石煤钒矿成分分析标准物质的研制

石煤钒矿资源的开发和合理利用需要对其成分进行准确的分析测试和质量控制.目前,国内外尚未有石煤钒矿成分分析的标准物质,现有钒成分分析标准物质无论是其五氧化二钒含量,还是定值成分都无法满足我国对石煤钒矿勘查、开发和研究需要.本文对采自湖北省崇阳县小源冲钒矿、湖南省芷江县牛牯坪钒矿、湖南省古丈县岩头寨钒矿和湖南省凤凰县黑冲钒...     

Determination of Halogens (F, Cl, Br, I), Sulfur and Water in Seventeen Geological Reference Materials

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.     

Use of Chelating Resin YPA4 Micro-Columns for the On-Line Preconcentration and Separation of Gold(III), Silver(I), Palladium(II) and Platinum(IV) in Geological and Environmental Samples and Their Determination by Inductively Coupled Plasma-Atomic Emission Spectrometry

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.     

Flotation Separation of Trace Elements from Alkaline-Earth Matrices by Co(III) Hexamethylenedithiocarbamate before ICP-AES Determination

A method for the selective separation of Ag, Cd, Cr, Cu, Ni, Pb and Zn in traces from solutions of calcite (CaCO₃), dolomite (CaMg(CO₃)₂) and gypsum (CaSO₄.2H₂O) before their determination by inductively coupled plasma-atomic emission spectrometry (ICP-AES) is presented. The expected interferences of Ca and Mg on intensities of trace analytes were removed by collecting the elements of interest with cobalt(III) hexamethylenedithiocar-bamate, Co(HMDTC)₃. The flotation of aqueous solutions (1 l) of calcite, dolomite and gypsum was performed at pH 6.0, by 1.5 mg l⁻¹ Co and 0.6 mmol l⁻¹ HMDTC⁻. To minimise the effect of the reaction between Ca/Mg, which restrains the function of the surfactant, careful selection of the most suitable foaming reagent was necessary. The accuracy of the method was established by analysing natural alkaline-earth minerals by the standard addition method as well as using the dolomite reference materials GBW 07114 and GSJ JDo-1. The ICP-AES limits of detection following flotation on different minerals were found to be 0.080 μg g⁻¹ for Cd, 0.105 μg g⁻¹ for Ag, 0.142 μg g⁻¹ for Cu, 0.195 μg g⁻¹ for Cr, 0.212 μg g⁻¹ for Ni, 0.235 μg g⁻¹ for Zn and 0.450 μg g⁻¹ for Pb.     

黔东注溪黑色岩系地球化学特征及矿化富集规律

目前急需分析黔东注溪钒矿形成的环境、成矿的物质来源以及矿化富集规律,指导实际地质勘查工作.系统研究了注溪矿区内中洞、老屋基和坪哨3个典型岩性剖面中黑色岩含矿岩系及矿层的全岩主微量元素组成.结果表明,含矿岩系具有较高的SiO₂、MnO、Ce/Ce*和Eu/Eu*值,而矿层则含相对较高的Al₂O₃、Fe₂O₃、TiO₂、CaO、Na₂O、K₂O、P₂O₅、V₂O₅、REE、As、Cu、Pb、Zn、Mo、Ni、Ti、Cr、Rb、Sr、Th、U和V.含矿岩系与矿层的主微量地球化学特征显示注溪钒矿床的成矿物源具有一定程度陆源物质的输入,且在成矿阶段受到了热水作用及生物作用的影响.另外,由南至北各剖面的热水成矿作用逐渐减弱;含矿岩系及矿层沉积环境均属缺氧环境,其中坪哨剖面的矿层沉积环境的缺氧程度要高于其他剖面.因此,注溪钒矿床钒富集成矿主要受古环境的还原条件和热液活动的影响,其中还原环境对钒元素的富集成矿起主要作用.据此推测坪哨剖面矿层形成时的海水深度应最深,北矿段中洞剖面的最浅;喷流热水带来的V等大量多金属元素在喷口及其附近大规模成矿.      

新显色剂5-(5-氟-2-吡啶偶氮)-2,4-二氨基甲苯的合成及其与钯的显色反应

合成并用红外光谱和元素分析鉴定了氟代吡啶偶氮氨类新试剂5-(5-氟-2-吡啶偶氮)-2,4-二氨基甲苯(5-F-PADAT),并研究了该试剂与钯显色的反应。结果表明,在0.32~3.84 mol/L高氯酸溶液中,试剂与钯形成1∶1的紫红色络合物,其最大吸收峰位于566 nm,表观摩尔吸光系数为4.84×104L.mol-1.cm-1,钯的浓度在0~2000μg/L符合比耳定律。方法选择性好,大量常见金属离子不干扰钯的测定,操作简单,应用于矿样和催化剂中微量钯的测定,结果与原子吸收光谱法相符。     

Determination of Platinum and Palladium in Geological Samples by Inductively Coupled Plasma-Atomic Emission Spectrometry after Preconcentration with Immobilised Nanometric Titanium Dioxide

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.     

Determination of Rare Earth Elements and Y in Ultramafic Rocks by ICP-MS After Preconcentration Using Fe(OH)3 and Mg(OH)2 Coprecipitation

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%.     

Mineralizations of Base Metal Deposits of Acid-Sulfate Type Coexisting with Adularia-Sericite Type

Abstract: Two types of ores are recognized in the Huanzala mine, Peru. Zinc and lead ore of adularia-sericite type, is accompanied by pyrite body and skarn. Orthoclase (adularia), sericite and calcite are found in the skarn and altered country rocks. On the other hand, copper and silver (tin) ore of acid-sulfate type, is characterized by enargite, luzonite and bornite, accompanied by tin, silver and tellurium minerals. Although sericite and calcite are found only at the earlier stage in the mineralization of acid-sulfate type, kaolinite appears in the country rocks at a subsequent stage. It is interpreted that the ore-forming fluid of the acid-sulfate type separated from the adularia-sericite type by boiling in the early stage of mineralization. The separated fluid was nearly neutral just after boiling and changed into acidic by the oxidation of H₂S into HSO₄^-. Both types of mineralizations are studied in terms of fo₂-fs₂-pH-temperature diagrams. The adularia-sericite type might correspond to the hot-water system of a geothermal area, and the acid-sulfate type to the vapor-dominated system.
The copper ores from the Teine mine, Hokkaido, Japan and the Chinkuashih mine, Taiwan are acid-sulfate type, characterized by the occurrence of enargite and luzonite. However, zinc and lead ores of the adularia-sericite type are also present in these deposits. Both types in the Teine and Chinkuashih deposits are supposed to have formed in the similar relation as in the Huanzala deposits. The enargite and luzonite ores in the Hokuetsu mine, Japan are closely associated with native sulfur of solfataric origin.     

Synthetic Fluid Inclusions in the Systems NaCl-H2O and NaCl-CO2-H2O: Dissolution Temperatures of Halite

Abstract. This study examined the effect of CO₂ on NaCl solubility in hydrothermal fluid, with the synthetic fluid inclusion technique. Fluid inclusions of 30–40 wt% NaCl and 5 mol % CO₂ were synthesized, and their halite dissolution temperatures, T_m(halite), were measured. The solubilities of NaCl in CO₂-bearing aqueous fluid were obtained at 160–320C under vapor-saturated pressures. The T_m(halite) value in aqueous fluid with 5 mol % CO₂ obtained in this study agrees with that of Schmidt et al. (1995), showing that 5 mol % CO₂ reduces the solubility of NaCl by about 1 wt%.
Calculation of magnetite solubility suggests that 5–10 mol % CO2 decreases magnetite solubility by 4.5–8.9 % relative to the magnetite solubility in CO2-free solution. Therefore, an increase of CO2 content in ore-forming solutions may cause deposition of iron minerals and produce ore deposits.     

Alkali feldspars as a main phosphorus reservoirs in rare-metal granites: three examples from the Bohemian Massif (Czech Republic)

Phosphorus-rich alkali feldspars were found in three peraluminous highly differentiated albite-topaz-Li-mica granites in the W and S parts of the Bohemian Massif. The average contents of P₂O₅ in K-feldspars (Křížovy kámen 0.57 wt%, Homolka 0.77 wt%, and Podlesí 0.83 wt%) are higher than the average contents of P₂O₅ in albites (Křížovy kámen 0.23 wt%, Homolka 0.23 wt%, and Podlesí 0.39 wt%). The analyses of feldspars indicate that partition coefficient of phosphorus between K-feldspar and albite range from 1.5 to 2.5. Measured data in K-feldspars suggest a statistically significant difference from the Al³⁺+P⁵⁺=2 Si⁴⁺ substitution mechanism for higher phosphorus concentration. The P-content in K-feldspars from the Podlesí-granite represent the highest P-content in natural feldspar known to date (up to 2.5 wt% of P₂O₅)- It is suggested that all studied granites retained nearly all phosphorus of granitic melts and that their alkali feldspars represent major reservoirs of phosphorus.     

Role of Iron(III) and Aluminum Hydroxides in Concentration/reduction of Au(III) Complexes

Abstract: The adsorption of gold on iron(III) and aluminum hydroxides from solutions containing Au(III) complexes has been studied as a function of pH and chloride concentration at 30C. Iron(III) hydroxide was more effective in adsorbing gold from solution than aluminum hydroxide. However, both hydroxides controlled the behavior of Au(III) complex with very similar manner. The most effective gold adsorption occurred in aqueous solution with near neutral pH and low Cl concentration. In this solution condition, Au(III) complexes were mainly dissolved as AuCl₂(OH)₂^- and AuCl(OH)₃^-, and the surface charge for both hydroxides was positive. In addition, the adsorbed Au(III) complexes were spontaneously reduced to elemental gold in spite of the absence of a specific reducing agent.
The results of this study suggest that adsorption and spontaneous reduction of gold complexes on the surface of hydrous metal oxides with positive charge play an important role in gold precipitation in subsurface environment.     

The Fluid Evolution Related to Talc Mineralization in the Hwanggangri Area, South Korea

Abstract: Scores of talc deposits distributed in the Hwanggangri Mineralized Zone, South Korea are interpreted to have resulted from the contact metamorphic process related to the igneous intrusion of the Muamsa Granite. Talc usually occurs as an alteration product from tremolite, which is crystallized during the prograde stage. It commonly forms fine–grained, fibrous aggregates, or pseudomorphs after tremolite, and abundant tremolite is included as impurities in the talc ore. Quantitative X-ray diffraction analysis has shown that the ores can be divided into three types depending on the concentrations of talc; talc-tremolite ore (talc > 50 %), tremolite-talc ore (10 % < talc < 50 %), and tremolite (talc < 10 %) ores. Oxygen isotope compositions of those talc ores become higher from 10.9–12.1 through 11.6–12.3 to 11.9–13.2% with increasing tremolite concentrations, while hydrogen isotope compositions are not so variable, –73 to –69%. The high value of the calculated δ¹⁸O_H2O of the fluids equilibrated with the tremolite may have resulted from the mixing of magmatic water with ¹⁸O–enriched CO₂ evolved from the decarbonation reaction during the prograde stage. However, as the decarbonation reaction ceased during the retrograde stage, the inferred oxygen isotope compositions of talc-forming fluids show similar values to those of the igneous fluids.     

Observations on New Approaches for the Determination of Platinum-Group Elements, Gold and Silver in Different Geochemical Samples from Siberia and the Far East

Some recent experiments on the determination of Au and the platinum-group elements (PGE) in geochemical samples are reviewed. Emphasis is given to the determination of ultra-low levels of PGE concentrations in resistant matrices, including chromites, molybdenites and ultrabasic ores. The problems and features of PGE determination in samples of various chemical composition are considered. For each sample type studied, a series of sample preparation techniques are proposed. These techniques included acid digestion, fusion with sodium peroxide, cold sintering with an oxidizing mixture of Na₂O₂+ Na₂CO₃ and also oxidizing fluorination with bromine trifluoride. A new approach for preparing geochemical material prior to digestion, based on mechano-chemical activation with simultaneous hyperfine grinding, is proposed and studied. The instrumental determination of PGE contents was carried out directly by AAS from extracted organic phases. It was found that a combination of digestion processes was required to achieve geochemical background levels of Au and PGE concentrations with the following detection limits: Pd, Rh - 1 ng g⁻¹, Pt, Ru - 10 ng g⁻¹, Au - 0.2 ng g⁻¹, Ag - 0.1 ng g^−1. The uncertainty in PGE and Au determination in geochemical samples is dependent on metal concentration, and also on their distribution in samples. The total analytical uncertainty of the proposed method is between 15-30%.     

Transformation of magnetite to hematite and its influence on the dissolution of iron oxide minerals

Deformed rocks of the Itabira Iron Formation (itabirites) in Brazil show microstructural evidence of pressure solution of quartz and iron oxides; it appears that magnetite was dissolved and hematite precipitated. The dissolution of magnetite seems to be related to its transformation to hematite by oxidation of Fe²⁺ to Fe³⁺. The transformation of magnetite to hematite occurs along {111} planes, and results in the development of hematite domains along {111} that are parallel to the foliation. The difference in volume created by the transformation of magnetite to hematite and the shear stress acting on the interphase boundaries allow fluids to migrate along these planes. The dissolution of magnetite involves the hydrolyzation of the Fe²⁺—O bonds at interphase boundaries of high normal stress. The high fugacity of oxygen in the fluid phase promotes the reaction of Fe²⁺ (in solution) with oxygen. Fe²⁺ ions oxidize to Fe³⁺ and precipitate as hematite platelets with their longest axes oriented parallel to the direction of maximum stretching. The transformation of magnetite to hematite during deformation plays an important role in the fabric evolution of the iron formation rocks. The transformation along {111} creates planes of weakness that facilitate fracturing. The fracturing plus the dissolution result in a reduction of magnetite grain size, and the oriented precipitation results in layers of hematite platelets. These processes produce a new fabric characterized by a penetrative foliation and lineation.     

Natural Cadmium Isotopic Variations in Eight Geological Reference Materials (NIST SRM 2711, BCR 176, GSS-1, GXR-1, GXR-2, GSD-12, Nod-P-1, Nod-A-1) and Anthropogenic Samples, Measured by MC-ICP-MS

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.     

A Possible Role of Boiling in Ore Deposition: A Numerical Approach

Abstract. A possible role of boiling of the H₂O-NaCl-CO₂(-H₂S) fluid in ore deposition has been examined numerically by using the equations of state (EOS) of Duan et al. (1995, 1996), a modified EOS of Bowers and Helgeson (1983) and the water-rock interaction simulator MIX99 (Hoshino et al., 2000).
The following three models are examined to evaluate an efficiency of boiling on mineral precipitation: (1) hypothetical non-boiling process, (2) hypothetical boiling process with sulfur partitioned only in liquid phases and (3) boiling process in which partition ratios of H₂S between liquid and vapor phases are assumed to be the same as those of CO₂. The processes are simulated from 450C and 900 bar to 310C and 620 bar with an analytical step of 10C / 20 bar. Boiling occurs below 400C in the latter two processes when the initial composition (in mole fraction) of the fluid is: X_H2o = 0.84, X_NaC1 = 0.10 and X_Co2 = 0.06.
Ore deposition occurs abruptly at a boiling point when the partition ratios of total sulfur (X_s^vap/X_s^liq) are as high as those of total carbon during boiling. A decrease of concentration of sulfur in the liquid phase during boiling leads to an increase of pH of the solution, resulting in propelling mineral precipitation. It has been made clear that a possible role of boiling in ore formation mainly depends on the partition ratios of sulfur between the liquid and vapor phases, although they cannot be estimated accurately by the currently available EOS.     

Mechanism of chalcopyrite formation from iron monosulphides in aqueous solutions (< 100°C, pH 2–4.5)

In low-temperature aqueous solutions (< 100°C, pH 2–4.5), chalcopyrite (CuFeS₂) does not form through direct precipitation from solution. The pathway is exclusively via precursor iron sulphides and dissolved Cu salts. The reaction of dissolved Cu (II) salts with natural hexagonal pyrrhotite (Fe_0.9S) is diffusion controlled. The initial stage has an apparent activation energy of 11.4 ± 1.8 kJ mol⁻¹ and the rate (in units of mol dm⁻³s⁻¹ cm⁻²) is independent of the solid reactant surface area. The reaction proceeds through a series of metastable Cu-Fe-sulphide intermediaries. These phases form a series of ephemeral layers penetrating into the pyrrhotite surface. The first phase formed has the stoichiometry Cu_0.1Fe_0.9S. No Fe is released into the solution during its formation and this, together with the extremely low apparent activation energy and the stoichiometry, suggest that it is formed by stuffing of electron holes in the pyrrhotite structure with Cu ions. The transformation from the hexagonal close-packed arrangement of the pyrrhotite structure to the essentially cubic packing in chalcopyrite proceeds through a series of intermediaries, approximating in composition to members of the cubanite group. The rate of formation of these phases is controlled by the coupled diffusion of Fe (II), Fe (III), Cu (I) and Cu (II) species through the surface reaction zone, although the process as a whole can be approximated by steady-state diffusion of total Cu into a semi-infinite medium. Experiments with metastable precursor iron monosulphide phases, including amorphous FeS and synthetic mackinawite indicate similar reaction pathways.

The results suggest that chalcopyrite formation in low-temperature natural systems may be significantly constrained by kinetic factors. Chalcopyrite is, at least, a diagenetic mineral since its formation requires the prior formation of iron sulphides. However, at ambient temperatures its formation is probably limited to very early diagenesis.     

Refinements in BaSO4 to CO2 Preparation and δ18 O Calibration of the Sulfate Reference Materials NBS-127, IAEA SO-5 and IAEA SO-6

Refinements have been made to achieve over 99% yield in the conversion of CO to CO₂ in order to improve the reproducibility and accuracy of δ¹⁸ O measurements in sulfates. BaSO₄ (10-15 mg) was mixed with an identical amount of spectrographic-grade graphite and loaded into a Pt boat. The mixture was gradually heated to 1100 °C to reduce sulfate to CO and CO₂; the former gas was simultaneously converted to CO₂ by a glow discharge between Pt electrodes immersed in a magnetic field (produced by a pair of external neodymium magnets). A small memory effect was noticed during the analysis (less than 0.3‰ per 10‰ difference in δ¹⁸ O between two subsequently analysed samples). The memory effect, however, was suppressed by repetitive preparation of the same specimen. CO₂ produced in this way from sulfate reference samples was analysed on a dual inlet and triple collector mass spectrometer along with CO₂ equilibrated with VSMOW, GISP and SLAP water reference samples. To avoid large departures of measured isotope ratios from ¹⁸O/¹⁶O of the working calibrator we used CO₂ gas prepared from ocean water sulfate for this purpose. The calibrated δ¹⁸ O values (in ‰) obtained in this way for NBS-127, IAEA SO-5 and IAEA SO-6 reference materials were 8.73 ± 0.05, 12.20 ± 0.07 and -10.43 ± 0.12, respectively.     

High Sensitivity Analysis of Trace Element-Poor Geological Reference Glasses by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS)

Fifty-two trace elements in NIST SRM 614, 616 and MPI-DING BM90/21-G glass reference materials as well as in NIST SRM 612, USGS BCR2-G and other MPI-DING reference glasses (KL2-G, GOR132-G, GOR128-G, ATHO-G, Tl-G, StHs6/80-G and ML3B-G) were determined by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Accurate ultra-low trace element abundances in the NIST SRM 614, 616 and BM90/21-G reference glasses down to lower ng g⁻¹ levels were determined with relative standard deviations (RSD) of less than 10%. Limits of detection using He as carrier gas were up to two times lower than with Ar and were 0.004 to 0.12 μg g⁻¹ for elements of lower mass numbers (amu < 85) and 0.002 to 0.06 μg g⁻¹ for elements having amu < 85. The measured concentrations generally agree within 15% with previous studies except for B in NIST SRM 614 and 616, which appears to be heterogeneously distributed, and Co, Zn, Ga and Ag in NIST SRM 616 for which the existing data set is too small to evaluate the discrepancies. New values for As (0.593 μg g⁻¹), Ag (0.361 μg g⁻¹) and Cd (0.566 μg g⁻¹) in NIST SRM 614 and new values for Na (94864 μg g⁻¹) and As (0.276 μg g⁻¹) in NIST SRM 616 are reported.