Normal Phase Chromatography

Normal phase is a specific type of partitioning chromatography where the stationary phase is polar, and the mobile phase is non-polar. While the compounds selected might not be particularly polar or non-polar, their relative polarities are the most important. As long as the stationary phase is more polar than the mobile phase, it is considered normal phase chromatography. The stationary phase is usually a column packed with silica particles that have R groups attached. Common R groups for normal phase are -C₂H₄CN or -C₃H₆NH₂.

When the mixture passes through the column, the polar components will be more attracted to the stationary phase and the non-polar components will be attracted to the mobile phase. This will lead the non-polar components to flow through (or elute) the column first. The more polar a compound is, the longer it will take to elute. By increasing the polarity of the mobile phase, the bound polar component will partition more into the mobile phase and elute from the column.