Indirect Atomic-Absorption Spectrometric Methods of Analysis

Abstract

The direct determination of certain metals is impractical because of oxide formation in the use of flame atomizers, and the direct determination of nonmetals is often not feasible because either a suitable source of incident radiant energy is unavailable or the absorption lines are in the vacuum-ultraviolet region. Indirect methods are being developed to circumvent some of these difficulties. The general technique involves the formation of a complex consisting of the desired constituent and a metal which can be determined directly by atomic-absorption spectrometry. It is important that the ratio of desired constituent to metal be stoichiometric and it is advantageous if this complex is extractable from aqueous solution with an immiscible organic solvent. Specific indirect methods for germanium, phosphorus, silicon, nitrate, thiocyanate, etc., will be discussed.