Cobalt Analysis by Automated Photometric Titration

Like nickel, cobalt in the Earth's crust is found only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. Cobalt can be analyzed in aqueous solutions by direct titration with EDTA at pH 9. The indicator is murexide, and the equivalence point is determined with the Optrode at a wavelength of 574 nm.