English Abstract The estimated concentrations of the rare earth elements
(REE) in drinking water vary between 0.3 ng/l for Lu and 130 ng/l for Ce.
Sc, Y, La, Ce and Eu may be determined without preconcentration ; the other
REE need a 50-100x preconcentration. This report describes several off-line
preconcentration methods like precipitation, extraction and column
chromatography. On-line preconcentration with an automated extraction
system offers advantages like quick sample analysis (about 4 min), minimal
sample handling and minimal contamination. The REE determination by ICP-MS
suffers from REE oxide spectral interferences. These oxide levels can be
minimized by optimizing the instrumental parameters. The best isotope
choice is: 45Sc, 89Y, 139La, 140Ce, 141Pr, 143Nd, 147Sm or 149Sm, 151Eu,
157Gd, 159Tb, 163Dy, 165Ho, 167Er, 169Tm, 171Yb and 175Lu. 115In can be
used as an internal standard for sensitivity, 248ThO/232Th can be used as an
internal standard for the MO/M ratio. Gaussian correction formulas or
principal components analysis (PCA) should be used, if the REE oxide
interferences cannot be reduced sufficiently.