REVERSED-PHASE HPLC RETENTION OF DEOXYRIBONUCLEOSIDES AS A FUNCTION OF MOBILE-PHASE COMPOSITION

Comparison of approaches describing retention of deoxynucleosides (dCy d, dUrd, dGuo, dThd, and dAdo) as a function of the mobile phase compo sition has been performed. The volume fraction (F) of organic modifier was changed from 0.05 to 0.30, and to 0.12 for methanol and acetonitr ile, respectively. Linear regression has been carried out for the foll owing equations: log k' = log k'(w) - S X F (1), log k' = H + Klog(1/F ) (2), k' = A + B(1/F) (3), where k' is capacity factor, and log k'(w) , S, H, K, A and B are experimental coefficients. The best fits mere o btained for the eqns. (1) and (3), and the poorest correlations were o btained for eqn. (2). The Slope ratios B-methanol/B-acetonitrile and S -acetonitrile/S-methanol are changed in comparatively narrow ranges wi th average values of 2.86 and 2.30, respectively. Unlike the slope S o f eqn. (1), the slope B of eqn. (3) can characterize the properties of solute and organic modifier simultaneously. For each solute, the inte rcepts A calculated for acetonitrile and methanol as organic modifiers are coincident closely. It is shown the validity of the coefficients of eqn. (3) to express the deoxyribonucleoside properties.