Abstract
A spectrographic method was studied to determine simultaneously microamounts of calcium and magnesium in cast iron. A sample were dissolved with acid, iron was removed by methyl-isobutyl-ketone extraction, then the solution containing calcium and magnesium was put in a porous-cup electrode and the spectra was excited with a condensed spark. Strontium and beryllium were added as the internal standard elements for calcium and magnesium, respectively, and Sr II 4215.52A/Ca II 3933.67A and Be II 3130.42A/Mg II 2802.70A were used as analytical line pairs. This method was applicable to the determination of calcium and magnesium in concentration above 0.005 per cent and the variation coefficients were 13.5 per cent for calcium and 9.7 per cent for magnesium at a concentration level of 0.01 per cent.
