Overloading Behavior of Anthracyclines on Silica Column with Aqueous-Organic Mobile Phases: Effect of Organic Modifier

Abstract

The peak shapes of 4 anthracyclines have been investigated using isoeluotropic mixtures of acetonitrile, methanol and tetrahydrofuran (THF) in combination with formate buffer at pH 2.9 on a silica column. With aqueous or aqueous-rich mobile phases, no significant differences in overloading behavior have been found with various organic modifiers. With organic-rich mobile phases, peak shape and its dependence on sample size are notably different when organic modifier concentration is changed. Pure aqueous buffer produces the overloaded peak profiles of the solutes associated with a typical Langmuir isotherm, while distinct anti-Langmuirian peaks have been achieved with organic-rich eluents. The general similarity of the loading behavior for the solutes with acetonitrile, THF or isopropanol has been reflected either in aqueous-rich or organic-rich eluents, suggesting that the nature of organic modifier dont dominate the peak shape but water content in the mobile phases.