Development of novel techniques for monitoring anti-oxidant thiols

The clinical exploitation of physiological biomarkers could yield considerableimprovements in diagnosis and treatment providing their measurement can be conducted peedily and preferably at the point of care. The project has sought to investigate the development of new methods that could allow such measurements to be made. The various biomarkers that could be exploited as the basis of a general “index” of physiological wellbeing have been identified and their potential clinical merit critically appraised. Anti-oxidant sulphur compounds (cysteine, glutathione, sulphite) were selected as potential targets on the basis of their physiological role in protecting the body from damage by free radicals. The variation in their concentration within biofluids is widely acknowledged as a useful diagnostic gauge as to the degree of oxidative stress that an individual may be experiencing. The main problem, from a clinical perspective, is the lack of a suitable procedure for monitoring their concentration speedily at, or by, the patient. A brief assessment of the various electroanalytical options (encompassing voltammetric, amperometric and potentiometric methodologies) available for the detection of the sulphur anti-oxidants has been conducted. A potentiometric detection strategy was found to offer numerous advantages and a novel indicator family based on quinone interaction adopted and forms the foundation of the work presented herein. The reaction mechanism has been elucidated and the analytical applicability of the system investigated using a variety of techniques – covering both chromatographic, spectroscopic and electrochemical methodologies