Sensitive reagent for several heavy metals, Co, Cu, Pb, and Hg; especially for the estimation of minute amounts of Pb.
Dithizone is an organosulfur compound that acts as a chelating agent and forms complexes with metals such as lead and mercury. Dithizone is used to assess the purity of human pancreatic islet preparations used for transplantation into patients with type 1 diabetes.
The crude dithizone is dissolved in CCl4 to give a concentrated solution. This is filtered through a sintered glass funnel and shaken with 0.8M aqueous ammonia to extract dithizonate ion. The aqueous layer is washed with several portions of CCl4 to remove undesirable materials. The aqueous layer is acidified with dilute H2SO4 to precipitate pure dithizone. This is dried in a vacuum. When only small amounts of dithizone are required, purification by paper chromatography is convenient. [Cooper & Hibbits J Am Chem Soc 75 5084 1933.] Instead of CCl4, CHCl3 can be used, and the final extract, after washing with water, can be evaporated in air at 40-50o and dried in a desiccator. It complexes with Cd, Hg, Ni and Zn. [Beilstein 16 H 26, 16 IV 18.]
dark brown or black crystals