Complexation of Alkaline-Earth Metals with Bisazosubstituted Chromotropic Acid Derivatives on Fibrous Ion Exchanges

The method of diffuse refection has been used for the investigation of complexation reactions between Mg, Ca, Sr, and Ba ions (2+) with bisazosubstituted chromotropic acid derivatives after their sorption on a solid phase. Different adsorbents and methods of the immobilization of metal ions and organic reagent have been tested. The influence of pH on the sorption and subsequent reaction between alkaline-earth metals and organic reagents has been studied. The dependence of analytical signals on the reagent nature has been discussed. Systems have been proposed for the determination of the total concentration of Ca, Sr, and Ba and also Sr and Ba in the concentration range n x 10(-4) M; these systems include the sorption of elements on the solid phase of polyacrylonitrile fiber loaded with the Chelex-100 ion exchanger from the solution with pH 7.0 +/- 0.5, subsequent treatment of discs with the solutions of Carboxynitrazo or Ortanyl B and the measurement of the coefficients of diffuse refection.