A method for the determination of lathanum, praseodymium, neodymium and samarium oxides in cerium dioxide has been developed.
The sample in the oxalate form is mixed with the binding material (boric acid) in the ratio 1∶1 pressed to form a double layer
pellet over a boric acid backing pellet and irradiated by X-rays from a tungsten tube. The secondary X-rays are dispersed
with a LiF (200) crystal in a Philips PW 1220 semiautomatic X-ray fluorescence spectrometer. The intensity of fluorescent
X-rays is measured by a flow proportional counter. The minimum determination limit is 0.01% for lanthanum and samarium oxides
and 0.02% for praseodymium and neodymium oxides. The precision at each concentration of the standards and theoretical minimum
determination limit for each element have been calculated.