Аннотация:approach to the simultaneous isolation of As(III) and Se(IV) from solutions on a new S,N-containing sorbent followed by determination of the analyte in the sorbent phase by total reflection X-ray fluorescence (TXRF) is proposed. To match the goal, a sorbent with a branched structure is synthesized on the basis of polyacrylamide modified with formaldehyde and hydrogen sulfide. This is a heteroatomic copolymer containing sulfide bridges and crosslinking by a tertiary amine in its chain. Conditions for the uantitativecoextraction of As(III) and Se(IV), namely, sorption in 1 M solutions of HNO3 in the presence of calcium ions, heating up to 60°C, and phase contact time of 1 h, are determined. The mechanism of sorption interaction of the analytes under specified conditions is discussed. It is found that 100-fold excesses of iron, zinc, and copper do not interfere with the extraction of the analytes; therefore, it is possible to apply the sorbent for the extraction of As(III) and Se(IV) from different types of raw materials and processed products. A procedure for the direct X-ray fluorescence quantification of arsenic and selenium with Sr of 0.09 and 0.08, respectively, in the sorbent phase is developed. The correctness of the results is confirmed by ICP-MS upon theanalysis of aqueous reference solutions after the dissolution of the sorbate in HNO3 (1 : 1).
