Longer-Lasting TLC Spots Developed with Iodine Vapors on removing the plate from the chamber. We have found asimple way topreserve the originalspot intensity for longer durations hy using the following method. The d a t e s are developed in the iodine chamher in the usual way, which are then covered immediately with a clean glass platiof similar dime&ions in such a way that the silica gel remains undisturbed. Now one can observe the spots through the top plate, and they remain unaltered in intensity over several hours. This allowed us to preserve the TLC plates for sufficient time t o follow up column chromatographic separation and the instructor t o check and verify the student experiments in the laboratory. I
AUthor to whom correspondence should be addressed.
Nitin Maheshwari H. G. ~rlshnarnurty' University 01 Delhi Delhi-110007, India
1066
Journal of Chemical Education
