Svetlana Gracheva

University of Surrey, Guildford, ENG, United Kingdom

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Publications (4)23.61 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: The reaction of benzoquinone with reduced thiol species has been investigated using potentiometric techniques. The specificity of this reaction for thiol functionality has been briefly assessed and the nature of the electrode response has been elucidated. The system has been characterized in terms of selectivity, sensitivity and the efficacy of using the system for the quantification of thiol containing pharmaceuticals has been demonstrated. The simplicity of the detection methodology is shown to markedly contrast alternative thiol detection strategies. The transfer of the technology to a mass production format through the adoption of screen print electrode formats has been achieved and the efficacy of the approach demonstrated. Recovery experiments using captopril and penicillamine in tissue culture as a model analyte system were performed.
    Electroanalysis 11/2004; 17(3):205 - 209. · 2.82 Impact Factor
  • Svetlana Gracheva, Callum Livingstone, James Davis
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    ABSTRACT: The reaction of naphthoquinone with physiological thiols has been investigated as the basis of a NPT strategy for the measurement of the latter. Screen-printed carbon electrode assemblies provide an inexpensive and inherently disposable platform for the detection methodology. The key analytical parameters underpinning the selective and sensitive (0.4 uM-1 mM) determination of reduced thiol have been assessed, and the clinical efficacy of the approach has been demonstrated through its application to the analysis of human plasma. The results have been corroborated using standard techniques, and the routes through which the system can be adopted within mainstream biomedical environments are highlighted.
    Analytical Chemistry 08/2004; 76(13):3833-6. · 5.70 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: The potentiometric responses of mono- and macromolecular thiol species derivatized with a naphthoquinone indicator have been assessed at electrode designs based on laminated carbon fiber assemblies. The nature of the response for each type of species was found to depend strongly on the electrode geometry and composition and can be used to discriminate between the different thiol moieties. The efficacy of the electrode systems for the measurement of plasma thiols within normal and diabetic blood samples has been assessed, and a possible mechanism for the differing responses has been proposed.
    Journal of the American Chemical Society 07/2004; 126(25):7732-3. · 10.68 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: The potentiometric response resulting from the sequential addition of reduced thiols to a benzoquinone/hydroquinone couple has been investigated. The system has been shown to offer a simple route through which thiol could be quantified but a discrepancy in the reaction stoichiometry between glutathione and cysteine was observed. A mechanistic appraisal of the quinone–thiol interactions has been conducted and the proposed reaction pathways corroborated by spectroscopic analysis.
    Electrochemistry Communications 01/2003; 5(8):732-736. · 4.43 Impact Factor