Mobile Phases in Liquid Column Chromatography:
Several physical and chemical properties govern the choice of mobile phases. The most significant factor is the influence of the mobile phase on the selectivity of the system. The solubility of the samples and influence of like as properties as surface tension and viscosity are also important. Solubility of a few samples, especially polymers, limits the selection of the mobile phase and the use of certain detectors imposes constrains.
The choice of mobile phase in liquid column chromatography is all significant. If water-deactivated silica is used as an adsorbent, a solvent is then varied to provide k´ values in the optimum range (1< k´ <10). Solvent strength, that controls the k´ values of all sample bands, is simply predicted in liquid-solid column chromatography. It could be defined quantitatively through the solvent strength parameter εo that are listed for various pure solvents within Table 5.1. Those values are for alumina as an adsorbent. A solvents listed inside Table 5.1 are arranged in sequence of increasing strengths that is referred to as an elutropic series. If an initial solvent is stronger than a weaker solvent is substituted. Same, if the initial solvent is too weak then a stronger solvent is substituted. Thus, an elutropic series can be used to find out right solvent strength by a rapid trial-and-error approach.