Improved capillary electrophoresis method for measuring rare-earth elements in synthetic geochemical standards

An improved capillary electrophoresis (CE) method for quantifying rare-eart h elements (REEs) in synthetic geochemical standards was developed. Synthet ic standard solutions were obtained from high purity metal oxides. The sepa ration of REE total group (lanthanum to lutetium) was defined as a primary objective. Special attention was also focused on the optimized separation o f europium (Eu) and gadolinium (Gd) because in earlier applications they pr esented overlapping problems. Their separation and quantitative determinati ons are essential for geological applications. For the rapid separation of REEs in synthetic geochemical standards, the temperature of the separation device was optimized. An analysis temperature of 15 degrees C enabled both the rapid separation of REEs within 2 min and the overlapping problem of Eu -Gd to be resolved. The detection limits (<0.1 ng) and precision estimates (generally better than 5%) were found to be satisfactory for most geologica l applications. (C) 2000 Elsevier Science B.V. All rights reserved.