Figure 37 Simultaneous multi phase chromatography. Into the plate center one sample isgiven and focussed to a circle with a diameter as large as the outer border of four wick tubes. Four differing mobile phases are already in flow equilibrium an a waste plate. The cover glass with all four mobile phase bottles is moved quickly and exactly onto HPTLC plate. If wanted, it can be have a size of 100 x 100 mm or 100 x 200 mm. The multi phase chromatogram is dried by flash gas through a single hole cover glass plate and qualitatively analyzed by multi integration at 8 positions: at the 100% phase A, B, C. D and in the middle of neighbored phases. There we have a mobile phase composition if 50% A with 50% B, 50% B with 50% C an so on. Traces of A in B are at about 95% of the B phase with 5% of the A phase. This procedure the author already showed - but only by pictures - in the first HPTLC book, click here. You find the promising results on pages 193-197 but only with three phases simultaneously.