Using a pen instead of a pencil to draw a start line might cause this as the ink can travel with the solvent system on the TLC plate.

You may see irreproducible results if you reuse the solvent system for several TLCs.

If the level of the solvent system in the chamber is above the spot when the plate is inserted, the compound from the spot will dissolve in the solvent instead of migrating up the plate.

The level of the solvent system is too high.

There is no compound in the sample due to experimental failure.

The development method needs to be changed.

You can overcome this problem by spotting the sample multiple times in the same place on the slide (allowing the solvent to dry in between applications). The concentration/quantity of the sample is too low.The slurry/silica on the slide has fallen off.The plate touches the sides of the container/chamber/filter paper. The thickness of the TLC slurry is uneven (usually seen when the TLC plate is prepared on a glass slide).

Some of the common problems faced during TLC and their solutions are listed below: Solvent Front Runs Unevenly/Crookedly For this reason, it is important to be familiar with troubleshooting thin layer chromatography. The whole TLC technique sounds easy to do, but it can be difficult and tricky during interpretation or give unexpected results, especially when working with biomolecules.

Tlc results