between aluminium, glass and plastic plates, which gives best separation in Thin Layer Chromatography?

Answer 1

Basically, there is no difference of separation efficiency among aluminum, glass and plastic plates TLC because all are coating with the same materials such as silica gel, aluminum oxide or C-18.
However, there are some differences in operation among them.
Plastic plate cuts to small pieces easier than the other. Glass plate need a diamond glass cutter to cut it and experience is needed to prevent cutting unevenly or even breaking the glass.
If the spot can only be visualized by spraying and heating, plastic plate may melt during the heating process. Glass plate and aluminum plate do not have this problem.
If a long TLC plate is needed (such as 20cm), a glass plate is better because plastic and aluminum plate will curve in the tank.