Interaction of water-soluble vitamins with a new HPLC stationary phase based on zinc phthalocyanate

The adsorption of water-soluble vitamins on the surface of Diaspher-110-C₁₈ sorbent modified with zinc octa-4,5-carboxyphthalocyanate is studied. Adsorption isotherms are constructed and calculated by the Glücauf method at 20°C. It is established that the shape of the isotherms depends on the nature of vitamins and their structure: the isotherm of vitamin C is a Henry-type isotherm, the isotherms of vitamins B₃ and B₆ are of S-type, and the isotherm of vitamin PP-amide is of L-type. Monolayer capacities, adsorption equilibrium constants, and Gibbs energy changes are calculated.