Electroanalytical exploitation of quinoneâ thiol interactions: application to the selective determination of cysteine
Hignett, Geraldine; Threlfell, Sarah; Wain, Andrew J.; Lawrence, Nathan S.; Wilkins, Shelley J.; Davis, James; Compton, Richard G.; Cardosi, Marco F.; Hignett Geraldine; Physical and Theoretical Chemistry Laboratory, University of Oxford; Threlfell Sarah; Physical and Theoretical Chemistry Laboratory, University of Oxford; Wain Andrew J.; Physical and Theoretical Chemistry Laboratory, University of Oxford; Lawrence Nathan S.; Physical and Theoretical Chemistry Laboratory, University of Oxford; Wilkins Shelley J.; Physical and Theoretical Chemistry Laboratory, University of Oxford; Davis James; Physical and Theoretical Chemistry Laboratory, University of Oxford; Compton Richard G.; Physical and Theoretical Chemistry Laboratory, University of Oxford; Cardosi Marco F.; Department of Biological Sciences, University of Paisley
Журнал:
Analyst
Дата:
2001
Аннотация:
Square wave voltammetry was applied to the detection of cysteine through the use of an indirect assay that exploits the reaction of the thiol with a quinone indicator. Voltammetric discrimination between unreacted quinone and the corresponding quinoneâ cysteine adduct is possible with clear resolution of the latter peak providing a linear response from 5 to 47 μM. The selectivity of the approach was assessed with no interference from cystine, lysine, paracetamol or 4-aminophenol. The response recorded in the presence of a massive excess of ascorbic acid was also investigated and the integrity of the approach confirmed. The effects of other sulfhydryl thiols, homocysteine and glutathione, were also assessed and found to present no appreciable change in the voltammetric profile. The practical utility of the approach was investigated through examining the response to cysteine in urine.
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