Preconcentration of arsenic(V) as molybdoarsenic heteropoly acid by dynamic sorption

摘要

The sorption of molybdoarsenic heteropoly acid (MAA) and its ion pair with tri-n-octylamine (TOA) on sorbents of different nature and hydrophobic filters has been studied. It is demonstrated that MAA is efficiently extracted on the polyacrylate sorbent Amberlyte XAD-8; the distribution coefficient of arsenic is 1 x 10~4 cm~3/g for the sorption from 0.35-1.5 M H_2SO_4. Conditions of the quantitative extraction of MAA in the presence of TOA on thin-layer cellulose triacetate filters are found. A procedure is proposed for the sorption X-ray fluorescence determination of arsenic in potable water. The detection limit of arsenic is 10 #mu#g/L for the sorption from 100 mL of a solution.