Effect on separation of injecting samples in a solvent different from the mobile phase

The separation of compounds possessing low solubility in the mobile phase could be improved by applying stronger solvents for dissolving the feed. A model system has been investigated with ethanol–water as the mobile phase, Chirobiotic T as the stationary phase and d,l-threonine as the sample dissolved in pure water. The adsorption isotherms of d,l-threonine were determined as a function of the water content by means of a peak fitting method. Optimal injection conditions of elution chromatography were determined by process simulation. Finally, the optima obtained were verified with experimental data.