COMBINED ASCENDING DESCENDING PAPER-CHROMATOGRAPHY

The following brief paper describes a modification of paper chromotography that includes both ascending and descending flow using readily available equipment. Advantages of this technique: 1. The time for the run is reduced slightly. 2. Each spot with an Rf greater than 0.50 will have its own channel and can be detected individually. 3. A much longer flow distance is available. Materials needed: 600-mL beaker 10 mL of developing solvent plastic covering and rubber band chromatogram paper (19- x 14-cm) solutions of knowns and unknowns capillary spotter seven polyethylene tubing sections polyethylene clip