What is indicated by the x-axis in an elution profile?

In an elution profile, the x-axis typically represents the volume of buffer coming off the column. During chromatography, proteins or other compounds are separated as they pass through a column and are gradually eluted with a buffer solution. The volume of the eluent (buffer) that has been collected at each point is plotted along the x-axis against a measure of the quantity of protein (often concentration) on the y-axis.

This setup allows researchers to observe how different components elute from the column over time or buffer volume, giving insight into the separation efficiency and timing of the elution of various proteins. Each peak in the concentration (y-axis) corresponds to a specific protein or molecule that has eluted from the column as a certain volume of buffer has passed through. Understanding this relationship is crucial for interpreting elution profiles in biochemical research.