Beeinflussung der trennung von purinen und pyrimidinen an sephadex G-10

Abstract

Factors which influence the separation of purine and pyrimidine compounds on Sephadex G-10Sephadex adsorption chromatography can be used for separating pyrimidine and purine compounds. The separation is affected by a number of conditions. This paper describes the variation of temperature, ionic strength, pH, degree of crosslinking, concentration of n-propanol, dioxna and urea, and their influence on the adsorption behaviour of compounds.The degree of adsorption decreases with increasing temperature. Theis relationship is valid for gel—solid interactions. The enthalpy values (δH°) for hypoxanthine and adenosine are −2.35 and –1.92 kcal/mol, respectively, and suggest the existence of hydrogen bonding between the compounds and the gel. For purine and pyrimidine compounds different mechanisms of separatio exist as a result of different δH° values. For the most of the compounds examined the basic heterocyclic nitrogen atoms are the primary sites of adsorption. Therefore, hydrogen bonding between the unshared pairs of electrons of the heterocyclic nitrogen atoms and the hydroxy group or the oxygen of the gel matrix is discussed.Dioxan n-propanol and urea decrease the degree of adsorption, while an increase in ionic strength increases the adsorption. Elution values of compounds correspond to their degree of dissociation.The adsorption chromatography of heterocyclic compounds on Sephadex gels is a useful technique for the separation of mixtures of compounds of synthetic or biological origin. A detailed paper on the chromatographic behaviour and chemical structure is published18.