Micro-determination of As(V), V(V), Mo(VI), W(VI) in the presence of Cu(II), Ni(II) and Zn(II)

A rapid procedure is described for the separation and determination of 0.025 mg to 1.0 mg quantities of As(V), V(V), Mo(VI) and W(VI) from small quantities of Cu(II), Ni(II), and Zn(II) using silica gel as a selective sorbent for the cations. The individual anionic components, which remain in the supernatant solution after separation from the cations, are determined by colorimetric methods. The complete recovery of As(V) in supernatant solution has also been tested radiometrically using 76As as radioactive indicator. The sorbed cations after extraction with dilute hydrochloric acid are determined by EDTA titrations. The tabulated results indicate that even microgram quantities of amins may be recovered free from their cationic contaminants. The capacity is around 1.5 mg ion/g silica gel. The method is useful for the complete analysis of binary mixtures. (T.G.)