The spectrophotometric determination of alkaline earth metals after separation by paper chromatography

The spectrophotometric titration of magnesium, calcium, strontium, and barium, in the visible and ultra-violet regions of the spectrum, has been investigated and a method is presented for the determination of small amounts of these elements by spectrophotometric titration using Eriochrome Black T as indicator, after separation by paper chromatography and removal from the paper with dilute hydrochloric acid. The minimum amount of each cation determined was 0.5 μ M and the procedure was applied successfully to the analysis of a dolomite, a strontianite, and a barytocalcite.