DETERMINATION OF RARE-EARTH ELEMENTS IN URINARY CALCULI BY ICP-MS

Rare earth elements (REEs) were determined in urinary calculi by induc tively coupled plasma mass spectrometry (ICP-MS). ICP-MS was chosen be cause, unlike instrumental neutron activation analysis (INAA), it is a technique that can be developed in routine laboratories. Fourteen REE s were determined in eight urinary calculi of three different types (o xalates, phosphates, and mates). Urinary calculi were dissolved by a p rocess of acid digestion that permitted the quantitative recovery of R EEs in any kind of matrix. A column ionic exchange method was applied for the separation of majoritary elements in the case of phosphate mat rix. Validation of the method was done by the standard addition method .