CHAPTER 39 - Strontium

Abstract

For the determination of strontium in silicate and other rocks, flame photometric and atomic absorption techniques have displaced both photometric and gravimetric procedures. In common with calcium and barium, strontium has a very characteristic flame emission. The strongest emission of strontium is at the resonance line of 460.7 nm. In the determination of strontium by flame photometry, all separations other than that of silica are avoided and the determination is made by adding a standard solution of strontium to separate the aliquots of the rock solution. The depressing effect of aluminum and other elements is masked by the addition of a considerable excess of calcium to the rock solution. Silica is removed by evaporation with hydrofluoric and perchloric acids. This chapter discusses the determination of strontium in silicate rocks by atomic absorption spectrometry (AAS). Most of the standard methods for the decomposition of silicate rocks are used in the preparation of the rock solution for strontium determination. These include fusion with alkali carbonate and lithium borate as well as evaporation with acid mixtures containing hydrofluoric acid.