| Ionic liquids have high ionic conductivity, wide electrochemical stability window,non-volatility, high ion density, and good thermal stability. They are very useful in many fields including electrochemical sensors. Iron is a vital trace element for the growth of organisms in many parts of the coastal waters. It is important to detection of the total dissolved iron in coastal waters. Chemical modified electrode offers the advantages of easy fabrication, low cost, good portability, and high sensitivity and selectivity. In this thesis, three chemical modified electrodes were designed by using Ionic liquid and nano materials. The content is as follows:1. Electrochemical determination of iron in coastal waters based on ionic liquidreduced graphene oxide supported gold nanodendritesIL-rGO as a soft support could provide large specific surface area for Au NDs and make them smaller size and unique form, which would benefit to the electrochemical reduction of iron. Nafion is employed as a cation exchange polymer in which IL-rGO and Au NDs can be tightly attached to the electrode surface. The proposed sandwich structured IL-rGO/Au NDs/Nafion modified electrode shows excellent electrochemical properties. The IL-rGO/Au NDs/Nafion modified electrode combined individual advantages as a whole and showed good responses for iron ions. Under the optimized conditions, the reduction peak currents of iron have a good linear relation with its concentrations ranging from 0.30 to 100 ?mol/L with the detection limit of 35 nmol/L.More importantly, this sandwich structured modified electrode had a good antiinterference ability and successfully applied in the determination of the total dissolved iron in coastal waters.2. Ionic liquid nano-gold electrodes applicated to the determination of iron in pore waterA novel gold electrode was fabricated through surface nanostructuration and modified by a cation exchange membrane, it has an excellent response for the determination of Fe(III). Based on the surface nanostructuration for gold electrode, a large specific surface area was obtained, and the reduction peak of gold was disappeared.The modified electrode showed excellent sensitivity for determination of total dissolved iron in coastal water samples. The electrode surface was coated with Nafion to capture more Fe(III) from aqueous solution by cation exchange. It was beneficial to the reduction of Fe(III). The novel electrode has high sensitivity because of the synergy of the Nano-Au and Nafion. Under the optimal conditions, the reduction peak current of Fe(III)showed a good linear relation with its concentrations ranging from 0.30 to 100 ?mol/L and the detection limit of 15 nmol/L. It is satisfactory for the determination of the total dissolved iron in pore waters.3. The preparation and application of ionic liquid-titanium carbide nanoparticle gel modified electrodeThe novel gel composite, based on the ground of ionic liquid(1-butyl-3-methylimidazolium hexafluorophosphate, BMIMPF6) and titanium carbide(Ti C)nanoparticles, was used to modify glassy carbon electrode and applied to the electrochemical determination of tryptophan(trp). The physical and electrochemical characterizations of the BMIMPF6-Ti C gel modified electrode were studied in detail by scanning electron microscopy, energy dispersive X-ray spectroscopy, cyclic voltammetry,and differential pulse voltammetry methods. Due to the large specific surface area and strong adsorption property of Ti C nanoparticles, as well as the good ionic conductivity and strong electrocatalytic property of BMIMPF6, the oxidation peak current of trp at BMIMPF6-Ti C gel modified electrode showed good linear relation with its concentrations ranging from 0.50 to 30 ?mol/L and 30 to 500 ?M, respectively. The detection limit was 53 nmol/L. The as-prepared BMIMPF6-Ti C gel modified electrode had good antiinterference ability and can be successfully applied in the electrochemical determination of trp in real food samples. |
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