氢化物发生-原子荧光光谱法直接测定多金属矿中的硒和碲

用硝酸-氢氟酸-高氯酸分解多金属矿物样品,在6 mol/L盐酸介质中,以Fe3+盐为减缓剂,直接在双道原子荧光光度计上同时测定多金属矿中硒和碲。该方法用同一混合酸一次分解样品,不经分离富集,同时测定硒和碲,过程简单快捷,适合于批量样品的检测。将样品与标准曲线同时分解至冒高氯酸白烟,从而准确地测定多金属矿物样品中硒和碲的含量。方法检出限为硒0.032μg/g,碲0.023μg/g;方法精密度(RSD,n=8)为硒<4.0%,碲<7.0%。经国家一级标准物质GBW 07283、GBW 07233、GBW 07234验证,硒和碲的测定值与标准值吻合。     

氢化物发生-原子荧光光谱法测定生物样品中的硒

用硝酸-高氯酸分解生物样品,在4 mol/L盐酸介质中,加入一定浓度的三价铁盐作为掩蔽剂抑制干扰元素,用氢化物发生-原子荧光光谱法测定生物样品中微量硒的含量。方法检出限为0.02μg/L,精密度(RSD,n=11)为1.51%。经国家一级生物标准物质验证,测定结果准确可靠。方法具有操作简单、灵敏度高、线性范围宽等优点,所用试剂毒性小,实用性强,适合广泛使用。     

Determination of Platinum-Group Elements and Gold in Geological Matrices by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) after Separation with Selenium and Tellurium Carriers

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.     

土壤硒的存在特征及分析测试技术研究进展

硒是重要的生命健康微量元素之一,土壤硒的空间异质性是造成各种病害和环境问题的主要原因.全球土壤硒分布不均匀,大部分属于低硒土壤,土壤硒含量平均值为0.4mg/kg,典型高硒地区土壤硒含量为346～2018 mg/kg.准确分析土壤硒含量是开展土壤硒研究的基础,土壤样品来源特征和硒存在形式是土壤硒分析测试方法的选择依据,...     

风化过程中硒背景值的定量表征

硒是人和动物必需的微量元素,基于58件标准物质的化学风化指标和硒的认定值,采用微量元素地球化学背景值的经验方程形式拟合得到表征全国范围内硒背景值的经验方程：lgc=0822×(12-WIG/100)-1061×lg(K2O/SiO2)-2704,式中c为Se的含量(单位为μg/g),风化指标WIG的变化范围为43~1116,风化指标K2O/SiO2变化范围为0020~0137。该方程所表征的是样品因风化程度不同所呈现出的硒地球化学背景值,风化程度强的样品总体上具有较高的Se地球化学背景值。将该经验方程式在广东河台和广东南昆山两个研究区进行应用,认为寻找富硒区应当优先将风化程度较强的地区视为备选区,依据全国区域化探扫面数据可以方便地确定风化程度较强的地区。在环境质量评价中可以利用Se实测值确定足硒和富硒区,利用实测值扣除背景值获得的元素含量剩余值可以有效确定残积层土壤下伏的足硒和富硒岩石,即依据全国多目标地球化学调查数据可以有效地确定足硒和富硒地质体(残积层土壤及其下伏岩石)的分布区。广东南昆山岩体中西部的岩石应属于足硒和富硒地质体。     

Selenium Content of Geochemical Reference Samples Determined by a Simple Method at ng/g Level

Nine geochemical reference samples from various sources were analyzed for selenium. The method used was simplified with regard to the decomposition and selenium isolation from matrix. Selenium was determined by hydride-generation atomic absorption; after selenium isolation from the matrix no interferences are to be expected. The results are in good agreement with values obtained by other methods.     

Selenium Concentrations in Twenty-Six Geological Reference Materials: New Determinations and Proposed Values

The interest in selenium concentrations in whole rocks is growing, in part because it is a useful tool for base and precious metal exploration. Selenium is often neglected in whole rock geochemistry because of the inability of most laboratories to make reliable determinations of this element. A consequence of these difficulties is a paucity of assigned or certified values for Se in international geological reference materials, so that the "best practice" proposed by Kane and Potts (2007) to obtain robust values for such reference materials cannot be followed. In order to address this problem, we have determined Se by pre-concentration on thiol-cotton fibre followed by INAA (Se/TCF-INAA technique) in twenty-six international geological reference materials, and one quality control material (KPT-1). These values were used, in conjunction with a set of published values, to estimate Se concentrations for these twenty-seven reference samples. Robust statistics were developed for seven of the RMs, with standard deviations equal to or less than precisions calculated using the Horwitz function and so that consensus values could be proposed. For three of the RMs, the presence of outliers gave less robust results, and suggested values are proposed. For seventeen of the RMs, only information values are provided, because either insufficient determinations were available or because large standard deviations of the data were derived.     

Preparation and Certification of Reference Materials (GBW07397, GBW07398, GBW07399 and GBW07400) for Selenium and Other Trace Element Mass Fractions

The preparation and characterisation of certified reference materials of four selenium‐rich rocks (GBW07397 to GBW07400) are described in this paper. The raw materials were derived from selenium‐rich rocks in two famous seleniferous regions, Enshi Prefecture, Hubei Province and Ziyang County, Shaanxi Province, China. Sample homogeneity and stability were tested by inductively coupled plasma‐mass spectrometry and atomic fluorescence spectrometry. The determined element mass fractions included selenium, arsenic, copper, zinc, molybdenum, cadmium, lead, vanadium and silver. Except for silver, the results of analysis of variance (ANOVA) and the relative standard deviations of the element mass fractions showed that the four materials exhibited good homogeneity and stability. Ten laboratories were involved in an interlaboratory comparison scheme for certification. Eight element mass fractions in the selenium‐rich rocks were assigned as certified values, while only indicative values were obtained for Ag mass fractions. The certified values and expanded uncertainties for the selenium mass fractions in GBW07397–GBW07400 are 0.96 ± 0.05, 1.03 ± 0.05, 49 ± 4 and 38.5 ± 1.9 μg g^?1, respectively.     

地质标准物质不确定度评估方法初探

在分析地质标准物质标准值不确定度来源的基础上,提出了在多个实验室协作研制地质标准物质时,协作单位除提供重现性检测数据外,还应分别提供各项目检测数据的合成不确定度。分析方法或实验室之间的平均值的合成不确定度按不等精度方法处理。标准物质标准值的不确定度由分析方法、检测实验室、样品均匀性和样品稳定性的不确定度合成后乘以扩展不确定度置信水平下的包含因子而得。     

焙烧分离-氢化物发生-原子荧光光谱法测定土壤样品中微量硒

采用艾斯卡试剂(碳酸钠和氧化锌)作焙烧试剂,半熔法分解样品,沸水提取,分离出Cu、Co、Ni等过渡金属元素,氢化物发生-原子荧光光谱法测定土壤样品中微量硒。通过正交试验确定了测定方法的仪器和试剂条件,考察了Cu、Ni、Fe、Al、Pb、Au、As、Bi、Sb、Pt等共存元素的干扰情况。方法检出限为0.0135μg/g,回收率为87.0%~123.0%。对多个土壤国家一级标准物质进行测定,其结果与标准值相符。方法同时适合于地质样品及多金属矿中硒的测定。     

Production and Certification of Synthetic Selenium Isotopic Reference Materials

Due to intensive research into selenium isotopes in recent years, the increasing requirement for reliable and comparable measurement results has created a strong demand for selenium isotopic certified reference materials (iCRM) that were previously not available. To address this, eleven selenium iCRMs were developed, including ten synthetic iCRMs (GBW 04447–GBW 04456) and one natural iCRM (GBW 04457). The synthetic iCRMs were prepared with ⁷⁶Se, ⁷⁸Se, ⁸⁰Se and ⁸²Se solutions and a natural selenium solution; the natural iCRM was prepared with highly pure selenium material. The property values of isotope ratios in these iCRMs were certified by calibrated mass spectrometry with a collision cell multi‐collector ICP‐MS. The mass discrimination effect of the instrument was corrected with corresponding ⁷⁸Se/⁷⁶Se isotope mixtures and ⁸²Se/⁷⁶Se isotope mixtures, which were gravimetrically prepared with purified, isotopically enriched selenium materials. Homogeneity and stability tests were performed, and no significant influences were found. The uncertainty of the property values of the iCRMs was evaluated according to the Guide to the Expression of Uncertainty in Measurement (GUM) of ISO/BIPM and ISO Guide 35. The δ^82/76Se value of GBW 04457 relative to NIST SRM 3149 was also calculated. These iCRMs are intended for use in calibration of instruments and evaluation of methods for the determination of selenium isotope ratios.     

金标样定值中全金量的湿法分析

含金试样经王水溶解,溶液经活性炭吸附-碘量法测定溶液中的金;残渣经氢氟酸和王水再溶解,活性炭富集-火焰原子吸收测定残渣中的金;两项结果相加作为样品中金的总量。方法用于金的地质标样定值分析,结果与标准值吻合(E<3s)。     

Sequential Inductively Coupled Plasma Determination Of Some Rare-Earth Elements in Five French Geostandards

Experimental data for eleven rare-earth elements (REE) obtained by inductively coupled plasma spectrometry (ICP) in five French geochemical reference standards (BE-N, BR, DR-N, GS-N and FK-N)are presented. The method is based on acid digestion of the sample and cation-exchange separation from matrix elements.
Together with these new determinations an updated compilation of these reference materials are presented. Good agreement between the present results and previously preferred and published values obtained by various analytical techniques is observed. The values obtained in the present work corroborate the validity of the outlined method.     

Determination of Total Sulfur in Fifteen Geological Materials Using Inductively Coupled Plasma‐Optical Emission Spectrometry (ICP‐OES) and Combustion/Infrared Spectrometry

A method for the determination of total sulfur in geological materials by inductively coupled plasma‐optical emission spectrometry (ICP‐OES) is described. We show that good results were obtained using this method even for sample types with very low (< 20 μg g^?1) sulfur concentration (e.g., peridotite). Sulfur was determined in fifteen geological reference materials with different sulfur contents. For reference materials with certified sulfur contents, the ICP‐OES method gave results in excellent agreement with certified values, and uncertainties better than 4% RSD. ICP‐OES results for sulfur in other reference materials yielded RSDs better than 10%, where S concentrations were > 100 μg g^?1 (except for diabase W‐2a, 16% RSD). Reference materials with lower sulfur contents (< 40 μg g^?1) showed much higher RSDs (17–18%). Except for RMs with certified values for sulfur, most data obtained by the combustion infrared detection method generally showed higher concentrations than those measured by ICP‐OES and a better RSD (≤ 8% for all materials except DTS‐2b).     

地球化学与环境样品分析标准物质和GeoReM数据库

在地球化学和环境样品分析中,标准物质发挥着越来越重要的作用。尽管通常要求分析者必须提供量值溯源的测量过程的信息;但大多数论著都未给出标准物质的数据。文章强调标准物质在地球化学分析工作中的重要性,同时将地球化学与环境样品分析标准物质数据库GeoReM介绍给中国的地质分析工作者。GeoReM数据库收录了1880个地球化学和环境样品分析标准物质的定值数据、汇编数据、分析数据及其他相关信息,其中包括156个由中国制备的标准物质的数据。GeoReM数据库还给出了所收录标准物质推荐使用的首选值及其不确定度。尽管这些首选值大多都不是按照国际标准化组织的有关规定而确定的,但是它们的置信度高,因而被广泛应用于仪器校准和分析数据的质量监控。文章还指出要将中国研制的、发表在中文期刊上的标准物质也收录到GeoReM数据库中,这对于促进中国的相关研究,增加国际认可度具有重要意义。     

Determination of Selenium and Tellurium in Basalt Rock Reference Materials by Isotope Dilution Hydride Generation-Inductively Coupled Plasma-Mass Spectrometry (ID-HG-ICP-MS)

Promising methods have been developed recently for the determination of selenium (Se) and tellurium (Te) in geological materials at ng g⁻¹ and lower levels, using hydride generation-inductively coupled plasma-mass spectrometry. Here we report on a new isotope dilution-hydride generation-inductively coupled plasma-mass spectrometry (ID-HG-ICP-MS) method for the simultaneous determination of Se and Te, which is applied to basalts, and modified compared to previous work. The basalts were attacked and dissolved with hydrofluoric and nitric acid, spiked with enriched isotopes, and passed through a cation exchange column (AG 50-X8 100–200 mesh) to separate the major cations that interfere with Se and Te detection (e.g., Fe). The detection limits of this method were 0.010 ng g⁻¹ for Se and 0.0030 ng g⁻¹ for Te, well below the concentrations of Se and Te expected in basalts. The precision of the method for Se was 12.2 to 15.1% and for Te was 4.6 to 7.2% RSD from replicate analyses of basalt reference samples. The accuracy for Se determinations was 61 to 94% and for Te 28 to 100% of values previously reported in the literature for selected USGS reference materials.     

Determination of the Platinum-Group Elements and Gold in Twenty Rock Reference Materials by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) after Pre-Concentration by Nickel Sulfide Fire Assay

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.     

Sulfur Concentration in Geochemical Reference Materials by Solution Inductively Coupled Plasma‐Mass Spectrometry

With implications for the origin of ore deposits, redox state of the atmosphere, and effects of volcanic outgassing, understanding the sulfur cycle is vital to our investigation of Earth processes. However, the paucity of sulfur concentration measurements in silicate rocks and the lack of well‐calibrated reference materials with concentrations relevant to the rocks of interest have hindered such investigations. To aid in this endeavour, this study details a new method to determine sulfur concentration via high mass resolution solution inductively coupled plasma‐mass spectrometry (ICP‐MS). The method is based on an aqua regia leach, involving relatively rapid sample preparation and analysis, and uses small test portion masses (< 50 mg). We utilised two independently prepared standard solutions to calibrate the analyses, resulting in 4% accuracy, and applied the method to eight geochemical reference materials. Measurements were reproducible to within ~ 10%. Sulfur concentrations and isotopes of six reference materials were measured additionally by elemental analyser‐combustion‐isotope ratio mass spectrometry to independently evaluate the accuracy of the ICP‐MS method. Reference materials that yielded reproducible measurements identical to published values from other laboratories (JGb‐1, JGb‐2 and MAG‐1) are considered useful materials for the measurement of sulfur. Reference materials that varied between studies but were reproducible for a given test portion perhaps suffer from sample heterogeneity and are not recommended as sulfur reference materials.     

Multi-Element Isotope Dilution Sector Field ICP-MS: A Precise Technique for the Analysis of Geological Materials and its Application to Geological Reference Materials

We present a multi-element technique for the simultaneous determination of twelve trace elements in geological materials by combined isotope dilution (ID) sector field inductively coupled plasma-mass spectrometry (SF-ICP-MS) following simple sample digestion. In addition, the concentrations of fourteen other trace elements have been obtained using the ID determined elements as internal standards. This method combines the advantages of ID (high precision and accuracy) with those of SF-ICP-MS (multi-element capability, fast sample processing without element separation) and overcomes the most prevailing drawbacks of ICP-MS (matrix effects and drift in sensitivity). Trace element concentration data for BHVO-1 (n = 5) reproduced to within 1–3% RSD with an accuracy of 1–2% relative to respective literature values for ID values and 2–3% for all other values. We have applied this technique to the analysis of seventeen geological reference materials from the USGS, GSJ and IAG. The sample set also included the new USGS reference glasses BCR-2G, BHVO-2G and BIR-1G, as well as the MPI-DING reference glasses KL2-G and ML3B-G, and NIST SRM 612. Most data agreed within 3–4% with respective literature data. The concentration data for the USGS reference glasses agreed in most cases with respective data of the original rock powder within the combined standard uncertainty of the method (2–3%), except the U concentration of BIR-1G, which showed a three times higher concentration compared to BIR-1.     

珠江三角洲沉积物标准物质研制

为满足近海地球化学调查及资源勘探的需要,研制了3个珠江三角洲沉积物标准物质.样品经干燥、球磨至200目,采用XRF法进行均匀性检验,结果显示方差检验的F实测值均小于列表临界值,证明样品具有较好的均匀性.在2年时间内选取有代表性的元素进行了4次稳定性测试,结果表明样品稳定性良好.共12家实验室参加了合作定值,采用了16种准确可靠的分析方法,最终定值元素70项.该标准物质的研制将为河口三角洲地区地质调查提供可靠的质量保证.