Distribution coefficient measurement, elution behaviour and column separation of some cationic dyes on chemically pretreated stannic oxide

The distribution coefficients K_d of three cationic dyes (methyl violet 6B, phenosafranine and Janus Red) on hydrated stannic oxide with a surface phase pH of 6.0–11.0 were determined at dye concentrations of 20 x 10⁵, 100 x 10⁵ and 180 x 10⁵ mol 1^-1 at 30 ± 1 °C for a contact period of 24 h. Elution studies of the dyes on some of the substrates (pH 7.0–8.5) were conducted using inorganic electrolytes (barium nitrate and aluminum nitrate (0.1 M–1.0 M) and ethanol. On the basis of the K_d values and the elution behaviour, some binary separations of the dyes on a column were achieved. The study shows the usefulness of chemical pretreatment of hydrated oxides, such as stannic oxide, in chromatography.