5% HAuCl4 in 1:2 concentrated H2SO4: H2O
In the acidic gold chloride reagent, ethcathinone at amounts greater than 20 μg slowly forms yellow, flat straw-like crystals. The crystals grow either individually or in clusters.
Platinic Bromide (H2PtBr6)
Platinic bromide is the best reagent for ethcathinone giving reproducible and distinct sheaves and dendrites of red needles. With time, the crystal formation covers the entire drop. Amount of ethcathinone needed is lower than 20 μg and crystal formation time is much faster than the acidic gold chloride reagent.