Dialkyltin salts as extractants in methods for the determination of arsenic and phosphorus

Dialkyltin salts are suitable as extractants for various oxygen-containing anions. They are particulary powerful for the extraction of arsenate and phosphate ions, but are also useful for liquid-liquid extraction of anions of dibasic acids. It is shown that the high extraction power of these dialkyltin complexes can be explained by formation of innersphere complexes with the extracted anions. A method is proposed for the separation of arsenic, phosphorus and silicon using dialkyltin salts. Applications to the extraction-spectrophotometric determination of phosphorus and arsenic in vanadium and steel, and to extraction/atomic absorption determinations of arsenic and phosphorus in metals and alloys are surveyed. The use of the dialkyltin salts for the neutron activation determination of arsenic and as active components in membranes of ion-selective electrodes for phosphorus(V) and arsenic(V) is demonstrated.