[Cantacoxinha]

I'm looking for a TLC stain suitable for detection of alkyl-bromides (e.g. butyl-bromide, hexyl-bromide, isobutyl bromide etc.). Is there any?

[TheUnassuming]

KMNO4 is a good place to start.

[discodermolide]

Taken from Dyeing Reagents for Thin-Layer and Paper Chromatography. You may need to Google it to get a PDF:

This is for chlorinated hydrocarbons, but will work just as well for brominated ones:
Silver nitrate - hydrogen peroxide for chlorinated hydrocarbons.
Spray solution: Dissolve 0.1 g silver nitrate in 1 ml water, add 10 ml ethylene glycol monophenyl ether, fill up to 200 ml with acetone and add 1 drop 30% hydrogen peroxide.
After-treatment: Irradiate with unfiltered UV light. If long-wave UV light is used expose alumina layers about 50 min and silica gel layers up to 15 min. Dark spots are formed.

M.F. Kovacs, J. Assoc. Off. Agr. Chemists 46, 884 (1963).