锗矿石和铟矿石化学成分分析标准物质研制

目前国内外没有以稀散元素锗、铟为特征元素的矿石标准物质,为了满足我国地质找矿的需求,本文采集广东省韶关凡口铅锌矿作为锗矿石候选物,广西南丹铜坑铅锌矿作为铟矿石候选物,依据国家一级标准物质技术规范,由10家实验室采用化学分析方法和现代仪器分析方法协作定值,研制了1种锗矿石标准物质(GBW07831)和1种铟矿石标准物质(GBW07833)。锗矿石标准物质定值组分为45项,铟矿石标准物质定值组分为47项,包括特征元素、共存元素、稀土元素(15项)、造岩元素和痕量元素,其中锗矿石中锗含量为21.6×10-6,铟矿石中铟含量为39.7×10-6。研制的2种标准物质丰富了我国矿石标准物质的种类,可用于锗、铟矿石化学成分分析测试的量值标准和日常质量监控。     

Analysis of Sediments and Soils by X-Ray Fluorescence Spectrometry Using Matrix Corrections Based on Fundamental Parameters

Wavelength dispersive X-ray fluorescence spectrometry (WD-XRF) is widely used for the analysis of soils and sediments using well characterised procedures. However, difficulties can occur with samples such as unknowns containing small amounts of ore materials and samples collected from contaminated sites where trace elemental concentrations can exceed the concentration range for routine analysis. We studied the performance of a commercially available method, based on fundamental parameters (FP) to correct matrix effects. The spectrometer was originally calibrated with elemental or simple compound calibrants. Samples were analysed as pressed powder pellets. Eighteen sediment and soil reference materials, three of them with certified values for some of their constituents, were used to evaluate accuracy, by comparing results with recommended values and their standard deviations (RV ± 2s) or certified values and their confidence intervals (CV ± Cl). When results fell systematically outside these intervals, calibrations were refined with geochemical reference materials. The best agreement of results with recommended and certified values was obtained when the contents of H₂O and C in each sample were included as matrix constituents during calculations. The detection limits of trace elements tended to be relatively high, because the measuring conditions employed were not maximised for sensitivity. The main advantage of the method tested was that it enabled the analysis of samples with high concentrations of trace elements and the determination of elements such as F, Bi, Sb and W, which are not commonly included in quantitative XRF analysis of geological samples.     

Simultaneous determination of 37 elements in geochemical samples by spectrographic method using a specially designed covered electrode

Detection limits of volatile elements are effectively lowered by the spectrographic method of using covered electrodes in conjunction with the arc concentration technique; the method presented allows for simultaneous multi-element batch determination. In the author's laboratory, measurements were made by using a plane-grating spectrograph, PGS-2 with an a.c. arc generator as an excitation source and a current of 13 A. The detection limits of the 37 elements determined basically meet the needs of regional geochemical exploration with a relative standard deviation of ±5–10% for most elements (except B and Ga, which are ±10–20%). The analytical results of geochemical standard reference samples (GSD 1–8 of China and GXR 1–6 of the USGS) by this method agree with their recommended (or certified) values with a relative error of ±30%.     

New Series of Soil Geochemical Reference Materials (GSS 10-16) from the Main Overburden Region in China

Seven soil geochemical certified reference materials (CRMs) GSS 10-16 recently prepared by the Institute of Geophysical and Geochemical Exploration (IGGE), are mainly used for sample analysis in geochemical surveys of the overburden region in China. Fifteen Chinese institutes and central laboratories, which operated at a high level of analytical performance analysed these samples. More than ten reliable analytical methods based on different principles of measurement were adopted, of which ICP-MS, ICP-AES and NAA were taken as the primary analytical methods. In total, 23715 determinations were carried out, 5660 average data sets were obtained, seventy two elements and components were determined and certified values of sixty nine elements and components were assigned. Rhenium concentrations were measured by isotope dilution ICP-MS in GSS-10, GSS-13, GSS-15 and GSS-16. Certified values of elements in GSS 10-16 have good precision and for 90% of these values relative uncertainties are less than 10%.     

Sixteen Statistical Tests for Outlier Detection and Rejection in Evaluation of International Geochemical Reference Materials: Example of Microgabbro PM-S

A totally objective procedure involving sixteen statistical tests (a total of thirty four single or multiple outlier versions of these tests) for outlier detection and rejection in a univariate sample is applied to a data base of sixty four elements in a recently issued international geochemical reference material (RM), a microgabbro PM-S from Scotland. This example illustrates the relative importance and usefulness of these tests in processing modern geochemical data for possible outliers and obtaining mean concentration and other statistical parameters from a final normal sample of univariate data. The final mean values are more reliable (characterized by smaller standard deviations and narrower confidence limits) than those obtained earlier using an accommodation approach (robust techniques) applied to this data base. Very high quality (certified value equivalent, cve) mean data are now obtained for eleven elements as well as high quality recommended values (rv) for thirty three elements in PM-S. Earlier work using the accommodation approach failed to establish even one cve value for any of the sixty four elements compiled here. The present procedure of outlier detection and elimination is therefore recommended in the study of RMs     

Routine Control of Accuracy in Silicate Rock Analysis by X-Ray Fluorescence Spectrometry

In this study, we used the modified Horwitz expression (H_c= 0.01c^0.8495, which gives the precision as a function of concentration) to evaluate and control the accuracy of results of silicate rock analysis obtained by X-ray fluorescence spectrometry. This expression is currently used by the organisers of the GeoPT international proficiency tests, to assign the precision limits of each analyte and subsequently to evaluate the data provided by laboratories whose main application is geochemistry. Results for major and trace elements, determined in glass disk and pressed pellets, respectively, were evaluated. Nine international silicate rock reference materials were analysed and results were compared to the recommended values plus and minus the limits given by the above expression. Those limits are easily attained for most major elements, but not for trace elements. Sample preparation and sub-sampling contributions to precision were evaluated by analysis of an in-house reference sample. In our results, precision does not follow the Horwitz expression relationship with concentration. It is known that the final accuracy in XRF analysis depends strongly on instrumental settings and on the uncertainties associated with the certified or recommended values of the reference materials used to calibrate the spectrometer, but our results indicate that the precision expression can be useful, especially to inspect and correct calibration curves and to check routine instrumental accuracy.     

Preparation and Certification of Biogeochemical Reference Materials

The Institute of Geophysical and Geochemical Exploration in China recently prepared ten biogeochemical certified reference samples GSB1‐10 (CRMs). The samples are primary agricultural products such as rice, wheat, corn, soybean, cabbage, spinach, tea, powder, chicken and apple. Lyophilisation technology and a high‐alumina ball mill were used to process the samples. Fourteen laboratories and hundreds analysts in China participated in the certification analysis. Over ten reliable analytical methods, predominately ICP‐MS, ICP‐AES and INAA, were used for analysing the samples for fifty‐nine elements. A total of 22477 determinations led to 5136 average data sets. Certified values of fifty‐four elements were assigned.     

磷矿石化学成分分析标准物质研制

磷矿的开发与综合利用不仅需要分析磷等主要元素,也需要准确地测定稀土元素和微量元素。分析测试过程需要含量适中、定值组分全的磷矿石标准物质进行质量监控,国内外现有的磷矿石标准物质无论是从定值指标还是含量梯度范围等方面均无法满足此需求。本文研制了4个不同类型磷矿石成分分析标准物质。样品采集自河北张家口钒山磷矿、贵州织金新华磷矿、云南昆阳磷矿、湖北神农架火炼坡磷矿4个典型矿区,其中张家口钒山磷矿和织金新华磷矿为含稀土的磷矿。检验结果表明样品的均匀性、稳定性良好;通过11家实验室协作定值,定值元素包括造岩主量元素、稀土元素和痕量元素共37项,其中3个组分为参考值,其余均给出标准值和不确定度。4个磷矿石标准物质形成了一个从边界品位、工业品位到磷精矿较为完整的含量系列,P_2O_5的含量分别为10.57%、18.91%、27.78%、39.40%,稀土元素总量分别为0.16%、0.11%、0.032%、0.0083%,可满足磷矿勘查、评价和综合利用开发中对标准物质的需求。     

Mass Fractions of Forty‐Six Major and Trace Elements,Including Rare Earth Elements,in Sediment and Soil Reference Materials Used in Environmental Studies

Development of new techniques, enabling simultaneous determination of large numbers of elements in environmental samples, can force analysts to use certified reference materials that do not contain all the elements of interest. In this paper, the mass fractions of forty‐six major and trace elements, including rare earth elements (REE), are presented in one soil (NCS DC 77302 also known as GBW 07410) and five sediment (Metranal‐1, IAEA 405, MESS‐3, NCS DC 73309 also known as GBW 07311 and NCS DC 75301 also known as GBW 07314) certified reference materials determined by high resolution inductively coupled plasma‐mass spectrometry. The selected certified materials represent a spectrum of geological matrices often analysed in environmental studies. Measured elements include certified elements, elements listed with information values as well as new elements absent from certificates, including REEs and some other elements. REE + Y mass fractions in the river sediment reference material Metranal‐1 are reported for the first time. The results obtained are in agreement with available certified or information values.     

SLRS‐5 Elemental Concentrations of Thirty‐Three Uncertified Elements Deduced from SLRS‐5/SLRS‐4 Ratios

The fifth version of natural river water certified reference material, SLRS‐5 (National Research Council – Conseil National de Recherches Canada), is commonly used to control the quality of major and trace element measurements. Concentrations of silicon and thirty‐one uncertified trace elements have been reported for the certified reference material SLRS‐4, but they are not yet available for SLRS‐5. Here, SLRS‐5/SLRS‐4 ratios were deduced from SLRS‐5 and SLRS‐4 measurements by inductively coupled plasma‐atomic emission spectrometry and high‐resolution inductively coupled plasma‐mass spectrometry for certified elements and thirty‐five uncertified elements (rare earth elements, B, Bi, Br, Cs, Ga, Ge, Hf, Li, Nb, P, Pd, Rb, Rh, S, Sc, Si, Sn, Th, Ti, Tl, Y). Both reference materials were measured directly one after the other, so that calculated elemental ratios would not be notably influenced either by calibration uncertainties or by eventual long‐term instrumental drift. The computed ratios are in good agreement with those deduced from the certified values. We also report concentrations for thirty‐three uncertified elements in SLRS‐5 by combining the measured SLRS‐5/SLRS‐4 ratios and the published SLRS‐4 values. The resulting new data set provides target SLRS‐5 values, which will be useful in quality control procedures.     

岩石标准物质的研制

研制了霓霞正长岩，粗面岩，花岗闪长岩，辉长石，流纹岩及白云岩６种不同类型的岩石标准物质，对用Ｘ射线荧光光谱均匀性检验实际取样量进行了探讨，选择分析测试方法时，除采用了标准方法和长期应用的分析方法外，还采用了近年发展起来的新技术新方法，在定值中应用了多参数统计定值模式，给出了６９个元素的标准值和参考值，该批标准物质于１９９１年１月经国家技术监督局审核批准为国家一级标准物质，编号分别为ＧＢＷ０７１０９     

密闭高温高压溶样ICP-MS测定56种国家地质标准物质中的36种痕量元素——对部分元素参考值修正和定值的探讨

标准物质参考值的准确性在测试仪器校准、分析数据质量监控以及方法评价等方面具有非常重要的作用.为了检验国家地质标准物质参考值的准确性,本文应用高温高压密闭溶样-电感耦合等离子体质谱法分析了国家地质标准物质的18种岩石(GBW 07103 ～ GBW 07125)、19种沉积物(GBW 07301 ～ GBW 07318)和19种土壤(GBW 07401 ～ GBW 07430)中36种痕量与稀土元素.结果表明,除个别标准样品中的几个元素(Ni、Cr、Pb、Co、Cu、Sc、Yb、Lu)外,其余国家标准物质中36种元素测定结果的相对标准偏差均小于10％;绝大部分元素测定值的相对误差小于10％,测定值与参考值能较好地吻合.将误差较大元素的测定值与其他实验室的测定值以及文献报道值进行了比较,指出已有的参考值需要修正;针对部分沉积物和土壤中的元素未提供参考值,如GBW 07306的Ni、GBW 07313的Be、Hf、Ta,GBW 07314的Li、Be,GBW 07409、GBW 07410和GBW0741 1的Hf、Ta,GBW 07426的Gd、Ta,本文给出了相应的参考值.     

BAM‐S005 Type A and B: New Silicate Reference Glasses for Microanalysis

To test whether the silicate reference glasses BAM‐S005‐A and BAM‐S005‐B from BAM (The Federal Institute for Materials Research and Testing, Germany) are suitable materials for microanalysis, we investigated the homogeneity of these reference glasses using the microanalytical techniques EPMA, LA‐ICP‐MS and SIMS. Our study indicated that all major and most trace elements are homogeneously distributed at micrometre sampling scale in both types of glass. However, some trace elements (e.g., Cs, Cl, Cr, Mo and Ni) seem to be inhomogeneously distributed. We also determined the composition of BAM‐S005‐A and BAM‐S005‐B. The EPMA data of major elements confirmed the information values specified by the certificate. With the exception of Sr, Ba, Ce and Pb, our trace element data by LA‐ICP‐MS were also in agreement with the certified values within the stated uncertainty limits. The reasons for the discrepancy in these four elements are still unclear. In addition, we report new data for twenty‐two further trace elements, for which the concentrations were not certified. Based on our investigation, we suggest that both of these materials are suitable for many microanalytical applications.     

Report on the 2007 Recertification of the Certified Reference Materials GAS (Serpentinite) and OShBO (Alkaline Granite)

A report is presented on the recertification of two certified reference materials (CRMs) initially prepared and certified by the Central Geological Laboratory of Mongolia (CGL), namely serpentinite GAS and alkaline granite OShBO. Subsequent work done in collaboration with the International Association of Geoanalysts (IAG) followed the International Organisation for Standardisation (ISO) guidelines for certification (ISO Guide 35, 2006) more closely than had been possible originally. The certification protocol followed was that of the International Association of Geoanalysts (IAG). The recertification added to the number of elements that were certified for OShBO (from 21 to 30), but not for GAS (decreased from 15 to 12) because of the greater analytical difficulties posed by that sample matrix in meeting the more stringent metrological requirements for recertification. Further, the uncertainties for these values were established in accordance with the Guide to Measurement Uncertainty ; individual contributions of heterogeneity and bias are reported as appropriate for each of the certified constituents. Traceability of the certified values was demonstrated to the greatest possible extent, based on concurrent analyses of the matrix-matched existing CRMs, SW and GM, by all participating laboratories. The materials are now available from the CGL for use by laboratories in controlling data quality when analysing materials of similar matrices.     

中国火成岩化学元素的丰度与分布

在中国各构造单元构选采了１０３６４件火成岩样品合成１１３１个分析样，采用仪器中子活化法，Ｘ射线荧光光谱法，原子吸收法，原子荧光光谱法，催化波极谱法和分光光度法等１５种可靠分析方法进行测试，对一些难测痕量元素采用了最新的分析研究成果，以同类国家一级标准物质监控分析质量。     

The Preparation of Marine Geological Certified Reference Materials - Polymetallic Nodule GSPN-1 and Marine Sediment GSMS-1 from the Central Pacific Ocean*

This report describes the location, collection, preparation, homogeneity testing, analysis, data-processing and assignment of certified values of a polymetallic nodule (GSPN-1) and marine sediment (GSMS-1). Materials used in the preparation of these reference materials were collected in 1986 and 1987 from the central Pacific Ocean, by the Chinese Ministry of Geology and Mineral Resources (MGMR). A total of fifty one recommended element concentrations and five proposed concentrations are reported for GSPN-1. For GSMS-1, a total of fifty recommended and seven proposed values are presented.     

Recommended Radium-226 Values for Four CCRMP Uranium Reference Materials

The Canadian Certified Reference Materials Project announces recommended values for radium-226 activity in four reference materials previously certified for uranium. Thirteen laboratories participated in the interlaboratory program for DL-la, DH-la, BL-4a and BL-5. Four measurement techniques were applied. Procedural and instrument calibrations were performed with certified radium solutions from the National Bureau of Standards, thereby establishing traceability of the recommended values for radium-226 in DL-la, DH-la, BL-4a and BL-5. These reference ores are also shown to be close to, if not in, radioactive equilibrium.     

Recommended Lead-210 Values for Four CCRMP Uranium Reference Materials

The Canadian Certified Reference Materials Project reports recommended values of lead-210 activity in four uranium reference materials previously certified for uranium and radium-226. Eleven laboratories participated in the interlaboratory program for DL-1a, BL-4a, DH-1a and BL-5; three measurement techniques were applied. Procedural and instrumental calibrations were performed with a certified lead solution from Amersham International Corp., thereby establishing traceability of the recommended values for lead-210. Activity ratios for uranium-238. radium-226 and lead-210 demonstrate these uranium reference materials to be in secular equilibrium, within experimental uncertainties.     

Chemical Characterisation of NIST Silicate Glass Certified Reference Material SRM 610 by ICP-MS, TIMS, LIMS, SSMS, INAA, AAS and PIXE

National Institute of Science and Technology (NIST) silicate glass SRM 610 is widely used as a certified reference material for various micro-analytical techniques such as SIMS or laser ablation ICP-MS. SRM 610 has been nominally doped with sixty one trace elements at the 500 μg g⁻¹ level, but certified concentration data exist for only a few of these elements. This study reports concentration data for fifty nine trace elements obtained by ICP-MS, SSMS, LIMS, TIMS, INAA, AAS, and PIXE analyses of two different SRM 610 wafers. Most elements fall within a 10% band around a median value of about 440 μg g⁻¹. The REE concentrations are shown to be constant to 3% (1 σ), thus emphasizing the value of SRM 610 as a reference material for REE analyses.
Comparison of our values with published data suggests that different SRM 610 wafers are, within errors, chemically identical for most elements. Exceptions to this general rule appear to be restricted to elements which were partly lost during the production of the glass, e.g. Ag and Br. On the basis of six independent determinations of Rb concentrations, which are systematically lower by a few percent than the reported NIST value, we argue that the certified Rb concentration may not be representative for all distributed SRM 610 wafers.