| Electrochemiluminescence （ECL） is the luminescence generated by the relaxation ofexited state substances that are produced by an electrochemically initiated reaction. The mostextensively used ECL reagent is Ru（bpy）32+owing to its high sensitivity and great stability.However, the liquid phase of Ru（bpy）32+ECL system can bring about environmental pollutionand high costs. Hence, immobilizing Ru（bpy）32+on the electrode surface, as one means, cannot only reduce the consumption of reagent but also simplify the experimental configuration.Although the problem associated with the reagent consumption could be solved byimmobilization strategy, another key issue related with the poor selectivity of the ECLdetector still exists. Therefore, tedious pretreatments are required to eliminate interferences.Molecular imprinting technology （MIT） is able to provide high recognizability and selectivityfor analytical measurements. Molecular imprinting polymer （MIP） can separate and enrich thetarget molecule from the complex samples, which can not only eliminate the interferences butalso provide higher sensitivity. A new ECL-MIP sensor was proposed based on theincorporation of ECL and MIT. The sensor had shown high sensitivity, good selectivity andreproducibility. The content of this thesis was divided into three main sections:1. Ru（bpy）32+/Nafion/MWCNT modified electrode was fabricated and the experimentalconditions were optimized. It was found that when the modification amount was3μL, theperoid of adsorption in Ru（bpy）32+solution （1×10-3mol/L） was30min, the pH of PhsphateBuffer Solution（PBS） was7.1and the cyclic voltammetry scan rate was0.1V/s, the ECLintensities showed a linear relationship with the logarithm of the2-（dibutylamino）ethanol（DBAE） concentrations （log c） in the range of1.0×10-111.0×10-7mol/L and the regression equation was IECL=17.2log c+206, with the correlation coefficientof0.9967. The detection limit could be as low as3.5×10-12mol/L. In addition, differentconcentrations of heroin, codeine, methamphetamine, ephedrine were respectively detected bythe Ru（bpy）32+/Nafion/MWCNT modified electrode.2. The sol-gel MIP sensor was fabricated to detect heroin. The ratio of components andthe parameter of preparation process were optimized by the orthogonal experiment. An aliquotof40μL TEOS,20μL PTMOS,5μL MTMOS,80μL HCl （0.004mol/L） were mixed withconstant stirring for60min and then aged for12h and finally an aliquot of10μL0.01mol/Lheroin was added as the template. Subsequently, an aliquot of3μL solution was modified onthe glassy carbon electrode and then the film was left to dry for6h at room temperature. Theremoval of the heroin template from the flm was achieved by rinsing with water at50°C.Using the sol-gel MIP sensor to detect different concentrations of heroin by differential pulsevoltammetry（DPV） method. A linear relationship was obtained between the logarithm of theheroin concentrations（log c） and the DPV oxidation peak currents in the range of1.0×10-101.0×10-6mol/L and the regression equation was I （μA）=-0.0395log c-0.392, withthe correlation coefficient of0.9956.3. Based on the research of first two chapters, the combination of ECL and MIT wasutilized to fabricate ECL-MIP sensor and then applied to the detection of heroin. When theincubation time was5min and the test conducted in PBS （pH7.0） at a scan rate of0.1V/s, the ECL intensities showed a linear relationship with the logarithm of the heroinconcentrations（log c） in the range of1.0×10-141.0×10-10mol/L and the regression equationwas IECL=36.7log c+550，with the correlation coefficient of0.9998. The detection limitreached to4.0×10-15mol/L. Due to the high selectivity, the ECL-MIP sensor could directlydetect the drug in the diluted urine and saliva and the detection limit was up to1.35×10-12mol/L. The sensor could also detect hiding heroin by collecting and absorbing the volatile ofheroin. |
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