Titrimetric and spectrophotometric methods for the determination of cerium(IV) in aqueous solution

A titrimetric and spectrophotometric methods for cerium(IV) determination have worked out. The first method relies upon the treatment of cerium(IV) solution with an excessive amount of iodide; the liberated iodine is extracted into chloroform, then reduced to iodide. The latter is iodometrically determined after 6- or 36-fold amplification. The spectropho-tometric finish is based upon the reaction of the titled ion with iron(II), in the presence of hexacyanoferrate(II), to form an intense prussian blue color suitable for the trace determination of cerium(IV) ion.