Cerimetry or cerimetric titration, also known as cerate oximetry, is a method of volumetric chemical analysis developed by Ion Atanasiu.
It is a redox titration in which an iron(II)–1,10-phenanthroline complex (ferroin) color change indicates the end point.
The use of cerium(IV) salts as reagents for volumetric analysis was first proposed in the middle of 19th century, but systematic studies did not start until about 70 years later.
For the case of oxidation, a precise excess of high-purity crystalline Mohr's salt is added upon the oxide digestion in aqueous hydrogen chloride (HCl), while for the case of reduction, an excess of 1 M iron trichloride (FeCl3) is added.
In the second- and third-row transition metals, only the early elements would be suitable for the titration, and the limiting oxidation states are Zr4+, Nb5+, Mo4+, Hf4+, Ta5+, and W6+.