Nine basaltic rocks from the New Georgia Group, the Solomon Islands, have been analyzed for REE, Ba and Sr abundances, Sr and Nd isotopic ratios, and major element compositions. Nd and Sr isotopic ratios of four olivine basalts and two picrite basalts fall in restricted ranges, suggesting that these rocks have a common source. REE patterns of six of these basaltic rocks have the following features: (1) The patterns have no intersection with each other, (2) All of the patterns possess a common fine structure of convex curve around Nd-Gd-Dy, and (3) Inclination of light REE span increases with increase of REE concentration. REE pattern analysis of the basalts leads to inferences that (A) a linear REE partition coefficient function with a sharp break at Ho has operated in the generation of the olivine basalts by the Rayleigh fractional crystallization of a picrite basalt magma, and (B) the absolute magnitudes of the partition coefficients did not change substantially during the magmatic differentiation.
Abstract An on-line separation-detection system, liquid chromatography coupled with inductively coupled plasma mass spectrometry (ICP-MS), has been developed and applied to the study on speciation of trace metals in pond water. First, the total concentrations of dissolved metal ions in pond water were determined by ICP-MS after chelating resin preconcentration. Then, pond water was preconcentrated by ultrafiltration using a filter with a molecular weight permeation limit of 10000, providing size exclusion chromatography. Large organic molecules which had combined with trace metals in the preconcentrated samples were separated with a gel filtration column and detected by UV absorption and ICP-MS, sequentially. In consequence, large organic molecules with the molecular weight of ≥300000 and 10000—50000 could be observed. A large number of trace metals (41 elements) were found in those organic molecules. Furthermore, the percentages of metal ions in the forms of large organic molecule–metal complexes were estimated from their concentrations as determined by the flow injection method.
Abstract Rare earth elements in coastal seawater were preconcentrated by using chelating resin in a batch method and determined simultaneously by inductively coupled plasma mass spectrometry (ICP-MS). In this procedure, matrix components (Na, K, Mg, and Ca) were eliminated to reduce matrix effects in ICP-MS analysis and rare earth elements were concentrated by a concentration factor of 100. The pH dependence of the recovery, resin amounts, amount of ammonium acetate for washing, and elution of adsorbed metals with nitric acid were examined in details to optimize the experimental conditions in sample pretreatment. All rare earth elements in coastal seawater were determined at the ppt or sub-ppt level successfully by the present analytical method.
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