On the other hand, many plant secondary metabolites are prone to oxidation, and are particularly labile once applied to silica gel TLC plates. Place your plate, origin side down, in the TLC tank or beaker. Replace the cover, and allow the solvent to move up the plates until it is within 0.5 cm of the top. Remove the TLC plate from the tank and dry it with a hair dryer. Take the plate to the darkroom and observe it under long wave and short wave UV light.
Some people find the smell of n-butanol to be somewhat objectionable.
The combination of n-butanol and acetic acid, another common TLC solvent, is particularly pungent. Dry your plate thoroughly in the hood before taking it to the dark room for observation under UV light. Return to the lab and prepare the diazotized p-nitroaniline spray reagent. Swirl the flask to mix. Assemble the sprayer, and lightly spray the plate with the spray reagent.