Round-Robin Interlaboratory Study on Rare-Earth Elements in U.S.-Based Geologic Materials

In a study funded by the U.S. Department of Energy (DOE) National Technology Laboratory (NETL), University North Dakota (UND) and Environmental Research Center (EERC) performed first-of-its-kind round-robin interlaboratory (RRIS) to determine lab-to-lab method-to-method variability in analyzing rare earth element (REE) content domestic resources. Analyses REEs on eleven different materials were accomplished laboratories using four procedures: ASTM D6357 (Procedure A), D4503 B), an alternate in-house procedure for digestion REE analysis C), neutron activation (NAA). The results RRIS suggest that NAA is most accurate reliable method many these types materials; however, limited it able determining only ten sixteen REEs. Five seven labs reporting data Procedure A three five B showed excellent performance terms repeatability, reproducibility, agreement with NAA, SRM recoveries based AOAC International guidelines performance. This indicates when strictly followed methods are suitable determination materials, although subject overall capabilities experience individual laboratories.