Test determination of aniline in solutions based on azo coupling with analytical reagents incorporated into silicic acid xerogels

Silicic acid xerogels modified with 1-naphthol, 2-naphthol, 8-hydroxyquinoline, 2,7-dihydroxynaphthalene,N-(l-napthyl)ethylenediamine andp-hydroxydiphenyl were synthesized. It was shown that the immobilized reagents can participate in reactions of azo coupling with products of aniline diazotization. The best (among the studied) immobilized reagent for determining aniline was 1-naphthol. Xerogel modified with 1-naphthol was used for determining aniline in solutions by solid-phase spectrophotometry and with visual detection. The analytical ranges for aniline at the optimal conditions were 0.005-10 mg/L using solid-phase spectrophotometry and 0.05-15 ng/L with visual detection. The results were verified in the analysis of synthetic mixtures.