ABSTRACT
The complexity of biological objects and the rapid change in their composition after sampling, the variety of compounds of different chemical nature, possessing oxidative and antioxidant properties, make the task of its estimating extremely nontrivial and important for food, nutrients and human health characterization. The paper discusses the use of potentiometry in determining integral antioxidant/oxidant activity mainly of biological fluids and human skin. The source of information is the electrode potential shift that occurs when the analyzed object is inserted in the solution of the mediator system or when the mediator system is exposed to human skin. The experimental approaches, protocols, calculations are described. A number of examples of antioxidant activity and oxidative stress estimation in medicine are presented. The works show lower levels of antioxidant activity (AOA) of plasma and blood serum in patients with cardiovascular diseases, obesity, and malignant neoplasms as compared with the healthy volunteers. It was found out that antioxidant activity of fertile men semen is higher than AOA of infertile patients. Using the method discussed have shown that in some infertile male patients antioxidant activity of semen has been accompanied by oxidant activity. It has been found, that antioxidant activity of skin increases after intake of ascorbic acid and vitamin-enriched juices. The described approach holds considerable promise for monitoring oxidative stress of the whole organism and its systems, and for selecting effective and safe therapy. Thus, it opens up new opportunities in expanding the use of analytical chemistry in such an important field as medicine.
Subject(s)
Antioxidants/metabolism , Medicine , Oxidative Stress , Potentiometry/methods , Disease , HumansABSTRACT
The review covers over 230 papers published mostly in the last 5 years. The goal of the review is to attract the attention of researchers and users to stripping voltammetry in particular, its application in environmental monitoring and analysis of foodstuffs. The sensors employed are impregnated graphite, carbon paste, thick film carbon/graphite and thin film metallic electrodes modified in-situ or beforehand. Hanging mercury drop electrodes and mercury coated glassy carbon electrodes are also mentioned. Strip and long-lived sensors for portable instruments and flow through systems are discussed as devices for future development and application of stripping voltammetry.
Subject(s)
Environmental Monitoring/instrumentation , Food Analysis/instrumentation , Electrochemistry , Electrodes , Environmental Monitoring/methods , Food Analysis/methodsABSTRACT
The possibilities of voltammetry as a source of information in bioelectrochemistry, electro-chemistry solid-state chemistry and analytical chemistry are reviewed. Attention is drawn to the use of catalytic currents and adsorption, inverse voltammetry, and solid and modified electrodes. The review mainly covers papers published in 1983 and 1984, especially those in the Soviet literature.
ABSTRACT
A method is suggested for the determination of traces of antimony by inverse voltammetry of the solid phases formed with triphenylmethane dyes (Crystal Violet, Methyl Violet and Malachite Green) as the precipitants. The authors have studied the effect of concentration, adsorption and oxidation of the triphenylmethane dyes, potential and time of pre-electrolysis, and concentration of antimony(III) and some other elements on the polarogram shape and stripping current. A method for determining antimony traces in chromic salts is described as an example.
ABSTRACT
Film stripping voltammetry is a new electrochemical analytical method consisting in concentrating the test substance in the form of a metal or a sparingly soluble compound on the electrode surface and subsequently recording the current for electrodissolution of the deposit. The method has been worked out for determination of metal ions, anions and variable valence ions, with sensitivities as low as 10(-9)M. As indicator electrodes, solid, usually graphite, electrodes and stationary mercury electrodes are used.
