| Nanoparticles provide unique electrical and chemical properties and have attracted much research interest, such as electrochemistry and electroanalytical chemistry. Among various electron transfer mediators, metal hexacyanoferrates (MHCF), a class of polynuclear metal hexaeyanoferrate, have attracted much attention since the pioneering work of Prussian blue (PB). To improve the stability and analytical performance of the modified electrodes, convenient methods were investigated in the preparation of chemically modified electrodes. Six kinds of hexacyanoferrates including Nano-CuHCF, Nano-NiHCF/PPyox, Nano-PB/PPyox, Nano-NiHCF/PB, HCF/PPy and MWNT/HCF/ PPy were electrochemical deposition on carbon ceramic composite electrodes (CCE). The electrochemical and electrocatalytic activity of the above electrodes were investigated using electrochemical and scanning electron microscopy methods. Additionally, two kinds of carbon paste modified electrodes (CPE) including Nano- CeO2/CPE and multi-walled carbon nanotubes modified CPE were fabricated. These two kinds of nanoparticles modified CPE were used in the determination of clenbuterol and established the corresponding electrochemical detection methods. The research possessed potential applications in improving the stability and broaden the analytical chemistry of modified electrodes.This thesis carefully studied the preparation, characterization, electrochemical properties and electrocatalytic activity of the following modified electrodes. The main contents were as follows:1. Two kinds of metal hexacyanoferrates modified CCE, Nano-CuHCF/CCE and Nano-PB/PPyox/CCE, were fabricated using cyclic voltammetry from the solution containing HAuCl4 and EDTA. Additionally, Nano-NiHCF was deposited on the surface of PPyox modified CCE in the presence of EDTA. The possible mechanism was investigated by using electrochemical and SEM techniques and the electrodeposition conditions were optimized. The results showed that, EDTA controlled the efficient concentration of mental ions in solution, while the gold particles deposited on the electrode surface provided heterogeneous crystal seeds once they had been produced and thus speeded up the rate of MHCF deposition. Under the synergic action of EDTA and HAuCl4, uniform and compact films were formed. Additionally, the presence of PPyox film further enhanced the deposition rate of PB on the electrode surface. The Nano-CuHCF/CCE and Nano-NiHCF/PPyox/CCE had strong electrocatalytic activity toward the oxidation of hydrazine, while the Nano-PB/PPyox/CCE had electrocatalytic activity toward the reduction of H2O2. The heterogeneous catalytic reaction rate constants by chronoamperometry were 1.4×10(4 for Nano-CuHCF, 4.83×10(4 for Nano-NiHCF/ PPyox, and 7.73×10(3 L·mol-1·s-1 for Nano-PB/PPyox with the sensitivity of 194.0,110.0 and 220.0μA·(mmol·L-1)-1, respectively.2. A Nano-NiHCF/PB film modified CCE was typically fabricated in the presence of EDTA, Ni2+, Fe3+ and K3Fe(CN)6 using cyclic voltammetry method. The electrochemical properties and electrocatalytic activity toward H2O2 was studied. The results showed that, the Nano-NiHCF/PB exhibited two pair of redox peaks, which were quite different from the redox peaks of PB, indicating that the mixed material wasn't seems to be a simple mixture of hexacyanoferrates of nickel and iron, that Ni2+ occupies certain position of PB lattice. Compared with single metal hexacyanoferrates electrodes, the Nano-NiHCF/PB/ CCE exhibited perfect stability in acidic, neutral and weak alkaline solution and showed high electrocatalytic activity toward the reduction of H2O2. The calibration curve was over the range of 7.94×10-6 to 2.30×10-2 mol·L-1 with a detection limit of 2.50×10-6 mol·L-1, and the sensitivity to H2O2 reduction was 77.50μA·(mmol·L-1)-1.3. Fe(CN)64- doped polypyrrole composite film modified electrode was electro- chemical deposited on bare CCE and multi-walled carbon nanotubes dropped CCE using cyclic voltammetry, and the HCF/PPy/CCE and MWNT/HCF/PPy/CCE were fabricated. The electrocatalytic properties of both modified electrode were studied. Experiments showed that the two kinds of modified electrodes had strong electrocatalytic activity toward the reduction of H2O2 and NO2-. Amperometric detection of H2O2 and NO2- were in the linear ranges of 2.0×10-6 2.4×10(-3 mol·L-1 and 1.5×10-6 1.8×10-3 mol·L-1, the detection limits were 7.0×10-7 and 3.0×10-7 mol·L-1 with the sensitivity of 61.30 and 81.39μA·(mmol·L-1)-1, respectively, and both of the corresponding time were less than 5s.4. Nano-CeO2 was synthesized by all-solid-phase method and a Nano-CeO2/CPE was prepared. On the other hand, a MWNT/CPE was also prepared. Comparing with that of a bare electrode, the current of clenbuterol was greatly increased at above modified electrodes. Based on this, differential pulse voltammetric methods for the determination of clenbuterol were established. The methods were applied in the determination of clenbuterol in simulated urine and blood samples. Under the optimum conditions, linear dependences of the catalytic current versus the concentration of clenbuterol were obtained in the ranges of 5.0×10-9 6.0×10(-6 and 2.0×10-9 1.0×10-5 mol·L-1 with the detection limits of 2.5×10-9 and 7.0×10-10 mol·L-1.
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