METHOD FOR SEPARATE DETERMINATION OF 0-2-ETHYLHEXYLMETHYLPHOSPHONATES OF ZINC AND CALCIUM IN STABFON PREPARATION Russian patent published in 1994 - IPC

FIELD: analytical chemistry. SUBSTANCE: method involves dissolving a charge of sample in a chloroform-ethyl alcohol mixture, adding a surplus of solution of potassium or sodium fluoride for fixing Ca cations, mixing vigorously, adding distilled water, buffer solution (pH 9.5-10.0) and titrating with 0.05 N solution of di-Na-EDTA in presence of indicator eriochrome black T. On the basis of tittering data, the mass fraction is calculated of 0-2-ethylhexylmethylphosphonate of zinc. The other charge of the sample is dissolved in a mixture of chloroform-ethyl alcohol, then distilled water is added, buffer solution pH 9.5-10.0 and tittered with 0.05 solution of di-Na-EDTA in presence of indicator eriochrome black T. On the basis of tittering data the summary mass fraction is calculated of 0-2-ethylhexylmethylphosphonates of zinc and calcium. The mass fraction of 0-2-ethylhexylmethylphosphonate is calculated by the difference of titration results with and without addition of potassium or sodium fluoride. EFFECT: higher efficiency. 3 tbl