Thiomichler's ketone (4,4'-Bis(dimethylamino)thiobenzophenone) can be used as a photometric reagent for the determination of gold, palladium, platinum, mercury, silver, and copper. Thiomichler's ketone is a kind of biological materials or organic compounds that are widely used in life science research[1].
Purify the thioketone by recrystallisation from hot EtOH or by trituration with a small volume of CHCl3, followed by filtration and washing with hot EtOH [Terbell & Wystrade J Phys Chem 68 2110 1964]. Also it recrystallises from CHCl3/ MeOH. [Beilstein 14 H 101, 14 I 395, 14 II 60.]
[1] Bergmeyer H U, et al. Biochemical reagents[M]//Methods of Enzymatic Analysis. Academic Press, 1965: 967-1037.