Effect of temperature on gradient reequilibration in reversed-phase liquid chromatography.

The effect of mobile phase modifier and temperature on gradient reequilibration is examined using three different stationary phases. The stationary phases studied are a traditional C18 phase, a polar endcapped C18 phase, and an alkyl phase with a polar embedded group. It was observed that both temperature and choice of mobile phase organic modifier had an effect on gradient reequilibration volume on both the traditional C18 stationary phase and the polar endcapped phase. On both these phases, at any given temperature, the reequilibration volume was generally smaller when methanol was used as the mobile phase modifier as compared to acetonitrile. As the temperature is increased from 10 to 50 degrees C, significant reductions in reequilibration volume were observed with both mobile phase modifiers. In contrast, neither temperature nor choice of modifier appeared to have much effect on reequilibration volume when the polar embedded group stationary phase was considered.