The determination of rare earth elements in marine sediments by ion-exchange separation and ICP emission spectrometry

A method has been developed to measure rare-earth elements (REE) in gram-sized marine sediment samples. A strong acid digestion technique followed by ion-exchange chromatography is used to solubilize, separate, and purify the REE from other matrix components. Instrumental detection is by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Excellent precision and accuracy were proved by analyses of unknown sediment replicates and standard reference rock samples. Blanks and empirically determined detection limits are discussed in relation to measured REE concentrations in sediments. Direct evidence is given for the co-precipitation and fractionation of the REE by precipitates formed as a result of the acid digestion with HF. A technique for dissolving these is then presented.Funding was provided by the National Science Foundation under grant Number OCE 84-17910; and the United States Department of Energy under grant Number DE-AC02-76EV03566