首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 78 毫秒
1.
The oxidation states of chromium in GSJ JSO-2 (artificially contaminated soil) and three other geochemical reference materials (GSJ JSO-1, JLS-1 and JMS-1) were observed using X-ray near edge structure (XANES). For comparison, other artificially contaminated soil materials (mimic-JSO-2) were prepared by adding Cr(VI) into JSO-1. Their oxidation states of chromium were determined using XANES. The chromium contents were 1118 μg g-1 for JSO-2, 1352 μg g-1 for mimic-JSO-2 and 69-113 μg g-1 for the other reference materials. Most chromium was present as hexavalent in mimic-JSO-2. No hexavalent species were detected in other samples. These results for chromium oxidation state in JSO-2 and mimic-JSO-2 obtained with XANES resembled those obtained from a chemical extraction method. The present JSO-2 has no trace of Cr(VI), although Cr(VI) was added as a major species during preparation. On the other hand, the content of Cr(VI) obtained in mimic-JSO-2 agreed with the original Cr(VI) content. A time-elapse study showed that Cr(VI) contents in mimic-JSO-2 decreased gradually to 70% of the original abundance during 240-day preservation in dry conditions. Moreover, the abundance of Cr(VI) decreased markedly to 15% after 240 days in the wet mimic-JSO-2 containing 20% m/m of water. These experiments suggested that soil humidity enhanced the reduction of Cr(VI) and that Cr(VI) was reduced even in dry conditions. Consequently, it is reasonable to infer that Cr(VI) doped into JSO-2 was completely reduced to Cr(III) during the preservation period of 5 years. The certification of the long-term stability of the chemical form in reference materials will be much more important in future.  相似文献   

2.
Three new rock reference samples, Rhyolite JR-3, Gabbro JGb-2 and Hornblendite JH-1 have been prepared by the Geological Survey of Japan for collaborative studies on their chemical composition. Twenty-eight major, minor and trace elements were determined and presented. The results of homogeneity tests showed that all elements are considered to be distributed homogeneously in each reference sample. Geological and mineralogical characteristics are also described.  相似文献   

3.
  相似文献   

4.
Two new geochemical reference materials, copper ore JCu-1 and zinc ore JZn-1 have been prepared by the Geological Survey of Japan (GSJ) for the determination of major and minor elements and isotopic compositions. JCu-1 is a sample of Cu-bearing sulfide ore typical of the Kamaishi mine in Iwate Prefecture, Japan, and is composed mainly of hedenbergite, chalcopyrite, quartz and calcite. Pyrrhotite, magnetite and actinolitic amphibole were also commonly found. The Zn-rich ore, JZn-1 is a crude ore from the Kamioka Pb-Zn mine in Gifu Prefecture, Japan. The sample consists of hedenbergite, quartz, calcite, sphalerite and epidote as main crystalline phase. Homogeneity test results showed that all studied constituents including ore elements such as Cu, Pb and Zn can be considered to be homogeneously distributed. Provisional collaborative analyses were carried out in ten laboratories, and the data were evaluated using a robust statistical method using z-scores. Recommended values for a number of major elements including TiO2, Al2O3, MnO, MgO, CaO, Na2O, K2O, Fe (total), Zn, Cu and Pb were established. In addition, information values for eighteen major, minor and trace elements are presented to support future collaborative analyses.  相似文献   

5.
We present a revised alkali fusion method for the determination of trace elements in geological samples. Our procedure is based on simple acid digestion of powdered low‐dilution (flux : sample ≈ 2 : 1) glass beads where large sample dilution demanded by high total dissolved solids, a main drawback of conventional alkali fusion, could be circumvented. Three geological reference materials (G‐3 granite, GSP‐2 granodiorite and SGD‐1a gabbro) decomposed by this technique and routine tabletop acid digestion were analysed for thirty trace elements using a quadrupole ICP‐MS. Results by conventional acid digestion distinctly showed poor recoveries of Zr, Hf and rare earth elements due to incomplete dissolution of resistant minerals. On the other hand, results obtained by our method were in reasonable agreement with reference data for most analytes, indicating that refractory minerals were efficiently dissolved and volatile loss was insignificant.  相似文献   

6.
We present data for the concentrations of eleven rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Er, Yb, Lu) in eleven international geochemical reference materials obtained by isotope dilution multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS). We have analysed both rock powders and synthetic silicate glasses, and the latter provide precise data to support the use of these as reference materials for in situ trace element determination techniques. Our data also provide precise measurements of the abundance of mono-isotopic Pr in both glasses and powders, which allows more accurate constraints on the anomalous redox-related behaviour of Ce during geochemical processes. All materials were analysed in replicate providing data that typically reproduce to better than one percent. Sm/Nd ratios in all these materials also reproduce to better than 0.2% and are accurate to < 0.2% and can thus be used as calibrants for Sm-Nd geochronology. Our analyses agree well with existing data on these reference materials. In particular, for NIST SRM 610, USGS BHVO-2, AGV-1 and AGV-2, our measured REE abundances are typically within < 2% (and mostly 1%) of REE concentrations previously determined by isotope dilution analysis and thermal ionisation mass spectrometry, consistent with the higher degree of precision and accuracy obtained from isotope dilution techniques. Close agreement of results between basaltic glass reference materials USGS BHVO-2G and BCR-2G and the BHVO-2 and BCR-2 powders from which they were created suggests that little fractionation, concentration or dilution of REE contents occurred during glass manufacture.  相似文献   

7.
The USGS reference glasses GSA-1G, GSC-1G, GSD-1G, GSE-1G, BCR-2G, BHVO-2G and BIR-1G were investigated by different analytical techniques. All these materials have a geological (basaltic) matrix and are therefore useful in igneous geochemistry as matrix-matched reference materials for microanalytical techniques. The new GS glasses have trace elements in groups at concentration levels of about < 0.01, 5, 50 and 500 μg g-1. Their major element compositions have been determined by EPMA, and trace elements have been analysed by LA-ICP-MS and two isotope dilution techniques using TIMS and ICP-MS. EPMA and LA-ICP-MS analyses indicated that the USGS reference glasses are homogeneous at the μm to mm scale with respect to major (variations < 1-2%) and most trace elements (variations 1-4%). Trace element data obtained from the different analytical techniques agreed within an uncertainty of 1-5%, indicating that between method results are comparable. Therefore, the preliminary working values for the four USGS GS glasses calculated from these data have a low level of uncertainty.  相似文献   

8.
We report new data on the trace element concentrations of Mg, Cr, Mn, Co, Ni, Cu, Zn, Sr, Cd, Ba, La, Ce, Nd, Pb and U in USGS carbonate reference materials (MACS-1 and MACS-2) and compare solution ICP-MS and LA-ICP-MS trace element determinations on landfill calcites using calibration to different reference materials (MACS-1 and MACS-2 carbonate and NIST SRM 612 glass). Very good agreement (differences below 10% relative) was found between laser ablation and solution ICP-MS data for MACS-1 with higher concentrations of trace elements (values between 100 and 150 μg g−1), with the exception of Cu and Zn. Similarly good agreement was found for MACS-2 with lower trace element concentrations (units to tens of μg g−1), with the exception of Cr, Co and Zn. The MACS-1 reference material for calibration of LA-ICP-MS was found to be extremely useful for in situ determination of trace elements in real-world carbonate samples (landfill calcites), especially those present in calcite in higher concentrations (Mn, Sr, Ba; < 5% RSD). Less accurate determinations were generally obtained for trace elements present at low concentrations (∼ units of μg g−1). In addition, good agreement was observed between the instrument calibration to MACS and NIST SRM 612 glass for in situ measurements of trace elements in landfill calcites K-2, K-3 and K-4 (differences below 15% relative for most elements). Thus, the application of MACS carbonate reference materials is promising and points to the need for the development of new carbonate reference materials for laser ablation ICP-MS.  相似文献   

9.
Two reference samples, Albite AL-I and Iron Formation sample IF-G were analysed for their chemical composition by the International Working Group "Analytical Standards of Minerals, Ores and Rocks" (GIT-IWG). AL-I was processed in 189 kg and IF-G and 760 kg. 103 GIT-IWG laboratories participated in this collaborative study along with 171 geoanalysts. This study lasted 15 months (September 1982 - December 1983) and is the second undertaken by the GIT-IWG. Over 2400 units of data were collated. As a result of this international study, the major and minor elements have been well characterized in both the samples; however, more data on trace elements will be very welcome for a better definition of trace elements, although working values have been proposed for about forty trace elements in each sample. The first and the second collaborative studies undertaken by GIT-IWG demonstrate well the immense analytical potential of the GIT-IWG.  相似文献   

10.
The collection and preparation of four lake and four stream sediment reference materials are described. Provisional values related to both total concentrations and concentrations derived from partial extraction procedures are presented for major, minor and trace element constituents. As large amounts of samples (160–200 kg) have been prepared, they should be of interest to soil analysts.  相似文献   

11.
Three Cobalt-Rich Seamount Crust Reference Materials: GSMC-1 to 3   总被引：1，自引：0，他引：1  
A research project involving the preparation of three Co-rich crust reference materials (GSMC-1 to 3) has been preliminarily completed. The samples were collected from the eastern and central Pacific seamount zones and their main chemical composition is MnO2. After the raw materials were dried in ambient air and at low temperature (60-100 C), they were ground in a ball mill to form a well-mixed powder. The proportion of particle size fractions of < 74 μm and < 3 μm was over 98% and 50% respectively. The homogeneity of the materials was tested using wavelength dispersive X-ray fluorescence spectrometry (WD-XRF). The relative standard deviation (% RSD) of the measurements for all the selected elements in forty sub-samples randomly taken from the bottles was less than 0.4%. Sixteen laboratories from Germany, Russia, France, Australia and China participated in the collaborative analysis programme. Fifty seven elements or constituents were analysed, and among those, forty six elements were certified in each sample. The sum of contents of the major and minor elements or components was 99.5% for GSMC-1, 99.6% for GSMC-2 and 99.2% for GSMC-3.  相似文献   

12.
Three rock reference samples, Anorthosite AN-G, Basalt BE-N and Granite MA-N were analysed for their chemical composition by 122 laboratories belonging to the International Working Group "Analytical Standards of Minerals, Ores and Rocks" (IWG). 243 analysts took part in this first collaborative study which lasted only nine months, from June 1979 to March 1980. Despite this very short period, it has been possible to harvest over 6000 units of analytical data on major, minor and 53 trace elements. This excellent performance of the IWG members has rendered possible the chemical characterization of the three samples for not only the usual major and minor elements but also for 30 trace elements. This first study by the IWG Members demonstrates well their immense analytical potential and is exemplary in many respects.  相似文献   

13.
  相似文献   

14.
Data are reported for rare earth elements (REE), Y, Th, Zr, Hf, Nb and Ta in four geological reference materials using sodium peroxide (Na2O2) sintering and inductively coupled plasma-mass spectrometry. The described procedure was used by students during their thesis work. A compilation of their reference material data acquired over one year of laboratory work demonstrates the ease and reliability of the method and the high reproducibility of the analytical results. Relative standard deviations of up to thirty six measurements of one reference material were lower than 5% for Y and the REE. Reproduciblities of Zr, Hf, Nb, Ta and Th were higher at between 5% and 10%, and can be attributed to the inhomogeneous distribution of zircon and other trace mineral phases and uncorrected drift effects. The concentration data are compared to reference and literature values and demonstrate that the procedure is also accurate. New data on G-3 show some systematic deviations from G-2, which are statistically significant.  相似文献   

15.
Inductively coupled plasma mass spectrometry(ICP-MS) has become a powerful tool for providing reliable analytical results in many laboratories around the word. In this study, the mixture of HF and HNO3 acids in high-temperature and high-pressure closed-vessel digestion technique were used to decompose some Chinese reference materials, and thirty seven elements were determined by ICP-MS. Most of the results for Chinese soil reference materials were found to be in reasonable agreement with the reference values, except Cs, Ta, Li, Ge, Zn, Nd, Tb and Ta whose values need to be revised. Their precisions were typically lower than 5% RSD. However, the Precisions of Chinese clay reference materials, especially for GBW03102 and GBW03102a, were significantly different with reference values, probably reflecting the existence of a coarser-grained fraction(70 μm) in samples, and the formation of fluorides in Al-rich samples during sample decomposition by using the mixture of HF and HNO3 acids. Moreover, thirty-seven trace elements covering the mass range from Li to U in four Chinese clay reference materials were firstly provided with good precision and accuracy in this study.  相似文献   

16.
The collection and preparation of two soil reference samples and two till reference samples are described. Like their predecessors the LKSD series and the STSD series, the TILL series are characterized for total elements and for elements derived by partial extractions. Provisional data are presented for major, minor and trace elements. In addition, information data from a single source are provided for a number of elements derived by EPA digestions 3050 and 3051; these data allow a comparison with other partial extractions reported herein.  相似文献   

17.
Different batches of the new US Geological Survey (USGS) reference materials (RMs) BCR-2, BHVO-2, AGV-2, DTS-2 and GSP-2 and the original USGS RMs BCR-1, BHVO-1, AGV-1, DTS-1 and GSP-1 have been analysed by isotope dilution using thermal ionisation mass spectrometry (ID-TIMS) and by multi-ion counting spark source mass spectrometry (MIC-SSMS). The concentrations of K, Rb, Sr, Ba and the rare earth elements were determined with overall analytical uncertainties of better than 1% (ID-TIMS) and 3% (MIC-SSMS). The analyses of different aliquots and batches of BCR-2, BHVO-2, AGV-2 and GSP-2, respectively, agree within 1%, i.e. approximately the analytical uncertainties of the data. This indicates an homogeneous distribution of the trace elements in these RMs. Differences in element concentrations of up to 17% in different aliquots of the depleted RM DTS-2 are outside the analytical uncertainty of our data. They may be attributed to a slightly heterogeneous distribution of trace elements in this dunite sample. Our trace element data for BCR-2, BHVO-2, AGV-2 and GSP-2 agree within about 3% with preliminary reference values published by the USGS. They also agree within 1-6% with those of the original RMs BCR-1, BHVO-1, AGV-1 and GSP-1. Large compositional differences are found between DTS-2 and DTS-1, where the concentrations of K, Rb, Sr and the light REE differ by factors of 2 to 24.  相似文献   

18.
Four silicate glasses were prepared by the fusion of about 1 kg powder each of a basalt, syenite, soil and andesite to provide reference materials of natural composition for microanalytical work. These glasses are referred to as ‘Chinese Geological Standard Glasses’ (CGSG) ‐1, ‐2, ‐4 and ‐5. Micro and bulk analyses indicated that the glasses are well homogenised with respect to major and trace elements. Some siderophile/chalcophile elements (e.g., Sn, Pt, Pb) may be heterogeneously distributed in CGSG‐5. This paper provides the first analytical data for the CGSG reference glasses using a variety of analytical techniques (wet chemistry, XRF, EPMA, ICP‐AES, ICP‐MS, LA‐ICP‐MS) performed in nine laboratories. Most data agree within uncertainty limits of the analytical techniques used. Discrepancies in the data for some siderophile/chalcophile elements exist, mainly because of possible heterogeneities of these elements in the glasses and/or analytical problems. From the analytical data, preliminary reference and information values for fifty‐five elements were calculated. The analytical uncertainties [2 relative standard error (RSE)] were estimated to be between about 1% and 20%.  相似文献   

19.
A dunite reference material has been prepared as part of the reference materials programme at the National Geophysical Research Institute, Hyderabad, India. The scarcity of reference materials for undertaking the chemical analysis of ultramafic rocks for major and trace elements justified the preparation of such a rock reference material. A 300 kg sample of starting material was collected from an active quarry near the town of Salem in Tamil Nadu, southern India. The sample was homogenized and an invitation for round robin participation was published in Geostandards Newsletter (October 1995). A total of twenty seven international laboratories participated in the study, providing information on the total element concentration of major, minor, trace and rare earth elements. Following data compilation, outlier rejection, and statistical analysis, proposed and indicative total element concentrations are reported for twenty four elements.  相似文献   

20.
  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号