HPLC is particularly suitable for analyzing substances that are not so volatile or non-volatile, ionic, thermally unstable, easily broken down as well as substances with a high polarity and a high molecular weight.
In HPLC the sample is separated into its component parts (analytes) as a result of the difference in the relative affinities of different molecules for the mobile phase (eluent) and the stationary phase (column) used in the separation. As the sample passes through the column it interacts between these two phases at different rate, primarily due to different polarities in the analytes. Analytes that have the least amount of interaction with the stationary phase or the most amount of interaction with the mobile phase will exit the column faster. As each component leaves or elutes from the column, a detector will give a response that is proportional to the concentration of the component. The time to elute from the column (retention time) for a component will be very specific for a given set of chromatographic conditions and may be compared with that of a standard for identification.
HPLC is one of the most widely used analytical techniques, the other being gas chromatography, by our laboratory.
