Say you have a crystalization dish filled with MeOH containing a few grams of mdma, and 5 feet away you have a little beaker fuming a small amount of bromine. You leave the workspace and return 24 hours later to purple mdma crystals.
My guess is this.. some of bromine fumes made their way to the crystalization dish, discolorng what other wise would have been very pure mdma.
Mistified, the crystals are then washed with acetone/recrystalized 3x, each time resulting in whiter looking crystals, yet still purpleish.
I know that an a/b will solve the problem, but im wondering if im right.. is that likely what happened?