Influence of electrode potential on the electrochemical behavior of a 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF₄) solution containing 5 wt % 1-ethyl-3-methylimidazolium bromide (EMImBr) has been investigated using electrochemical and synchrotron-initiated high-resolution in situ X-ray photoelectron spectroscopy (XPS) methods. Observation of the Br 3d in situ XPS signal, collected in a 5 wt % EMImBr solution at an EMImBF₄⁻vacuum interface, enabled the detection of the start of the electrooxidation process of the Br⁻ anion to Br₃⁻ anion and thereafter to the Br₂ at the micro-mesoporous carbon electrode, polarized continuously at the high fixed positive potentials. A new photoelectron peak, corresponding to B⁻O bond formation in the B 1s in situ XPS spectra at ≤ ⁻1.
View Article and Find Full Text PDFThree different electroanalytical techniques for the detection of manganese in marine sediments are evaluated. The anodic stripping voltammetry of manganese at an in situ bismuth-film-modified boron-doped diamond electrode and cathodic stripping voltammetry at a carbon paste electrode are shown to lack the required sensitivity and reproducibility whereas cathodic stripping voltammetry at a bare boron-doped diamond electrode is shown to be reliable and selective with a limit of detection, from applying a 60s accumulation period of 7.4 x 10(-7)M and a sensitivity of 0.
View Article and Find Full Text PDFThis aim of this paper is to expound the complexity of thiol redox systems in the endoplasmic reticulum of eukaryotic cells to the electroanalytical community. A summary of the state of the art in electrochemical methods for detection of thiols gives an insight into the challenges that need to be addressed to bridge the disparity between current analytical techniques and applications in a 'real' biological scenario.
View Article and Find Full Text PDFChem Commun (Camb)
January 2006
Two types of calix[4]arene derived hosts for anions with, respectively, 1,3-alternate and cone conformations have been prepared; the 1,3-alternate system binds dicarboxylate anions in a ditopic manner while the cone compounds are deprotonated by carboxylates.
View Article and Find Full Text PDFWe report the electroanalytical determination of lead by anodic stripping voltammetry at in-situ-formed, bismuth-film-modified, boron-doped diamond electrodes. Detection limits in 0.1 mol L(-1) nitric acid solution of 9.
View Article and Find Full Text PDFBismuth-modified glassy carbon electrodes have been investigated for their suitability in sonoelectroanalysis. The stability of the bismuth film to the application of ultrasound was assessed via voltammetric and atomic force microscopy (AFM) studies which revealed little ablation at powers up to an intensity of 130 W cm(-2) delivered from a 25-kHz sonic horn. Furthermore, bismuth-film-modified glassy carbon electrodes were evaluated for the sonoelectroanalytical quantification of zinc and cadmium.
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