Normal Phase Chromatography

The components in a mixture will elute at different rates depending on each one's polarity relative to the next. When the column to be used for the separation is more polar than the mobile phase, the experiment is said to be a normal phase method. In normal phase chromatography, the stationary phase is polar, and so the more polar solutes being separated will adhere more to the stationary adsorbent phase. When the solvent or gradient of solvents is passed through the column, the less polar components will be eluted faster than the more polar ones. The components can then be collected separately, assuming adequate separation was achieved, in order of increasing polarity. This method of chromatography is not unique to liquid-solid column chromatography and is often used when performing High Performance Liquid Chromatography (HPLC). Although HPLC is an example of liquid-liquid chromatography, in which both the stationary and mobile phases are liquid, normal phase elution is achieved by coating the solid adsorbent column with a polar liquid.