Separation of steroid mixtures by time‐optimized thin layer chromatography

Separation of complex mixtures by parallel development thin-layer chromatography

“…From this it follows that the rate of migration of any spot will be Rf(n/2l). Thus the distance d2 is d2 = Rf(K/2l)t2 (6) tx, the time for the solvent front to traverse the plate length l is tl = l2 / (7) Rearranging eq 1 it follows that h = ti ~l2/K (8) and (9) Rf can be expressed as a function of capacity factor and mole fraction (eq 5 and 4). From this and eq 2, it follows that 1 l2 -2lx+ nt[ 1 = 1 + exp (a In Xs + b) [ 21 J (10) For the sake of brevity, several steps in the derivation of eq 10 are not included but will be described elsewhere.…”

“…Thus the utility of a diagram such as Figure 1 is for sorting compounds into sets, rather than for defining optimum chromatographic conditions. The method of selecting optimum conditions for the TLC separation of a mixture of compounds in a minimum time has recently been described (9). Familiarity with the method is assumed in the ensuing discussion.…”