Spectrophotometric investigation of the ternary beryllium systems with some triphenylmethane reagents and cationic surfactants

Chrome azurol S, eriochrome cyanine R and pyrocatechol violet have been investigated as the chromogenic reagents for spectrophotometric determination of beryllium in the presence of cationic surfactants: cetyltrimethylammonium bromide, cetylpyridinium chloride, tetradecyldimethylammonium bromide and cetyldimethylbenzylammonium chloride. Among the examined twelve ternary systems the best as a basis for the most sensitive spectrophotometric method for Be determination is Be-CAS-zeph one. The molar absorptivity of this method is 1.10 x 105 l x mol-1 x cm-1 at 620 nm. By means of this precise method, Be has been determined in the contact of light-emitting diode. However the new methods based on ternary systems with pyrocatechol violet and cationic surfactants are not so sensitive (ε = 3.6-4.8 x 104 at 650 nm), they can be recommended for rapid determination of larger amounts of Be (in these systems there is not necessary to heat sample solutions for completing colour development). 2 figs., 4 tabs., 21 refs. (author)