The samples are applied onto the plate either as spots or as bands. Precision of the applied volume, exact positioning and compactness of application zone determine the quality of the final result.
The mobile phase is drawn through the stationary phase by capillary action. Samples are separated into their components which remain in their position on the layer after the mobile phase has been evaporated. Chromatography is affected by the gas phase in the chromatographic chamber.
Substances without chromophores or color can be visualized or made detectable through derivatization. The required reagents are transferred onto the chromatogram by spaying or immersion.
The chromatogram is evaluated under white or ultraviolet light. Options range from visual inspection of electronic images to quantitative determinations using scanning densitometry. For documentation electronic images are easy to capture and to archive. They can be reproduced on screen without changes over time and thus compared with current images. TLC-MS and bioluminescence expand the capability of TLC.