LIQUID-CHROMATOGRAPHIC SEPARATION OF POLAR ORGANIC-COMPOUNDS USING STRONG ANION-EXCHANGER AS THE STATIONARY-PHASE AND PURE WATER AS THE MOBILE-PHASE

A unique high performance liquid chromatographic system for the separa tion of polar organic compounds is described. Strong anion-exchanger w as used as the stationary phase and pure water was used as the mobile phase. When the strong anion-exchanger was conditioned with pure water as the mobile phase, the fixed ionic site with its counterion functio ned as a zwitterionic stationary phase. This facilitated the separatio n of the polar organic compounds without need for ionization of the an alytes. A strong commercial anion-exchanger (polyacrylate-based type) and a laboratory-made one (ODS-based type; obtained by dynamically coa ting hexadecyltrimethylammonium salts on the reversed-phase ODS surfac es) mere chosen to represent the stationary phases. Five purine and py rimidine bases and eight nucleosides were chosen to represent the pola r organic analytes. All of these polar organic analytes were successfu lly separated and rapidly eluted with pure water as the mobile phase. Separation mechanisms involved were investigated and the experimental results suggested that electrostatic interaction was the main mechanis m for separation in polyacrylate-based stationary phase; while, electr ostatic and hydrophobic interactions were dual mechanisms for separati on in ODS-based stationary phase.