Determination of eight lanthanides in apatites by ICP-AES, XRF, and NAA

In the present work eight rare-earth elements (REEs), Hf, and Th were deter mined in eight apatite samples from San Luis, Argentina. The determinations were carried out by three methods: inductively coupled argon plasma atomic emission spectrometry (ICP-AES), neutron activation analysis (NAA), and X- ray fluorescence spectrometry (XRF). A new support for a small amount of sa mple was employed in the determination of La, Ce, and Nd by using XRF techn ique. The same procedure has proved reliable for the determination of major elements by using small amounts of apatite samples. For the ICP-AES determ ination, a group separation of the REEs from accompanying elements was requ ired. This was achieved by ion- exchange chromatography and sequential acid elution. For the determination by NAA, a nondestructive instrumental techn ique (thermal neutron activation) was applied. Conditions of irradiation, d ecay, and measurements for the determination are described. Good correlatio n is obtained by these three methods.