Final answer:
A compound with a short retention time moves faster through a chromatography column than a compound with a long retention time. Retention time reflects how long a substance interacts with the stationary phase of the column, influencing the speed of elution.
Step-by-step explanation:
Compounds with short retention times move faster through a chromatography column compared to those with long retention times. The retention time is the period a compound spends in the column after the sample is injected. A compound that is less retained will have a shorter path through the column and thus elute, or come out of the column, quicker than a compound that has a higher affinity for the stationary phase and therefore is retained longer.
In dealing with chromatograms, the capacity factor (k') can also provide insight into the relative speeds of compounds moving through the column. This factor is calculated by the relative retention time compared to the void time, which represents the rate at which the solvent moves through the column. The lower the capacity factor, the faster the compound moves relative to the solvent front.
The example provided with Peak A having a retention time of 9.3 minutes and a void time of 2.0 minutes indicates a capacity factor and shows how the substance interacts with the chromatography medium.