General method for analysis of siliceous materials by atomic-absorption spectrophotometry and its application to macro- and micro-samples

Abstract

The method described can be used for the dissolution and determination of major and minor constituents in a wide range of compositions of siliceous materials. A pressure dissolution vessel is used for fast and complete acid attack. The principle solvent is hydrofluoric acid, but boric acid is added after dissolution to complex excess of hydrofluoric acid and dissolve precipitated fluorides. A second heating step is shown greatly to improve the efficiency of this process.Most inter-element interferences are removed in the presence of the fluoroboric acid so formed when the dinitrogen oxide-acetylene flame is used. Neither releasing agents such as lanthanum nor detailed matching of standards to sample compositions are therefore necessary. Both macro- and micro-scale versions of the method are given, the latter having proved satisfactory for samples as small as 10 mg, such as those commonly encountered in archaeological work.