The quantitative separation of calcium from magnesium,aluminium and other elements by cation-exchange chromatography in ethanol-hydrochloric acid

Magnesium can be separated from calcium by elution with 3.0 M hydrochloric acid containing 60% ethanol from a column of AG₅₀W-X8 cation-exchange resin. Calcium is retained and can be eluted with 3.0 M hydrochloric acid or 2.0 M nitric acid. The separation factor of (α_Mg^ca=5.6 is considerably higher than that in aqueous hydrochloric acid and comparable to those obtained with organic complexing reagents. Separations are sharp and quantitative; up to 10 mmol of magnesium can be separated from 0.01 mmol of calcium and vice versa on a 60-ml column. Al, Fe(III), Mn, Ni(II), Co(II), Zn, Cd, Cu(II), Pb(II), U(VI), Be, Ga, Ti(IV) in the presence of H₂O₂ and many other elements accompany magnesium and can be separated from calcium quantitatively. Sr, Ba, Zr, Hf, Th, Sc, La and the rare earths are retained together with Ca, but can be separated by other methods.