Baseline

Each sample starts at a separate position on the baseline, so read the spots above that position as one lane. Under suitable conditions, a pure substance gives one spot; a mixture of substances that separate gives more than one. One spot alone cannot guarantee purity: two substances might travel together and appear as a single spot.

Each sample begins as a small spot on a baseline. As the mobile phase moves through the stationary phase, the substances in a sample may travel different distances and form separate spots.