Determination of the peroxide anion radical in water by the chemiluminescent method

Abstract

Introduction. The necessity of the analysis of peroxide anion radicals in the aqueous medium as the main element performing a special role in the management of internal processes in the body is substantiated. 
 Goals and objectives of the study. Creation of methodological support for the determination of a superoxide anion radical in drinking waters, providing metrological characteristics of parameterization of its systemic homeostatic action in a biologically significant concentration range. The task of the study was to find a method and optimal conditions for determining the concentration of peroxide anion radical in drinking waters that differ in their electrochemical parameters.
 Materials and methods. As an analytical instrument for measuring ultra-low concentrations of hydrogen peroxide in water (more than 0.1 µg/l), a kinetic chemiluminescent analyzer was used (liquid chemiluminescent analyzer “LIK Universal”, TU 9443-001-42844321-03).) Parametrization of the ratio of anion-radical and free molecular forms of hydrogen peroxide in the specified range of its concentrations in water was carried out by HPLC. A capillary cryophysical method based on the selection of chains of self-similar aqueous associates was used to estimate the dimensional parameters of the associates of peroxide anion radicals.
 Results. The dependence of the integral chemiluminescence intensity on the concentration of superoxide anion radicals in water was established to be linear only in the range of peroxide concentrations from 0 to 40 µg/l. At the same time, the time to reach the maximum intensity of the glow depends on the concentration of the peroxide anion radical in water. By studying the dimensional parameters of associates of peroxide anion radicals from the content of hydrogen peroxide in water, it was found that in the range of ultra-low concentrations they practically do not change for a sufficiently long time, which is due to the stability of the isomerism of water molecules in this concentration range.
 Limitations. The objects, composition, quantitative limits and conditions for measuring anion radical peroxide using this technique apply to drinking water, the quality and control methods of which are regulated by regulatory documents of the international community.
 Conclusion. A method for estimating the content of peroxide-anion radical in water based on the use of a kinetic chemiluminescence method with a sensitivity 
 of about 10–1 µg/l in small volumes of water (50–200 µl) has been developed, which has sufficient accuracy and reproducibility for practical purposes.