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1.
The contents of total carbon, hydrogen, nitrogen and sulfur in twenty-seven geological reference materials, issued by five producer organisations (USGS, CCRMP, ANRT, NIST and GSJ) were determined using an automated simultaneous elemental analyser following combustion. In order to complete gasification of C and N in some geological materials, the combustion temperature needed to be greater than 1150 °C. The calibrator prepared from known amounts of reagent material was not adopted for more than 1.2% m/m of H. Unrealistically high values in certain materials supposed to contain less than 1000 μg g−1 S may be due mainly to memory effects. The limit of detection was 50 μg g−1 for C and N, 500 μg g−1 for H and 1000 μg g−1 for S. Although the blank value of C and N was always stable and less than one third of the detection limit, it had a slightly higher value for N and S. By repeating long-term analysis, high reproducibility for each of the four elements was verified. The method has been applied satisfactorily to a variety of geological reference materials, and recommended values for C, H and N for most of the reference materials studied have been tabulated.  相似文献   

2.
We present a revised method for the determination of concentrations of rare earth (REE) and other trace elements (Y, Sc, Zr, Ba, Hf, Th) in geological samples. Our analytical procedure involves sample digestion using alkaline fusion (NaOH-Na2O2) after addition of a Tm spike, co-precipitation on iron hydroxides, and measurement by sector field-inductively coupled plasma-mass spectrometry (SF-ICP-MS). The procedure was tested successfully for various rock types (i.e., basalt, ultramafic rock, sediment, soil, granite), including rocks with low trace element abundances (sub ng g−1). Results obtained for a series of nine geological reference materials (BIR-1, BCR-2, UB-N, JP-1, AC-E, MA-N, MAG-1, GSMS-2, GSS-4) are in reasonable agreement with published working values.  相似文献   

3.
Complete dissolution is essential to obtain accurate analytical results using ICP-MS. In this study, decomposition techniques (i.e. acid digestions using Savillex Teflon vials, a high pressure digestion system and microwave oven, a combined lithium tetraborate fusion - HF/HNO3 acid decomposition and sodium peroxide sinter) for the total dissolution of different types of geological reference materials have been investigated. Savillex Teflon vial HF/HNO3 digestion is effective for basaltic samples. The high pressure HF/HClO4 digestion (PicoTrace TC-805 digestion system, Bovenden, Germany) allows dissolution of basalts and ironstones. Granites and magnetite-rich samples can be dissolved using a high pressure HF/H2SO4 method. Geological samples cannot be effectively attacked by microwave acid digestion. A combined lithium tetraborate fusion - HF/HNO3 acid digestion method allows complete dissolution of many different types of geological materials; however, this method precludes the determination of volatile elements due to the high fusion temperature (1000 °C). A sodium peroxide sinter method at 480 °C has the potential for the rapid determination of Y, Sc and REE in different types of geological materials. However, the lack of ultra-pure reagents precludes the use of lithium tetraborate fusion and sodium peroxide sinter methods for the measurement of geological samples with low trace element abundances.  相似文献   

4.
Experimental results for most rare-earth elements, yttrium and thorium in several international geological reference samples are presented and compared with other published values, where available. The analytical method used to obtain these results involved a preliminary concentration of the rare-earths On milligram quantities of iron as carrier for atomic-absorption, flame-emission and spectrophotometric determinations, or on milligram quantities of Fe2O3, Al2O3 and SiO2 as carriers for optical-emission spectrometric determination.  相似文献   

5.
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   

6.
Provisional values related to element concentration derived from partial extractions as well as some additional total concentration data are reported for eight CCRMP sediment reference materials. These values are intended to supplement previously published data for these samples. The partial extractions for which data are reported include dilute HNO3 - dilute HCl, concentrated HNO3 -concentrated HCl and concentrated HNO3 -concentrated HClO4.  相似文献   

7.
A new method has been developed for the determination of platinum and palladium based on separation and preconcentration with a microcolumn packed with nanometric TiO2 immobilised on silica gel (immobilised nanometric TiO2) prior to their determination by inductively coupled plasma-atomic emission spectrometry. The optimum experimental parameters for the preconcentration of Pt and Pd, such as the pH of the sample solution, its flow rate and volume, the type and concentration of eluent and interfering ions, have been investigated. Platinum and Pd could be quantitatively retained by immobilised nanometric TiO2 in the pH range 6–8, then eluted completely with 2.0 ml of 3% m/v thiourea in 1.0 mol l−1 HNO3. The detection limits of this method for Pt and Pd were 12 and 7. 6 ng l−1 with an enrichment factor of 100, and the relative standard deviations were 4.7% and 3.3% at the 10 ng ml−1 level. The method has been applied for the determination of Pt and Pd in geological samples with satisfactory results.  相似文献   

8.
New data are presented for the analysis of the elements: REE, Na20, Fe2O3, Cr, Co, Rb, Cs, Ba, Hf, Ta, Th and Il in twenty-five less well known carbonate and industrial geological reference materials by instrumental neutron activation analysis. The materials include NBS 1c, 15e, 88a and 120b from the National Bureau of Standards, Washington DC; GFS 400-403, 405, 407, 411, 412, 415 and 417 carbonate materials from George Fredrick Smith, Columbus, Ohio and BCS 267, 269, 309, 315, 319, 367, 368, 375, 376, 381 and 382/1 from the Bureau of Analysed Samples, Middles-borough, Cleveland, UK. Particular attention has been given to the correction of interferences due to the fission of uranium in the determination of the elements La, Ce, Nd and Zr.  相似文献   

9.
A simple and reliable method to separate rare earth elements (REE) from Mg, Fe, K, Na, Ca and Ba in ultramafic rocks has been developed, thereby concentrating their abundances. The sample (0.3 g) was digested with HF and HNO3 in a PTFE bomb, placed in a stainless steel container and, after drying, the insoluble residue was dissolved in 6 ml of 10% v/v HNO3. Following the addition of 50% triethanolamine and 30% m/v NaOH solution, the REE were precipitated along with Mg(OH)2, such that the majority of Fe, K and Na in the solution could be separated by centrifuging. The precipitate was dissolved in 1 ml HNO3 and a buffer solution of NH4Cl/NH4OH at pH = 9.0 was added to precipitate the REE along with any remaining Fe as Fe(OH)3, and so achieve separation from Mg, Ca and Ba, which remained in the solution. In this way, REE could be separated from major elements and were concentrated by a factor of about 60. The recovery of REE was more than 95% using this method. Four ultramafic rock reference materials, PCC-1 (USGS), JP-1 (GSJ), DZE-1, DZE-2 (IGGE) and one new proficiency testing sample GeoPT12 (GAS Serpentinite) were analysed by ICP-MS using indium as an internal standard. The quantitation limits were about 0.02–0.2 ng g−1. Smooth chondrite-normalised REE patterns were obtained with a precision for REE determination of about 2–9%.  相似文献   

10.
Abundances of twenty four trace elements, including Y and fourteen rare earth elements (REE), are reported for eighty six geological reference materials and four proficiency testing samples. Analytical data were obtained by ICP-MS using solution nebulisation after mixed acid digestion (HF-HClO4) under pressure. Analysed samples cover a wide range of element concentrations and mineralogical compositions, including samples for which there are few previously published data. Precision for elemental determinations in nearly 90% of the samples analysed is better than 5%. Accuracy, estimated by comparison with data from compilations is better than 6% for well characterized reference materials. Results obtained for samples that are low in trace elements are often significantly lower than compiled reference values. A critical discussion of the compiled data sets, especially for Y and the REEs, indicates that some reference values seem to be erroneous.  相似文献   

11.
In this contribution we evaluate the capabilities of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) using a 12 μm spot size. Precision, accuracy and detection limits were assessed on the USGS BCR-2G reference material. We demonstrate that the 12 μm LA-ICP-MS analyses of experimentally-grown amphibole and garnet are in excellent agreement with secondary ion mass spectrometry (SIMS) trace element determinations on the same crystals. The 12 μm spot size configuration was subsequently used to determine trace element crystal-melt partition coefficients (Dc/m) for a wide range of trace elements in amphibole in equilibrium with a basanitic melt. The following strategy to determine accurately and evaluate Dc/m is proposed. One or more major elements determined previously by electron probe microanalysis (EPMA) was used to ensure consistency between EPMA and the composition of the aerosol produced by the laser ablation. Measured Dc/m values were successively evaluated using the lattice strain model. The use of this strategy significantly improved the precision and accuracy of Dc/m determination when a LA-ICP-MS configuration with a high spatial resolution was employed.  相似文献   

12.
Data are reported for rare earth elements (REE) in three geological glass reference materials (BIR-1G, BHVO-2G and BCR-2G) using a UV (266 nm) laser ablation ICP-MS system and the classical (HF-HClO4) acid decomposition method, followed by conventional nebulisation ICP-MS. External calibration of laser ablation analyses was performed using NIST SRM reference materials with internal standardisation using 29Si and 44Ca. Replicate analyses of reference basaltic glasses yielded an analytical precision of 1-5% (RSD) for all the elements by solution ICP-MS and 1-8% (RSD) by laser ablation ICP-MS. The relative differences between the REE concentrations measured by solution and laser ablation ICP-MS compared with the reference values were generally less than 11 % for most elements. The largest deviations occurred for La determined by solution ICP-MS in BIR-1G. The results of both solution and laser ablation ICP-MS agreed well, generally better than 7%, with the exception of La, Pr and Sm in BIR-1G. The measured REE laser ablation data for BIR-1G, BHVO-2G and BCR-2G agreed with the previously published data on these basaltic reference glasses, within a range of 0-10% for most elements. No significant influences were observed for the predicted spectral interferences on some REE isotopes in the analysis of basaltic glasses.  相似文献   

13.
The paper presents preliminary results of the use of a high resolution double-focussing, magnetic sector inductively coupled plasma-mass spectrometer (HR-ICP-MS) with ultraviolet laser ablation (LA) for the bulk analysis of geological materials fused with Li2B4O7. Detection limits are based on data from precision measurements of a fused SiO2 sample of high purity, and sensitivity data (cps/μg g-1) obtained on the Reference Material (RM) Syenite SY-2. For many trace elements, the detection limits are better than 0.05 μg g-1 using a sample to flux weight ratio of 1:7.
Calibration curves, which are based entirely on RMs, are established for Hf, Ta, Tb, Tm and Lu. They indicate that, even at this early stage in the development of the technique, data accurate to ˜ 25% can be collected. It is concluded that the method may prove to be a valuable supplement to XRF for low level element concentration measurements; it is also very practical, as the same sample discs can be used for both XRF and LA-ICP-MS analyses.  相似文献   

14.
Trace elements in the Geological Survey of Japan carbonate reference materials Coral JCp-1 and Giant Clam JCt-1 were determined by inductively coupled plasma-mass spectrometry after digestion with 2% v/v HNO3. A standard addition method was adopted in this determination in order to neutralise the Ca matrix effect. In addition, Sc, Y, In and Bi were used as internal standards to control the matrix effect and correct instrumental drift. Of the eighteen elements measured in JCp-1, precisions for fourteen elements, including Cu, Cd and Ba, were better than 10% RSD and concentrations ranged from 0.002 μg g-1 (Cs) to 8.02 μg g-1 (Ba). The concentrations of measured trace elements in JCt-1, except for Cu, were lower than those in JCp-1. Precisions for all elements with concentrations higher than 0.04 μg g-1 in JCt-1 were also better than 10% RSD and concentrations were found to be between 0.001 μg g-1 (Cs) and 4.84 μg g-1 (Ba). The concentrations of more than fifteen trace elements in the aragonite reference materials are reported here for the first time. Both reference materials are suitable for use in geochemical studies of environmental reconstruction based upon biogenic carbonate materials.  相似文献   

15.
In this paper, a method developed to determine the major, minor and trace elements, including carbon and the four halogens, in seamount phosphorite involving a modern XRF spectrometry technique is described. Ultra-fine (99% v/v < 40 μm) powder samples (4 g) were directly pressed into pellets (Φ= 30 mm). For elements having an analytical line lower in energy than the energy of Fe Kα line absorption edge, the inter-element absorption-enhancement effects were corrected using an influence coefficient method. For the other elements, the matrix effects were corrected using the ratio of element peak to Rh Kα Compton peak (for I, Rh K|3 Compton peak was used instead). The relative standard deviation was smaller than 1.0% for the major elements (except C, Na and Cl). The detection limit levels of C, F, Cl, Br and I were 30, 20, 0.8, 0.2 and 0.3 (μg g−1 respectively for 100 s count time of background. The accuracy of this method was tested by evaluating determinations on three certified reference materials. The direct analysis of major and minor elements in geological materials by pressed pellet without any chemical procedures makes XRF spectrometry a particularly environment-friendly analytical technique.  相似文献   

16.
To understand and/or avoid small-scale chemical heterogeneities within geological materials prepared as normal thin sections, in situ multiple trace element determination coupled with the simultaneous microscopic observation of the sample during analysis is preferable. We have examined fifty trace elements in thin (< 30 μm) layers of the NIST SRM 614 and 616 glass reference materials by LA-ICP-MS using different pit diameters and internal standard elements (Ca and Si). Compositional heterogeneities of Tl, Bi, As and Cd were found in NIST SRM 614 and 616 at the spatial resolution of ca. 10 0 μm. Except for these elements, the RSDs of six determinations for most elements were better than 10% in NIST SRM 614 when ablation diameters were < 50 μm. The measured concentrations for most elements in NIST SRM 614 and 616 agree with previous values in the literature at the 95% confidence level with the exception of W and Bi. New LA-ICP-MS data for K, As and Cd are also reported. The results support the view that the latest LA-ICP-MS is a powerful and flexible analytical technique for the determination of multiple ultra-trace element compositions in geological materials prepared as normal thin sections of the type that has been used for polarising optical microscopic observations since the end of the 19th century.  相似文献   

17.
A simple and selective method of flow injection (FI) using a micro-column packed with chelating resin YPA4 as solid phase extractant was developed for the preconcentration and separation of trace amount of noble metals, Au(III), Ag(I), Pd(II) and Pt(IV), followed by ICP-AES determination. In HNO3 media, the chelating resin was selective towards Au(III), Ag(I), Pd(II) and Pt(IV), and the analysed ions were readily desorbed quantitatively with 5 ml of 2.5% m/v thiourea. Effects of acidity, sample flow rate and concentration, elution solution and interfering ions on the recovery of the analytes were systematically investigated. Under optimum conditions, the adsorption capacities of YPA4 for Au(III), Ag(I), Pd(II) and Pt(IV) were 67.2, 43.1, 64.8 and 27.6 mg per gram of resin in HNO3 media, respectively. It was found that YPA4 could be used for more than eight runs in HNO3 media without loss of capacity. The proposed method was used for the determination of trace noble metals in geological and environmental samples, and the analytical results obtained were in good agreement with the recommended values.  相似文献   

18.
This paper describes a technique for the preparation of a titanite (CaTiSiO5) glass calibration material for use in in situ microanalysis of major, minor, and trace elements in geological materials. The starting composition was a titanite matrix doped with minor and trace elements at ∼ 200 μg g-1. The elements Sc, Y, REEs, Th and U were added in the form of nitrates in solution, and the elements V, Cr, Mn, Fe, Co, Ni, Zr, Nb, Hf and W were added as solid oxides. The synthetic titanite glass was produced by direct fusion by resistance heating in graphite electrodes at 1600-1700 °C, and quenched in air. Backscattered electron images indicate good homogeneity, with no signs of separate phases or vesicles, and analysis of the major elements Ca, Ti and Si by electron microprobe showed relative standard deviations between 0.5 and 0.7%, based on six independent measurements. Deviations from nominal concentrations for Ca, Si and Ti were measured to -1.2, -3.3 and -0.8%, respectively. The homogeneity of the trace elements in the glass was assessed by LA-ICP-MS analyses, using NIST SRM 610, 612 and 616 as external calibrators, and Ca as the internal standard element. Determinations were made both with a quadrupole mass spectrometer and a sector field instrument, and both raster and spot modes of analysis were used. For the majority of doped elements, precision was better than 10%, and relative deviations from nominal values were, with few exceptions, between 5 and 10%.  相似文献   

19.
A method is described for the determination of mercury at nanogram levels in geological materials by flameless atomic absorption spectroscopy after metal vapor generation. Mercury is converted to a soluble form by H2SO4-HNO3 attack in a teflon bomb at 180°C for 90 minutes. Metal Hg vapor is obtained by reaction with combined NaBH4-NaOH using the Perkin-Elmer MHS - 10 hydride system and determined at room temperature. Mercury can be easily determined in most silicate materials. The sensitivity of the method depends essentially on the purity of the reagents and contaminations during handling rather than on instrumental capabilities. A detection limit of about 10 ng/g Hg for 0.5 g samples has been achieved with the use of normal "suprapure" reagents. Mercury contents on some USGS, CRPG and ANRT reference samples are reported.  相似文献   

20.
Total sulfur is an analyte for which there are few determinations published, despite the fact that it is a very important element (e.g., a major element in most ores, an important gas constituent in global warming, an active participant in acid drainage). Most geological reference materials have very poor quality sulfur results, that is with relative standard deviations (RSD) in the range of 30–50%, even for concentrations over 100 μg g−1 S, which compromises their use as calibrators. In order to provide modern results with low RSD, sulfur was determined in twenty-nine geological reference materials with a state-of-the-art elemental S/C analyser using metal chips (certified reference materials with a traceability link) and analytical grade sulfur for high concentration samples. Analytical parameters (sample mass, crucible degassing, calibration strategy, etc.) were optimised by testing. Our results agreed with reference material values provided by issuing bodies. Results for CCRMP SY-2 (129 ± 13 μg g−1 S), which has been proposed as a sulfur reference material, were in agreement with the proposed modern value of 122 ± 3.7 μg g−1 S.  相似文献   

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