1-butyl-3-methylimidazolium-hexafluorophosphate and titanium-dioxide

Nonelectroactive acetochlor can be indirectly determined through the photocatalytical degradation of acetochlor. A derivative visible light photoelectrochemical sensor for indirect detection of the herbicide acetochlor using TiO2-poly(3-hexylthiophene)-ionic liquid nanocomposite is constructed. Poly(3-hexylthiophene) (P3HT) was synthesized via chemical oxidative polymerization with anhydrous FeCl3 as oxidant, 3-hexylthiophene as monomer, chloroform as solvent, and the functional TiO2 nanoparticles were facilely prepared by blending TiO2 nanoparticles and P3HT at room temperature ionic liquid, 1-Butyl-3-methylimidazolium hexafluorophosphate solution. Operational parameters, including the photolysis time, ratios of TiO2 to P3HT, bias voltage and pH of buffer solution have been optimized. Under optimal conditions, the proposed photoelectrochemical method could detect acetochlor ranging from 0.5 to 20 μmol L(-1) with a detection limit of 0.2 nmol L(-1) at a signal-to-noise ratio of 3. The assay results of acetochlor in water samples with the proposed method were in acceptable agreement with those of the gas chromatograph-mass spectrometer (GC-MS) method. The promising sensor opens a new opportunity for fast, portable, and sensitive analysis of acetochlor in environmental samples.

Topics: Carbon; Electrochemical Techniques; Electrodes; Herbicides; Imidazoles; Ionic Liquids; Light; Nanocomposites; Photochemical Processes; Thiophenes; Titanium; Toluidines

TiO(2)-graphene nanocomposite was prepared by hydrolysis of titanium isopropoxide in colloidal suspension of graphene oxide and in situ hydrothermal treatment. The direct electrochemistry and electrocatalysis of hemoglobin in room temperature ionic liquid 1-Butyl-3-methylimidazolium hexafluorophosphate, chitosan and TiO(2)-graphene nanocomposite modified glassy carbon electrode were investigated. The biosensor was examined by using UV-vis spectroscopy, scanning electron microscopy and electrochemical methods. The results indicated that hemoglobin remained its bioactivity on the modified electrode, showing a couple of well-defined and quasi-reversible redox peaks, corresponding to hemoglobin Fe(III)/Fe(II) couple. The kinetic parameters for the electrode reaction, such as the formal potential (E(o')), the electron transfer rate constant (k(s)), the apparent coverage (Γ), and Michaelis-Menten constant (K(m)) were evaluated. The biosensor showed good electrochemical responses to the reduction of H(2)O(2) in the ranges of 1-1170 μM. The detection limit was 0.3 μM (S/N=3). The properties of this composite film, together with the bioelectrochemical catalytic activity, could make them useful in the development of bioelectronic devices, and investigation of electrochemistry of other heme proteins at functional interface.

Topics: Biosensing Techniques; Catalysis; Chitosan; Electrochemical Techniques; Electrodes; Graphite; Hemoglobins; Hydrogen Peroxide; Imidazoles; Ionic Liquids; Nanocomposites; Oxidation-Reduction; Sensitivity and Specificity; Temperature; Titanium