For the DOX samples the TLC plate was then placed into a beaker containing the mobile phase where the liquid level covered the bottom of the TLC plate such that the upper level of the mobile phase was below the level of the sample spots on the TLC plate. The container was covered to increase the vapor pressure of the solvent in the container and speed the development of the plate. The plate was then run for 30 min until the advancing phase was just below the top of the plate. This covered a distance of approximately 8.5 cm.