The solubility parameter as a tool in understanding liquid chromatography

Summary The solubility parameter concept is briefly discussed. It is then used to explain some of the current features of liquid partition and adsorption chromatography. Various phase systems are discussed on the basis of three characteristics.retention, selectivity (the general separation power of a system) andspecificity (increased separation power towards certain pairs of solutes). The emergence of two essentially different techniques, the normal phase and reversed phase modes, will appear as a logical consequence of simplified theory. It also becomes obvious why reversed phase applications are so much more numerous. Some suggestions are given for the development of new stationary phases and the improvement of existing ones. The usefulness of the solubility parameter concept to predict the solvent strength of mixed eluents in reversed phase liquid chromatography (RPLC) is demonstrated. Some practical rules for the selection and operation of stationary and mobile phase systems are formulated.Main author.