METHOD FOR DETERMINING TRACE IMPURITIES OF ARSENIC AND STIBIUM IN VEGETABLE MEDICAL MATERIAL

摘要

FIELD: chemistry.;SUBSTANCE: invention relates to analytical chemistry and specifically to method for determining trace impurities of arsenic and stibium in herbal drug raw material. Method of converting arsenic compounds and antimony into appropriate hydrides by reducing mix containing 40 % solution of potassium iodide, 10 % solution of ascorbic acid, 4 M solution of hydrochloric acid and zinc metal. Analysed sample containing arsenic and antimony is transferred into liquid form, and for switching to hydrides two parts are taken, wherein one part, for removing arsenic, is treated with concentrated hydrochloric acid, evaporated and dry residue is dissolved in 4 M solution of hydrochloric acid, then, cell containing absorbing solution containing 0.5 M solution of potassium iodide, acetate buffer solution with pH 5.6 and mixture of auramine sensibilisators: fluorescein:sodium eosinate mixture in molar ratio 1:1:1 blown with air for 1-2 minutes and irradiated with light-emitting diode lamp until formation of photo generated iodine. Distillation of hydrides from both parts of analysed sample through photo generated iodine is performed till change of quantity of iodine in cell, which is determined amperometric by variation of intensity of current in circuit. After distillate of hydrides solution in absorbing cell is again blown with air oxygen and exposed to establish initial quantity of iodine in it and by variation of intensity of current and time of iodine generation in cell is determined on amount of arsenic and stibium.;EFFECT: method described above, increases accuracy and detection limit of arsenic and stibium in herbal drug raw material.;1 cl, 5 tbl, 2 ex