P 2227 (OTTO) Potassium ferricyanide, GR 99%+ Cas 13746-66-2 - used to determine dopamine hydrochloride levels. P 2227 (OTTO) Potassium ferricyanide, GR 99%+ Cas 13746-66-2 - used to determine the ferric reducing power potential of a sample (extract, chemical compound, etc.).