Determination of rare earth elements in gadolinium-based contrast agents by ICP-MS.

A simple ICP-MS procedure for the determination of trace element concentrations in GBCAs is described here. Abundances of most of the REEs, Y, Ba and Pb concentrations were determined. We confirm that GBCAs contain traces of non-Gd REEs, Y, Ba and Pb. REE patterns of the five GBCAs actually administered in France have been obtained. They display specific shapes that make it possible to identify the different Gd oxides oxides used by pharmaceutical laboratories to produce them. Our method enables us to quickly evaluate the quantities of impurities in these products and, if necessary, to follow the evolution of their quality in the future. The presence of small but not negligible quantities of Y and REEs other than Gd cannot be ignored in these products, and their behaviour in the human body must be considered. The concentrations measured for Pb and Ba, on the other hand, are much lower and do not pose any particular problems.