The technology of the selective precipitation of arsenic from solutions for its detection and isolation

Abstract

This is a technology of the selective precipitation of (AsO₄)³⁻ from solutions as the Fe³⁺ hydroxoarsenate using the FeCl₃, NaHCO₃ and CH₃CO₂H. This can be used as a qualitative reaction for arsenic. The dissolving of the Fe³⁺ and Ag⁺ arsenates in CH₃CO₂H in the presence of the CH₃CO₂Na is discovered. The Fe³⁺ acetate is stable in water solution without other reagents (it was discovered); and it is stable in CH₃CO₂H solutions. The arsenic can be isolated using the reactions: Fe³⁺ hydroxoarsenate + reducing agents, example: Ca(H₂PO₂)₂, as the dark amorphous precipitate (like soot). Then it can be sublimated. This is a safe easy reliable highly sensitive alternative to the Marsh test.