The rare-earth element content of GSJ rock reference samples determined by gradient ion chromatography.

Abstract

Eleven of the rare earth elements (lanthanide series) have been determined in fifteen Geological Survey of Japan igneous reference samples by high performance ion chromatography (HPIC). Multiple analysis of each reference sample was undertaken to provide the best possible data. The technique, which employs chelating agents to permit the separation of individual rare-earth elements as anionic complexes, has a reproducibility of <4%. With the use of on-line sample solution concentration, detec tion limits of 0.1 ppb were possible, enabling the satisfactory analysis of rare-earth element impover ished samples such as feldspars JF-1 and JF-2, and peridotite JP-1. The results for the very well character ised sample JB-1 are in close agreement with published recommended values. Whereas our results for JG-1 and thirteen currently available members of the second "Igneous rock series" are generally in broad agreement with published values, in a majority of cases there are significant differences in one or more elements. In each case where significant discrepancy exists, the smooth and highly coherent pat terns of the HPIC data when plotted on chondrite-normalised rare-earth element diagrams, contrasts with the more erratic patterns for the published values, suggesting the likely greater accuracy of the HPIC data.

Tetrad effects and fine structures of REE abundance patterns of granitic and rhyolitic rocks: ICP-AES determinations of REE and Y in eight GSJ reference rocks.

“…Similar deviations of the ICP-MS values by Hirata et al (1988) are also plotted in Fig. Al(B (Watkins and le Roex, 1992) and the MS-ID value for Ho using 163Ho with T112 = 6,000 y (Kawakami and Masuda, 1984) were tentatively used as the reference values. For the Tm data, however, we did not make such cal culations, since we cannot select any acceptable Tm value for JB-1 except for our ICP-AES value and the ICP-MS one by Hirata et al (1988).…”

“…In this context, the HPIC technique (le Roex and Watkins, 1990;Watkins and le Roex, 1992) is not satisfac tory, since Ho, Tm, and Lu data are not reported by their HPIC method due to analytical difficulties caused by the co-elution of Y with Ho and detec tion limits for Tm and Lu. ICP-MS is currently one of the most sensitive techniques to analyze all REE.…”

“…The compilation averages for Er in JG-l and Ho, Er, and Tin in JG-2 may have been in fluenced by the reported values based on analyses with incomplete sample digestions. Watkins and le Roex (1992) reported REE analyses by HPIC for the GSJ reference samples, in which they prepared sample solutions by open digestion with HF plus HC1O4 and then they fused the filtered insoluble residues with KHF2 accord ing to Walsh et al (1981). We have compared our ICP-AES results with their HPIC analyses for evaluating the accuracy of our results.…”

Determination of rare-earth elements in rock samples by an improved high-performance ion chromatography

“…Therefore, the pretreatment of sample using an ion-exchange column is generally carried out in the HPIC/HPLC analysis (Cassidy, 1988;le Roex and Watkins, 1990;Watkins and le Roex, 1992;Asahara et al, 1995;Na et al, 1995). The procedure of matrix removal used in this study is the modified version of the method described in Lee et al (2000).…”

“…The instruments of HPIC/HPLC are currently used in widespread analytical routines in institutes globally, and commercially available at a reasonable cost. Some pioneering studies revealed that the HPIC/HPLC is an excellent means of REE analysis in rock samples (Cassidy, 1988;le Roex and Watkins, 1990;Watkins and le Roex, 1992;Asahara et al, 1995;Na et al, 1995), although some REE (Dy or Ho in all cases and Er, Tm and Lu in individual cases) were not measurable and relatively large sample size (300 to 1000 mg) was generally required in these studies for precise REE analysis. In this paper, we present an improved HPIC technique in which all fourteen REE in rock samples as small as <50 mg can be determined with satisfactory precision and accuracy.…”