Selection of Stationary Phase and Mobile Phase in High Performance Liquid Chromatography

Abstract

Selection of ideal mobile phase and stationary phase is very important to get accurate separation of mixtures or impurities as a whole. There indeed are parameters which are explained in this article, important to be kept in mind while a method development of HPLC method. But as such there is no list of such parameters and their accurate limits can be applied while method development. In this article, there have been mention of certain parameters which are generally looked for, and not exact, but optimal application of such has been discussed. When we talk about stationary phase, parameters which we tend to optimize very often include mostly commonly the pH of the analyte as well the mobile phase used and stability of the column packing material over a range of temperature. Choosing of stationary phase greatly depends on the nature of analyte. Stationary phase will depend and vary simultaneously if analyte is lipophilic or an ionic compound. In order to increase separation and increase mass transfer there have been new addition to column packing material apart from the widely used silica. New advances result into greater column loading, better flow, reduced plate height and reduced back pressure. Leaving alone stationary phase, mobile phase selection is also a task of its own. Very commonly used mobile phase solvents include acetonitrile, methanol, THF, water and buffer of salts like acetate, phosphate, etc. Apart from these traditional choices, there have been use of pressurized hot water and ionic liquids as mobile phases which are termed as “Environmental-friendly” because these solvents are devoid of any organic counterpart or organic modifier in them, which produces harmful fumes on getting heated. Apart from the environmentally friendly mobile phase options, we have some specific chemicals to be used when chemical property of the analyte is specific.