The Fabrication, Evaluation And Application Research Of Novel Sheet Carbon Electrode

Researches on the innovation of analytical methods have become more and more popularand also important. Researchers are working on the issues about how to reduce the relying onlarge-scale, expensive instruments in laboratory, how to reduce the steps of samplepretreatment, how to simplify the measurement, and all in all, how to cut the cost of analyticaltests. In this trend, the fabrication of variety micro sensors has become a hotspot, and theelectrochemical sensor is more attractive for its high sensitivity in analysis. Traditionalelectrochemical sensors have some disadvantages, such as its complex constitution and thelack of convinience in using. Nowadays, as the base tool of making a electrochemical sensor,a kind of sheet carbon electrode fabricated with screen-printed technique has caughtresearchers’ interests for its simple construction and ease of use. It is also namedscreen-printed electrode. In this thesis,3types of sheet carbon electrodes are fabricated withscreen printing method. As the study of the screen-printed electrode application, thecombinations of molecular imprinted technology and electrochemical analysis,electrogenerated chemiluminescence analysis are applied on the electrodes. The detailedcontents included:First of all，a kind of conductive carbon paste was fabricated using graphite powder asthe material, the mixture of cyclohexanone and1-methyl-2-pyrrolidone as the solvent,cellulose acetate as the adhesive. The addition of BPFP improves the conductivity of thecarbon paste.3types of screen-printed electrode were designed, and then made withscreen-printed technique. Comparative studies have been carried out on preparing conditionsand the storage of screen-printed electrodes. The electrochemical performance of theelectrode and the coherence of electrodes made in the same batch were also studied.Then, the applications of screen-printed electrodes in the preparation of molecularimprinting sensors were studied.In one of the studies, a high-selective dopamine imprinted sensor based onscreen-printed electrode has been developed through electromerization.M-aminophenylboronic acid was chosen to be the monomers, while dopamine was thetemplate molecular in the fabrication. Conditions of the experiment have been optimized then.The concentration rate of monomers and template molecular were1.2:1, the polymerizationpotential range was0-1.2V, the template molecular on the polymer film can be removed byscanning20cycles in0.5mol/L H2SO4in potential range of0~1.5V. The sensor owns thespecialty of good stability, high-sensitive, high-selective for dopamine. Under the optimalcondition, the linear range was2×10-6~1.4×10-5mol/L and the limit of detection (S/N=3)was1×10-6mol/L. In the other study, a nafion film doped with multi-walled carbon nanotubes wasdecorated on a screen-printed electrode. After that, a Ru(bpy)32+/Nafion/MWCNT modifiedelectrode was prepared with immobilizing Ru(bpy)2+3. In order to improve the selectivity, theelectrochemiluminescence-molecular imprinting sensor (ECL-MIP sensor) was fabricated onthe Ru(bpy)32+/Nafion/MWCNT modified electrode by gel-sol molecular imprinting (MIP)technologies. The scan rate, pH and incubation time were optimized. The sensor combined thesensitivity of electrochemiluminescence and selectivity of molecular imprinting. Under theoptimal condition, the linear range was1.0×10-10~1.0×10-13mol/L and the limit of detection(S/N=3) was1.0×10-14mol/L.