ion between 4.0×10^-9～3.0×10^-5molL^-1. The detection limit is 2.5×10^-9molL^-1. The modified electrode was used to measure cadmium in water sample.Second, A new chemically modified GC electrode was prepared by using poly-L-histidine/Fe (CN)₆^3- as a modifier. The best conditions of preparation and usation were studied. The results of the experiment show that the modified electrode exerts an apparent catalytic effect on the silver (â… ) ion. The oxidation stripping peak current increases linearly With the concentration of silver ion between 1.0×10^-12～5.0×10^-6molL^-1.The detection limit is 1.0×10^-13molL^-1. The modified electrode can be used to measure silver (I) ion in water.Third, A new Chemically modified glass carbon electrode has been prepared by using polyglycine/Fe(CN)₆^3- as a modifier, the electrochemical behaviors of lead (â…¡) ion on the modified electrode have been studied. A new approach is developed for sensitive and accurate determination of lead by the electrode. The stripping peak of lead (â…¡) ion on Polyglycine /Fe (CN)₆^3-/GC is proportional to concentration of lead (â…¡) ion between 1.0¹0^-9～7.0×10^-6molL^-1 and detection limit is 8.6x10^-10molL^-1.Forth, A new chemically modified GC electrode has been prepared by using polymeric L-phenylalanine acid/Fe(CN)₆^3- as a modifier, the electrochemical behaviors of Ascorbic acid (Vc) on the modified electrode have been studied. A new approach is developed for sensitive and accurate determination of Vc by the electrode. The peak of Vc on polymeric L-phenylalanine acid/Fe(CN)₆^3-/GC is proportional to concentration of Vc between 4.0×10^-7～2.0×10^-2molL^-1. The detection limit is 2.4×10^-7molL^-1. The modified electrode has been used to measure the effective content in pills of VcFifth, A polyhistidine-Ni film modified electrode has been prepared at bare GC, and its electrochemical behavior was studied by cyclic voltammetry. The experiments confirmed the electrochemical catalytic oxidation of formaldehyde on the modified electrode. Over the rang 5.0×10^-7～, 2.0×10^-5molL^-1, the oxidation peak currents are linearly proportional to the concentration of formaldehyde, the detection limit is 2.3×10^-8moiL^-1. The modified electrode can be used to measure formaldehyde in aqueous solution.