Figure 21 : Inserting the mobile phase system directly without any pre run is OK only in case the wick is still dry and the mobile phase is not a mix of several solvents. If the task shown above means: cleaning the plate by methanol it is OK to insert the phase bottle this way. Note the four small glase plates in the cover glass corners. Inserting a mobile phase bottle is acceptable only when a virtual gas chamber exists. Not shown here: A 1 mm virtual gas chamber can also be made using a 1 mm o.d. PTFE tube circle, however the circle must be closed (a 0.2 mm o.d. steel wire piece does it in case the PTFE tube has the dimensions 1 x 0.2 mm and a circle diameter of about 90 mm..