Paper Chromatography of Metal Ions in Formic Acid-alcohol Systems: Separation of Tian and Antimony from Numerous Metal Ions

Chromatographic behaviour of 29 common cations has been studied in alcohol-formic acid ratios of 9:1, 7:3, 5:5, 3:7, and 1:9. The plot of R_f value of a metal ion against %formic acid provides an S-shaped curve, the R_f value increasing with increase in the acid concentration.

Sn²⁺ and Sb³⁺ show exceptional behaviour. In butanol-formic acid (1:9), these have R_f values (Sn= 0.50; Sh= 0.62) oven though most metal inns either 'tail' from the 'point of application or have zero R_f valves. This behaviour and other structural effects have been explained in terms of the polarity of the chromato­graphic system.