低空白镍铳试金预富集中子活化分子测定地球化学标准物质中的铂族 …

研究了镍铳试金预富集中子活化分析测定岩石样品中的铂族元素。纯化捕集剂氧化镍,大大降低了化学分离全流程铂族元素的空白。取样量为５０ｇ时,所需溶剂各元素的空白值为（ｎｇ／ｇ）：Ｐｔ〈０．０５、Ｐｄ〈０．０５、Ｏｓ〈０．０１、Ｒｕ〈０．０５、Ｒｈ〈０．０５、Ｉｒ＝０．００２。用平面锗探测器测定Ｒｈ使测定下限降低了两个数量级。对几种国标地球化学标准物质的测定结果与推荐值基本符合。     

小锍试金铂族元素富集方法

研究了降低捕集剂镍用量的小铳试金铂族元素富集方法。通过测试,比较了重约０．５ｇ、２．５ｇ、２５ｇ试金扣的酸溶时间、铂族元素（ＰＧＥ）空白值。研究证明２．５ｇ试金扣既克服了常规试金扣和微型试金扣的缺点,又保留了它们的优点。经标准物质难证,铂族元素测定值与真值相符合。     

碱熔-电感耦合等离子体质谱法测定硫铁矿单矿物中的金、银及铂族元素

<正>单矿物分析在地质样品分析中属于较难解决的问题之一,原因是现成的分析方法少。而单矿物中微量元素的地球化学特征研究又需要矿物成分中微量元素含量的准确测定。铂族元素可以作为一种新的地球化学示踪剂,对岩石学特征和地幔源区的演化提供重要的信息。铂族元素通常采用火试金的方法测定[1-5],需要至少20g以上的样品,而单矿物的样品量通常比较少。这就要求用较少的试样量,不仅提供矿物主成分,而且要测定多种痕量元素,铂族     

铂族元素在环境和生物样品中的积累及毒性研究进展

由汽车尾气净化器的安装使用而导致环境中的铂族元素尤其是铂、钯、铑的含量逐渐增长,铂族元素对于生活和生态环境的影响也越来越多受到关注.论述了汽车三元催化剂中铂族元素毒性、铂族元素在环境和生物样品的分布、环境样品中铂族元素的消解、测定方法以及干扰处理方法,总结了多国测定结果并对结果进行了综合评述.     

锂盐-锍镍试金-等离子质谱法测定黑色页岩中铂族元素

建立锍镍试金-等离子质谱法测定黑色页岩中铂族元素(PGEs)的方法。在不减少称样量的前提下,结合黑色页岩成分特点,调整试金配料,利用硝酸钾的氧化性,解决形成锍扣难的问题;利用四硼酸锂的助融性,使盐酸溶解锍扣后黑色沉淀量大幅度降低,用等离子质谱法测定黑色页岩中铂族元素。PGEs的线性相关系数均不小于0.9995。Pt,Pd,Rh,Ir,Ru的检出限分别为0.30,0.36,0.032,0.028,0.041 ng/g。用该方法测定实际样品,测定值与参考值一致,测定结果的相对标准偏差为1.2%~10.6%(n=10)。该方法满足地质矿产实验室测试质量管理规范(DZ/T 0130-2006)的要求,可用于黑色页岩中铂族元素的测定。     

锍试金和锑试金富集贵金属 Ⅰ.光谱法测定铜镍硫化矿中的微量铂族元素

研究了用锍扣和锑扣试金富集贵金属,然后用光谱进行测定的方法,拟订了铜镍硫化矿中铂族元素分析的方案,矿石中的铂族元素先用锍扣捕集,酸处理除去贱金属硫化物,再经锑试金把铂族元素富集于毫克量的金属珠中进行光谱测定。一份取样和一次摄谱可以同时分析6个铂族元素。     

火试金预浓集结合中子活化和电感耦合等离子体质谱法测定铂族元素

建立了两种以火试金预浓集为基础的、可用于准确测定铂族元素的方法;中子活化法和电感耦合等离子体质谱法。讨论了它们的分析检出限、准确度及其适应性。并用这两种方法测定了5种候选地质参考物质中铂族元素的含量。     

沉淀分离-密闭消解-电感耦合等离子体质谱法测定铬铁矿中铂族元素EI北大核心CSCD

建立了沉淀分离-密闭消解-电感耦合等离子体质谱法测定铬铁矿中铂族元素的新方法。采用硫磷混酸溶样(1:2,V/V),以硫酸肼为还原剂,实现了硫脲对包括Os在内的全部铂族元素的沉淀富集,沉淀经密闭溶样技术快速消解后接ICP-MS测定。试验中筛选出HBr来消除Os的记忆效应,并考察了Os在王水介质中的稳定性。结果表明:铂族6个元素的线性相关系数均在0.999以上,对标准物质GBW07292平行测定6次的相对标准偏差(RSD,n=6)在2.7%~8.4%之间,方法检出限(3σ)在0.055~0.21ng/g,采用国家一级标准物质GBW07201,GBW07202,GBW07292进行方法验证,测定值与认定值基本一致。     

沉淀分离-密闭消解-电感耦合等离子体质谱法测定铬铁矿中铂族元素

建立了沉淀分离-密闭消解-电感耦合等离子体质谱法测定铬铁矿中铂族元素的新方法。采用硫磷混酸溶样(1:2,V/V),以硫酸肼为还原剂,实现了硫脲对包括Os在内的全部铂族元素的沉淀富集,沉淀经密闭溶样技术快速消解后接ICP-MS测定。试验中筛选出HBr来消除Os的记忆效应,并考察了Os在王水介质中的稳定性。结果表明:铂族6个元素的线性相关系数均在0.999以上,对标准物质GBW07292平行测定6次的相对标准偏差(RSD,n=6)在2.7%～8.4%之间,方法检出限(3σ)在0.055～0.21ng/g,采用国家一级标准物质GBW07201,GBW07202,GBW07292进行方法验证,测定值与认定值基本一致。     

电荷注入检测器电感耦合等离子体光谱仪测定铂族元素的性能

研究了用电荷注入检测器等离子体光谱仪测定铂族元素的分析性能。结果表明铂族元素有较好的检出限和10^4以上的线性动态范围，铂族元素间光谱干扰很少，在元素浓度＞1mg/L时测量精度可优于1％，钠对铂族元素的影响是轻微的。     

Determination of Ultra-Trace Platinum,Palladium, Ruthenium,Rhodium, and Iridium in Rocks and Minerals by Inductively Coupled–Plasma Mass Spectrometry Following Nickel Sulfide Fire Assay Preconcentration and Open Mixed Acid Digestion

Platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), iridium (Ir), and osmiun (Os) are platinum-group elements with similar physic-chemical properties, and have important applications in geochemistry and environmental chemistry. However, due to their low abundance and inhomogeneous distribution in natural ores as well as the nugget effect, the accurate determination of the platinum-group elements has been a challenge for geological analysis. In this work, self-prepared and purified sodium carbonate (NiCO₃) instead of commercial nickel oxide (NiO) was used as the fire assay collector in order to greatly reduce the reagent blank and method detection limits. In addition, the fuming time of HClO₄ was strictly controlled at 10?min and a high sensitive method was developed for the simultaneous determination of ultra-trace Pt, Pd, Ru, Rh, and Ir in minerals by inductively coupled plasma-mass spectrometry (ICP-MS) following preconcentration with the nickel sulfide fire assay. Under the optimized conditions, the linear ranges of Pt, Pd, Ru, Rh, and Ir were between 0 and 100?ng mL^?1, with correlation coefficients exceeding 0.9997. The detection limits were 0.015, 0.056, 0.014, 0.004, 0.012?ng mL^?1 (for 10?g sample) for Pt, Pd, Ru, Rh and Ir, respectively. The developed method was successfully applied to analyze Chinese Certified Reference Materials (CRMs) GBW07288, GBW07289, GBW07290, GBW07291, GBW07292, GBW07293, GBW07294, GBW07101, GBW07102 and GBW07201 and the determined values were in good agreement with the certified values. The relative standard deviations (n?=?5) of Pt, Pd, Ru, Rh and Ir were between 3.42% and 6.87% for the determination of GBW07291.     

The determination of platinum-group elements (PGE) by nickel sulfide fire-assay: Coexisting PGE-phases in the nickel sulfide button

The chemical composition of phases in buttons obtained by nickel sulfide fire-assay during the determination of platinum-group elements (PGE) has been investigated by electron microprobe analysis. Different PGE-containing phases, due to varying flux constituents and species of added PGE, have been detected. By using sodium tetraborate as flux constituent and adding PGE as chlorides, in a cryptocrystalline Ni₃S₂ matrix with low PGE (mainly Rh and Ru) contents, Rh- and Ru-bearing nickel sulfides ((Ni_7.68–7.80Ru_0.84–0.90Rh_0.35–0.43)₉S₈) and Ir alloys ((Ir,Pt,Os)_0.56–0.62(Ru,Rh)_0.25–0.28Ni_0.12–0.19) are found. Treatment with lithium tetraborate leads to a Ni₃S₂ matrix exhibiting slightly higher Rh and Ru contents, with inclusions of nickel-rhodium sulfides (Ni₈Rh₄S₉) and platinumnickel alloys (Pt_0.45Ni_0.36–0.39Ru_0.11–0.14Rh_0.05). Finely dispersed metallic colloidals from an automobile catalyst, with platinum and rhodium as main components, have given only platinum-nickel alloys (Pt_1–xNi_x). Considerable losses of PGE during analytical steps following the fire assay are expected when their contents in sulfidic phases, which are more likely to be dissolved, are high.     

Neutron activation analysis after a nickel sulphide fire assay preconcentration for determination of all platinum group elements in rocks

Neutron activation analysis after a nickel sulphide fire assay preconcentration for platinum group elements (PGE) has been established in our laboratory. In this work, the all PGE in DZ-2, a Chinese certified ultramafic rock standard reference material, are determined for testing the accuracy and precision of the method. The experimental conditions and the blank values from reagents and detection limits for the method are also presented.     

Application of NAA standardization methods using a low power research reactor

Two widely used neutron activation analysis (NAA) standardization methods (relative and k ₀) have been validated at the Ghana Research Reactor-1 (GHARR-1) Centre using environmental and biological standard reference materials (SRMs). The samples were IAEA Soil-7 as an environmental sample, and NIST Orchard Leaves 1571 as a biological sample. The qualitative and quantitative analyses were done using a high resolution Canberra N-type high purity germanium (HPGe) detector. The accuracy and precision were evaluated for the elements analysed. The concentrations of most of the elements were found to be within 10% of the certified values. Precision was calculated from six replicate measurements and was found to be within 15%.     

Analysis of large and non-standard geometry samples of ancient potteries by internal monostandard neutron activation analysis using in situ detection efficiency

The k ₀-based internal monostandard neutron activation analysis (IM-NAA) method was used for the analysis of 30 large and non-standard geometry ancient pottery samples obtained from Buddhist sites of Andhra Pradesh, India. One freshly finished pottery and a sun-drenched pottery were also analyzed for comparison. Samples were irradiated in thermal column facility of Apsara reactor and also in graphite reflector position of critical facility of Bhabha Atomic Research Centre. Radioactive assay was carried out using a 40% relative efficiency HPGe detector coupled to MCA. Concentration ratios of 15 elements with respect to Sc were determined. The La/Ce values as well as statistical cluster analysis utilizing concentration ratios of elements were used for grouping/provenance of the potteries.     

A standardless approach of INAA for grouping study of ancient potteries

The k ₀ based internal monostandard neutron activation analysis was used to analyze 41 ancient pottery samples from three major locations of Andhra Pradesh state, India, belonging to two different age groups namely Megalithic and Buddhist periods. Samples were irradiated with neutron flux obtained from CIRUS reactor and radioactive assay was carried out using a 40% relative efficiency HPGe detector coupled to 8?k MCA. Concentration ratios of 21 elements were calculated with respect to internal monostandard Sc. Absolute concentrations for six (three each from both Megalithic and Buddhist periods) representative samples along with a modern pottery were obtained for comparison. Elemental concentration ratios with respect to Sc were used for grouping of these archaeological samples. Preliminary grouping of these artifacts was done using La/Ce values, and the grouping was confirmed by statistical cluster analysis using eleven selected trace elements. The IAEA RM SL-3 sample was analysed for validation of the method, where in both concentration ratios and absolute concentrations were calculated.     

Monte Carlo and experimental efficiency calibration of gamma-spectrometers for non-destructive analysis of large volume samples of irregular shapes

A comparison of efficiency calibration of a HPGe gamma-ray spectrometer applied for non-destructive analysis of gamma-ray emitters in large volume samples of irregular shape is presented. The detector efficiency calibration was carried out during the analysis of cosmogenic radionuclides (⁶⁰Co, ⁵⁴Mn, ²²Na and ²⁶Al) in fragments of the Ko?ice meteorite. Fourteen meteorite fragments were available for the analysis with masses from 27 to 2,163 g. A reasonable agreement in the estimation of the HPGe detector efficiency was obtained using the Monte Carlo simulation GEANT 3 code, and the experimental calibration using radioactive standards mixed with iron–silica–copper powder housed in mock-ups of similar shapes as the original samples. The differences in the efficiency estimation obtained by both methods were within 10 %. It is recommended that the Monte Carlo simulation of the detector efficiency can be applied in routine analysis of gamma-ray emitters in large volume samples of regular or irregular shapes.     

An innovative Compton suppression spectrometer and its capability of evaluation in multi-elemental neutron activation analysis

A new Compton suppression system was established. A low energy HPGe detector (LO-AX) is used as the analyzing detector. It is completely shielded by a 50%n-type HPGe and two NaI(TI) detectors. Experiments show that a substantial Compton suppression effect is also achieved in the low energy region down to 15 keV. The capability of applying this system in INAA was evaluated for 13 elements (As, Cd, Co, Cr, Hg, Mo, Ni, Sb, Se, Sr, Th, U and Zn) in biological and environmental samples. The benefits and problems of using this Compton suppression spectrometer in INAA are examined for each element.     

Compton suppression system at Penn State Radiation Science and Engineering Center

A Compton suppression system is used to reduce the contribution of scattered gamma-rays that originate within the HPGe detector to the gamma-ray spectrum. The HPGe detector is surrounded by an assembly of guard detectors, usually NaI(T1). The HPGe and NaI(T1) detectors are operated in anti-coincidence mode. The NaI(T1) guard detector detects the photons that Compton scatter within, and subsequently escape from the HPGe detector. Since these photons are correlated with the partial energy deposition within the detector, much of the resulting Compton continuum can be subtracted from the spectrum reducing the unwanted background in gamma-ray spectra. A commercially available Compton suppression spectrometer (CSS) was purchased from Canberra Industries and tested at the Radiation Science and Engineering Center at Penn State University. The PSU-CSS includes a reverse bias HPGe detector, four annulus NaI(T1) detectors, a NaI(T1) plug detector, detector shields, data acquisition electronics, and a data processing computer. The HPGe detector is n-type with 54% relative efficiency. The guard detectors form an annulus with 9-inch diameter and 9-inch height, and have a plug detector that goes into/out of the annulus with the help of a special lift apparatus to raise/lower. The detector assembly is placed in a shielding cave. State-of-the-art electronics and software are used. The system was tested using standard sources, neutron activated NIST SRM sample and Dendrochronologically Dated Tree Ring samples. The PSU-CSS dramatically improved the peak-to-Compton ratio, up to 1000:1 for the ¹³⁷Cs source.