THIN-LAYER CHROMATOGRAPHIC SEPARATIONS BY CONVENTIONAL GLASS BACKED PLATES AND EMPORE SHEETS - A COMPARATIVE-STUDY

A comparison of separations using conventional TLC plates and Empore sheets is presented. The results show that in certain cases the Empore sheets failed to reproduce the separations obtained using silica gel plates, however, the retention times were comparable. The reversed phase C-18 Empore sheets were found to: (a) require much longer development times than C-18 TLC plates; (b) small increases in water content in the mobile phase (2%) contributed to considerable increase in development time; and (c) the maximum recommended percent water (v/v) in the mobile phase for meaningful and acceptable experimental time should not exceed 20%. It was observed that the Empore sheets were easier to spot than the TLC plates but harder to write on. Day-to-day and experiment to experiment R(f) reproductibility of Empore sheets was better than 5%.