Figure 8 : Ready made TLC / HPTLC plates are NOT ready for analysis. Theyneed a clean up by strong eluting (clean) mobile phases free from non volatile impurities. On silica plates also the water content is important and must have an optimal concentration. Absolutely water free stationary phases do not offer qualified chromatography at most of the analytical applications. The best final procedure is a gas phase treatment with gas containing all the traces for an optimal separation. Besides a certain amount of water these may be volatile acids, bases or highly polar traces.