Flash Chromatography is characterised by sample sizes from a few mg to 100s of grammes.

The most common column packing material is normal phase silica, used with non-polar solvents. Flow rates may be from 10ml/min to upwards of 300ml/min.

Increasingly, Reverse Phase packings are being used with polar solvents. In this case, the separation is closer to reverse phase HPLC and has no relationship with TLC. The resolution is a lot lower than HPLC and so the sample compexity must be less to obtain a good separation.

For the purposes of this introduction, we will assume normal phase chromatography.