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1.
Fluorine, chlorine, bromine, iodine and sulfur were determined in seventeen geological reference materials after extraction by pyrohydrolysis. Fluorine, Cl and S (as sulfate ions) were determined in the extraction solution by ion chromatography with detection limits of around 0.2 mg l−1. Bromine and I were measured by ICP-MS with detection limits of 1 μg l−1 for Br and 0.1 μg l−1 for I. For rock samples, using normal extraction conditions (500 mg of sample and 100 ml of final solution) detection limits were 40 mg kg−1 for F and Cl, 15 mg kg−1 for S, 0.2 mg kg−1 for Br and 0.02 mg kg−1 for I. These detection limits may be improved by increasing the amount of sample and hence the concentration of the final solution. Water was also determined using an extraction technique based on H2O degassing, reduction on zinc at 1000 °C and H2 manometry. Our results for fluorine, chlorine, sulfur and water are in good agreement with literature data. Very few reference materials have recommended values for bromine and especially for iodine. Among the analysed samples, three are new reference materials: BHVO-2, BCR-2 and AGV-2.  相似文献   

2.
The present study describes a method for the extraction of Pt, Pd, Rh, Ru, Ir and Au from various geological materials after fusion with sodium peroxide in zirconium crucibles involving samples that vary in mass from 1 g to more than 20 g. Precipitation is brought about by reduction of the platinum-group elements (PGEs) with Sn2+, using selenium and tellurium as carriers in the presence of a catalyst (KI). The extraction yields obtained by this method are between 95 and 100% for PGEs. Gold is less well extracted (around 80%). Detection of the noble metals in the extraction residues is carried out by using ICP-MS. The results obtained by this technique are reported for five CCRMP certified reference materials and are close to their certified values. The elements were also determined in a natural glass sample melted during a meteoritic impact and contaminated by PGEs at ultra-trace concentrations.  相似文献   

3.
A procedure for the digestion and analysis of quartz samples was developed to measure trace element concentrations in natural quartz. The certified glass sand reference material UNS-SpS was chosen to assess the precision, accuracy and detection limit of the analytical method. Quartz was digested with HF/HNO3 in a closed glassy carbon vessel and analysed by means of quadrupole ICP-MS with external calibration. Analyte concentrations of the sand UNS-SpS were compared with certified and other values from the literature. The abundances of a number of elements (Pr, Gd, Ho and Er) in the reference material are reported here for the first time. The procedure was then applied to three quartz samples from different geological settings to show that trace element data by ICP-MS can distinguish the origin of the sample.  相似文献   

4.
A comparison between HBr-HCl and HBr-HNO3 based anion chemistry is presented to test the efficiency of Pb purification in the preparation of samples for isotope ratio measurement by ICP-MS. It was found that the small advantages in yield and blank offered by the HNO3-based method were more than compensated by the more effective matrix removal of the HCl-based method. Apart from very zinc rich matrices (e.g., sphalerite), a careful single pass purification using HBr and HCl removed more than 99.9% of the matrix. In preparation for the isotope ratio analysis, a small (2–5% m/v) liquid sample aliquot was analysed to determine U, Th and Pb concentrations by solution quadrupole ICP-MS. This allowed accurate prediction of the expected ion signal and permitted optimal spiking with Tl, if desired, for mass bias correction. Long-term results for international rock reference materials showed reproducibilities of better than 1% (Th/U) and 1.5% (U/Pb). For most geological applications, such analyses obviate the need for isotope dilution concentration measurements.  相似文献   

5.
A precise and simple method for the determination of lithium concentrations in small amounts of silicate sample was developed by applying isotope dilution-inductively coupled plasma-mass spectrometry (ID-ICP-MS). Samples plus a Li spike were digested with HF-HClO4, dried and diluted with HNO3, and measured by ICP-MS. No matrix effects were observed for 7Li/6Li in rock solutions with a dilution factor (DF) of 97 at an ICP power of 1.7 kW. By this method, the determination of 0.5 μg g-1 Li in a silicate sample of 1 mg can be made with a blank correction of < 1%. Lithium contents of ultrabasic to acidic silicate reference materials (JP-1, JB-2, JB-3, JA-1, JA-2, JA-3, JR-1 and JR-2 from the Geological Survey of Japan, and PCC-1 from the US Geological Survey) and chondrites (three different Allende and one Murchison sample) of 8 to 81 mg were determined. The relative standard deviation (RSD) was typically < 1.7%. Lithium contents of these samples were further determined by isotope dilution-thermal ionisation mass spectrometry (ID-TIMS). The relative differences between ID-ICP-MS and ID-TIMS were typically < 2%, indicating the high accuracy of ID-ICP-MS developed in this study.  相似文献   

6.
电感耦合等离子体质谱法测定磷矿石中的碘   总被引：3，自引：1，他引：2  
建立了电感耦合等离子体质谱法测定磷矿石中碘的方法。试样经磷酸、高氯酸分解,用氨水调至弱碱性,直接用电感耦合等离子体质谱法测定,方法检出限为0.33μg/g,加标回收率为95.0%~97.4%,精密度(RSD,n=12)为2.77%~3.17%。经磷矿石国家一级标准物质(GBW 07210和GBW 07211)验证,结果满意。  相似文献   

7.
In this study, the Cd isotopic composition of various geological reference materials and anthropogenic samples was investigated. The measurements were made by multicollector ICP-MS and instrumental mass fractionation was controlled using a "sample-standard bracketing" technique. Cadmium isotopic data are reported relative to an internal Cd solution (Cd Spex) and expressed as the 114 Cd/110Cd delta value. Two other Cd solutions (Prolabo and JMC) were analysed and yielded the same 0% delta value. A fractionated Cd metal sample (Münster Cd) was used as a secondary reference material for Cd isotopic measurements and we obtained a 114 Cd/110 Cd delta value of 4.48% relative to Cd Spex solution. As opposed to multi-stage Cd purification previously published in the literature, a new one step anionic exchange purification using dilute HCl for the analysis of Cd isotopes in geological samples was developed. This method enabled a high recovery (> 95%) and effective separation of the sample matrix to be achieved. The long-term external reproducibility was evaluated at 0.12% (2 standard deviations) for the 114 Cd/110Cd ratio, based on reference solutions and replicated measurements of samples over one year. The variation of Cd isotopic composition of natural terrestrial samples is restricted to a small range of 0.4%, which is similar to previously reported results. In contrast, large variations of Cd isotopic composition were found for anthropogenic samples with values as low as −0.64% for a dust sample issued from a lead smelter and values as high as +0.50% for NIST SRM 2711 (metal-rich soil). These variations are 10 times larger than the reproducibility and suggest that Cd isotopes can be useful as tracers of anthropogenic sources of Cd in the environment.  相似文献   

8.
The platinum-group elements (PGE) and gold have been determined in twenty international rock reference materials by inductively coupled plasma-mass spectrometry (ICP-MS) after pre-concentration by a nickel sulfide fire assay. It was possible to achieve determination limits for a 50 g sample that ranged from 1 pg g-1 (Rh) to 23 pg g-1 (Au). Compared to published certified and recommended values for rock reference materials, the trueness of the method was found to be good. However, in some cases we observed large deviations for all elements in the sub 10 ng g-1 range within individual reference sample splits. Our results show that the PGE and Au are inhomogeneously distributed in the reference materials analysed here, where they are present in low concentrations, using 50 g test portions.  相似文献   

9.
A direct method for the determination of lead isotopic ratios by laser ablation-inductively coupled plasma-quadrupole mass spectrometry (LA-ICP-QMS) is presented. Samples of lake sediments were ground and pressed as pellets before being analysed. Mass bias was corrected by analysing an external calibration sample manufactured with pure silica doped with NIST SRM 981 solution. The efficiency of the mass bias correction was checked by comparing the ICP-MS data with lead isotopic ratios determined by thermal ionisation mass spectrometry (TIMS). The average long term reproducibilities were 0.40%, 0.40%, 0.20% and 0.30% (RSD) respectively for the 206Pb/204Pb, 207Pb/204Pb, 206Pb/207Pb and 208Pb/206Pb ratios. The method was applied to the study of lake sediment samples, in order to determine the amount and origin of historical contamination by lead.  相似文献   

10.
Three new certified reference materials (CRM), certified for the platinum-group elements (PGE), GPt-8, GPt-9 and GPt-10 were developed based on the previous CRMs IGGE GPt-1 to GPt-7. The PGE concentration of GPt-8 is about 1 ng g-1. GPt-9 and GPt-10 are ore samples with PGE concentrations of more than 1 μg g-1. A multi-laboratory collaborative analysis scheme was adopted in the certification procedure, in which nine highly-experienced institutes and laboratories participated. The samples were analysed for the six platinum-group elements by nickel sulfide mini fire assay, with Te coprecipitation, and were determined by ICP-MS. Osmium was determined by isotope dilution.  相似文献   

11.
A method developed for radiochemical determination of gold in rock samples has been applied to six Bulgarian, four ZGI (GDR) and one USGS geostandards. The method is based on acid dissolution of the sample, followed by extraction of gold with copper diethyldithiocarbamate solution in CHCl3. The chemical yield was determined by using 199Au tracer. The present data are compared with published values for the ZGI and USGS samples.  相似文献   

12.
Nanometre-sized alumina was chemically modified with gallic acid (GA) and used as a solid phase adsorption material for the determination of trace amounts of V, Nb and Ta in natural water, soil and stream sediment samples by inductively coupled plasma-mass spectrometry. The effects of pH, sample flow rate and volume, elution solution and interfering ions on the recovery of the analytes were investigated. The results showed that V, Nb and Ta could be adsorbed at pH 4.0 and recovered with 1 ml of 2.0 mol l-1 HCl. Under optimised conditions, the adsorption capacity of GA-modified nanometre-sized Al2O3 was found to be 7.0, 8.9, 13.3 mg g-1 for V, Nb and Ta, respectively. The limits of detection were as low as 0.25, 0.24 and 0.66 ng l-1 for V, Nb and Ta, respectively with a concentration factor of fifty. The recovery of V, Nb and Ta for spiked water samples was between 85.7 and 116%. The developed method has also been applied to the determination of trace V, Nb and Ta in soil and stream sediment certified materials, and the determined values were in a good agreement with the certified values.  相似文献   

13.
One or two gram aliquots of twelve reference materials with low platinum-group element (PGE) abundances (Ir concentrations ranging from 30 to 510 pg g-1) were analysed by isotope dilution ICP-MS using an on-line chromatographic matrix separation after acid digestion in a high pressure asher (HPA-S) to determine the concentrations of Ru, Pd, Re, Ir and Pt. Osmium concentrations were determined via ID-ICP-MS but as volatile OsO4, whereas Rh concentrations were calculated by comparing the peak areas of the chromatographic peak with that of a standard solution. Validation of the method was performed and the concepts of traceability and measurement uncertainty were applied to assure comparability. The reference materials BCR-2, BHVO-1, BHVO-2, BIR-1, DNC-1, EN026 10D-3, MAG-1, RGM-1, SCo-1, SDO-1, TDB-1 and W-2 were investigated to test for their usefulness for certification. The use of TDB-1 is highly recommended because it is homogeneous at the two gram level and many values based on several different analytical procedures have been published. It is recommended that our efforts should focus on the certification of this reference material to reduce the uncertainties of its currently certified values (Pd and Pt only) and to assign certified values to the other PGE and Re. It is necessary to have at least one well-characterised RM for validation of methods applied to the analysis of PGE and Re in low abundance samples, although the matrix of TDB-1 might not completely match those of many samples.  相似文献   

14.
Inductively coupled plasma-mass spectrometry (ICP-MS) after NiS fire assay-Te co-precipitation was employed in the determination of Ru, Rh, Pd, Os, Ir and Pt at ng g-1 levels in six platinum-group element (PGE) geological reference materials. In general, the average of several results was in good agreement with the certified values taking into account respective uncertainties. High relative standard deviations were observed for the reference materials GPt-3 and GPt-4. Problems associated with the NiS fire assay procedure and PGE determination at the sub-10 ng g-1 level are reviewed and discussed.  相似文献   

15.
The carbonate-carbon (CO2) content of forty-one geochemical reference samples has been determined by coulometric method following acid treatment of the sample for releasing CO2. The method is superior to the conventional methods in speed, accuracy, sensitivity, specificity, and the coverage of CO2 range. The results on NBS limestone samples agree well with the certified values. The precision of the method is 0.5 % r.s.d., and the practical detection limit is 10 ppm C.  相似文献   

16.
We present new concentration data for twenty four lithophile trace elements in NIST certified reference material glasses SRM 610-SRM 611 in support of their use in microanalytical techniques. The data were obtained by solution ICP-MS and isotope dilution TIMS analysis of two different sample wafers. An overall assessment of these new results, also taking into account ion probe studies that have been published in the literature, shows that these wafers can be considered to be homogeneous. Therefore, individually analysed wafers are believed to be representative of the entire batch of the SRM 610-611 glasses. Possible exceptions are the alkali metals (and a few volatile or non-lithophile trace elements). The analysed concentrations range between 370 μg g−1 (Cs) and 500 μg g−1 (Sr) and agree well with published values. On the basis of our new data and data recently published in the literature we propose "preferred average" values for the elements studied. These values are, within a few percent, identical to those proposed by other workers.  相似文献   

17.
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   

18.
Thirty-seven trace elements, including rare-earth elements, have been determined by ICP-MS in twenty-eight international rock standards using routine sample preparation techniques. Samples were decomposed by either pressurized HF-HCIO4-aqua regia attack, or by lithium borate fusion. Generally, the ICP-MS data for geological rock standards presented here agree well with certified values. However, the results for light rare earth elements appear to be systematically low in comparison with the published working values.  相似文献   

19.
采用HNO3-H2O2体系对植物样品进行风冷回流消解,电感耦合等离子体质谱法(ICP-MS)同时测定植物样品中46个元素的含量。将称有样品的磨口锥形瓶加装风冷管后直接放在普通平板铝块电热板上,一次可对45个锥形瓶回流装置同时进行加热,不需要严格地规定消解时间,保证回流加热微沸消解至消解完全即可。植物标准物质(GBW 10012、GBW 10014和GBW 10019)的分析结果与标准值相一致,方法精密度(RSD,n=6)为0.44%～5.59%。与干法灰化消解和微波消解等样品处理方法相比较,操作简单快捷,试剂用量少,空白值较低,溶液盐度较小,有利于植物样品中多元素ICP-MS同时测定。采用调试液调节ICP-MS仪器测定的最佳化,确定了ICP-MS测定的最佳条件,同时探讨了元素之间的干扰关系,采用数学校正法有效地消除了测定的干扰。  相似文献   

20.
Application of Laser Ablation ICP-MS to U-Th-Pb Dating of Monazite   总被引：2，自引：1，他引：2  
Recent advances in laser ablation ICP-MS techniques allow accurate U-Th-Pb age dating of monazites that are as young as several tens of million years to a precision better than 2%. Accuracy of the age determinations has been improved by true real-time mass bias correction via nebulisation of a solution containing enriched 233U and natural Tl isotopes. The Tl-U tracer solution eliminates possible effects of variable sample matrices on the precision and accuracy of measured isotopic ratios. Mass bias corrections based on measured 205Tl/233U ratios in the tracer solution allow direct measurement of 235U in monazite. Combined with high-sensitivity laser ablation ICP-MS measurements, direct measurement of 235U particularly improves the precision of U-Pb dating of young monazites. Correction for laser-induced Pb/U and Pb/Th elemental fractionation is based on a mathematical treatment of time resolved count-rate data that is independent of laser ablation characteristics, does not require external standardisation and allows variable laser pit size or raster patterns for each measurement. The new procedures make the LA ICP-MS technique more flexible for in situ U-Th-Pb analysis.  相似文献   

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