Mikhailova L. Application of catalytic indicator reactions of complexation for determination some oxigen-bearing anions in functional materials

Object of investigation: indicator reaction of formation in the subacidic environment of complexes of aluminium (III) with xylenol orange catalyzed by hydrocarbonate-ions, and indicator reaction of cobalt (III) with nitroso-R-salt catalyzed by dihydrophosphate-ions. Aim of investigation: searching, studying and application of catalytic reactions for high-sensitivity determination of carbonate and phosphates - ions in alkaline metals halides single crystals and in pure raw materials. Methods of investigation: photometric variant of catalytic determination, coulometry, рН, titrimetric analysis, oriented crystallization of water-salt eutectics. Theoretical and practical results: a new indicator reaction for СO32- and РO43- determination is suggested. Influence of reagents' concentrations and accompanying ions on the rate of catalytic indicator reactions is investigated and optimal conditions for determination of cata-lysts are found. It is shown that participating of surfactants in chelation processes affects on its kinetics. This phenomenon was used to improve sensitivity of catalytic ions determination. The methods for direct determination of carbonates (down to 0.8 ppm) and phosphates (down to 0.5 ppm) in alcaline metals halides is proposed. Using of crystallization preconcentration with catalymetric analysis of concentrates allows to determine of carbonates down to 0.01 ppm. It is shown that proposed reactions can be used for simultaneous determination of two catalysts whithout preliminary separation or masking. An algo-rithm of data processing for multicomponent catalytic analysis is proposed. Degree of inculcation: the developed methods have been introduced into the practice of work of STC "Institute for Single Crystals". Field of application: analytical chemistry of functional materials.