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1.
An innovative approach of double pulse laser‐induced breakdown spectroscopy (DP‐LIBS) coupled with optical microscopy was applied to the characterisation and quantitative analysis of the Agoudal iron meteorite in bulk sample and in petrographic thin section. Qualitative analysis identified the elements Ca, Co, Fe, Ga, Li and Ni in the thin section and the whole meteorite. Two different methods, calibration‐free LIBS and one‐point calibration LIBS, were used as complementary methodologies for quantitative LIBS analysis. The elemental composition data obtained by LIBS were in good agreement with the compositional analyses obtained by traditional methods generally applied for the analysis of meteorites, such as ICP‐MS and EDS‐SEM. Besides the recognised advantages of LIBS over traditional techniques, including versatility, minimal destructivity, lack of waste production, low operating costs, rapidity of analysis, availability of transportable or portable systems, etc., additional advantages of this technique in the analysis of meteorites are precision and accuracy, sensitivity to low atomic number elements such as Li and the capacity to detect and quantify Co contents that cannot be obtained by EDS‐SEM.  相似文献   

2.
We present an open‐source algorithm in Mathematica application (Wolfram Research) with a transparent data reduction and Monte Carlo simulation of systematic and random uncertainties for U‐Th geochronometry by multi‐collector ICP‐MS. Uranium and thorium were quantitatively separated from matrix elements through a single U/TEVA extraction chromatography step. A rigorous calibrator‐sample bracketing routine was adopted using CRM‐112A and IRMM‐035 standard solutions, doped with an IRMM‐3636a 233U/236U ‘double‐spike’ to account for instrumental mass bias and deviations of measured isotope ratios from certified values. The mean of 234U/238U and 230Th/232Th in the standard solutions varied within 0.42 and 0.25‰ (permil) of certified ratios, respectively, and were consistent with literature values within uncertainties. Based on multiple dissolutions with lithium metaborate flux fusion, U and Th concentrations in USGS BCR‐2 CRM were updated to 1739 ± 2 and 5987 ± 50 ng g?1 (95% CI), respectively. The measurement reproducibility of our analytical technique was evaluated by analysing six aliquots of an in‐house reference material, prepared by homogenising a piece of speleothem (CC3A) from Cathedral Cave, Utah, which returned a mean age of 21483 ± 63 years (95% CI, 2.9‰). Replicate analysis of ten samples from CC3A was consistent with ages previously measured at the University of Minnesota by single‐collector ICP‐MS within uncertainties.  相似文献   

3.
研究了电感耦合等离子体发射光谱同时测定地质样品中次量钨、锡、钼的方法。为了避免基体干扰,采用氢氟酸低温分解试样,蒸干除硅,硅以四氟化硅的形式挥发除去。为了减小盐分,用少量过氧化钠熔融未被分解完全的试样残渣,热水提取,盐酸酸化,电感耦合等离子体发射光谱法同时测定钨、锡、钼。方法相对标准偏差(RSD,n=12)为钨10.80%,锡6.67%,钼8.33%。标准曲线线性浓度上限为:三氧化钨30.0 mg/L,锡40.0 mg/L,钼40.0 mg/L。方法经国家一级标准物质验证,分析结果与标准值相符。  相似文献   

4.
We investigate the performance of sample preparation of gold ores using vibratory (bowl, ring and puck type) mills in common use in mineral analytical laboratories. The main criteria for effective grinding are using reduced grinding charge masses ≤ ca. 50% of nominal bowl capacity and using a grinding aid to prevent caking. We show that gold particles of millimetre scale can be comminuted to ≤ 100 µm by grinding in silica flour, bauxite, synthetic carborundum, or mixtures of silica and these materials using times of up to 5 min and that 95% < 50 µm is achievable with extended grinding. This suggests that modified grinding techniques can be used to make sample masses ≤ 5 g viable for routine determination of gold in geological samples. We also demonstrate homogenisation of a gold‐bearing copper sulfide mineral flotation concentrate alone and in mixtures with silica by extended grinding at reduced charge masses. To support this work, we develop a convenient new benchmark of gold ore sample preparation performance ‘G’, an apparent maximum gold particle size interpolated from replicate analytical variance in order to overcome the limitations of laborious sieve fraction analysis of gold particle size. We show useful agreement between G and sieve fraction analysis of gold particle size in samples and test the viability of G experimentally and by analysis of literature data.  相似文献   

5.
李大勇  朱志雄  李靖  王亮 《岩矿测试》2020,39(1):135-142
应用X射线荧光光谱半定量分析软件（SQX）分析未知样品时,SQX软件可对样品中的9F～92U元素进行半定量分析,而对H2O、C这些参数不能直接测定。对于烧失量和结晶水含量较高的铝土矿、CO2含量较高的碳酸盐矿物、硫碳含量较高的硫化物金属矿等样品,平衡归一化计算时,未测定参数对样品中的Al2O3、SiO2、CaO、MgO、Fe等主要元素分析结果影响较大,半定量分析数据的准确度较低。本文通过试验研究,提出了一种校正模式。该校正模式根据XRF半定量分析初步结果,选择性地对未知样品中的烧失量、结晶水、二氧化碳、硫等参数进行化学定量分析,将化学定量分析结果输入SQX,二次平衡归一计算得出新的半定量分析结果。实验结果表明,使用该校正模式分析铝土矿、碳酸盐矿物、硫化物金属矿中的多元素,平均准确度提高了2.6～4.5倍。本方法可快速、较为准确地测定铝土矿、碳酸盐矿物、硫化物金属矿等高烧失量矿物中的多元素。  相似文献   

6.
样品采用HCl-HF-HNO3-HClO4四酸溶矿、H2SO4-HF-HNO3三酸溶矿、KOH碱熔3种分解方法进行处理,电感耦合等离子体发射光谱法(ICP-AES)测定钒钛磁铁矿中的铁、钛、钒。结果表明,3种样品处理方法应用于ICP-AES测定是可行的。KOH碱熔适用于方法比对,三酸溶矿适用于样品内检分析,四酸溶矿适用于大批量样品测定。对铁、钛、钒三元素选择适合的分析谱线,以冶金行业钒钛磁铁矿标准样品制备的溶液绘制标准曲线,可消除试液基体和介质不一致对测定结果的影响。样品试液中主要共存离子对选择的分析线干扰小。采用四酸溶矿ICP-AES测定铁、钛、钒的方法检出限分别为0.0032%、0.0024%、0.0003%,方法精密度(RSD,n=12)为0.43%～5.06%。经实验室间比对和批量样品方法比对实验,测定值无明显系统偏差。建立的方法具有样品分解完全、测定含量范围宽、分析简便快速、结果准确等优点,适用于钒钛磁铁矿样品中铁、钛、钒的测定。  相似文献   

7.
A voltammetric method for the determination of the high field‐strength elements Ti, Zr, Hf, Nb and Ta by adsorptive stripping of their tartrate complexes is presented. The applicability of the method to geological and metallurgical samples is illustrated by the analysis of certified reference materials (USGS BCR‐2 basalt, BCS‐CRM 388 zircon and Euronorm CRM 579‐1 ferroniobium). Suitable sample preparation techniques, involving fusion with LiBO2 and acidic and basic fluxes, followed by preliminary separation by anion chromatography are described. The method is rapid, affordable and environmentally friendly as it does not require problematic compounds such as hydrofluoric acid or toxic solvents and represents an alternative to more commonly used methods (AAS, ICP‐OES, ICP‐MS).  相似文献   

8.
玻璃熔片制样X射线荧光光谱法测定矾土中主次量组分   总被引：1，自引：1，他引：0  
薛秋红  李静  丁玉龙  马青 《岩矿测试》2010,29(2):182-184
建立了玻璃熔片-X射线荧光光谱测定进出口矾土中主、次量组分的分析方法,用可变α系数校正元素基体效应,同时进行谱线重叠校正。利用高纯化学试剂配制合成标准参考物质,球磨机混匀,熔融玻璃片法制备系列校准样片,用X射线荧光光谱法对样品中的二氧化硅、三氧化二铁、三氧化二铝、氧化钙、氧化镁、氧化钾、五氧化二磷、二氧化钛进行测定。方法回收率为98.1%~111.0%,经国家铝矾土标准物质GBW 07178、GBW 07179验证,结果与标准值基本一致。建立的方法解决了测试过程中标准样品种类和数量不足的难题。  相似文献   

9.
This study is Part II of a series that documents the development of a suite of calibration reference materials for in situ SIMS analysis of stable isotope ratios in Ca‐Mg‐Fe carbonates. Part I explored the effects of Fe2+ substitution on SIMS δ18O bias measured from the dolomite–ankerite solid solution series [CaMg(CO3)2–CaFe(CO3)2], whereas this complementary work explores the compositional dependence of SIMS δ13C bias (calibrated range: Fe# = 0.004–0.789, where Fe# = molar Fe/(Mg+Fe)). Under routine operating conditions for carbonate δ13C analysis at WiscSIMS (CAMECA IMS 1280), the magnitude of instrumental bias increased exponentially by 2.5–5.5‰ (session‐specific) with increasing Fe‐content in the dolomite structure, but appeared insensitive to minor Mn substitution [< 2.6 mole % Mn/(Ca+Mg+Fe+Mn)]. The compositional dependence of bias (i.e., the matrix effect) was expressed using the Hill equation, yielding calibration residual values ≤ 0.3‰ relative to CRM NBS‐19 for eleven carbonate reference materials (6‐μm‐diameter spot size measurements). Based on the spot‐to‐spot repeatability of a drift monitor material that ‘bracketed’ each set of ten sample‐spot analyses, the analytical precision was ± 0.6–1.2‰ (2s, standard deviations). The analytical uncertainty for individual sample analyses was approximated by combining the precision and calibration residual values (propagated in quadrature), suggesting an uncertainty of ± 1.0–1.5‰ (2s).  相似文献   

10.
To enable quality control of measurement procedures for determinations of Mg isotope amount ratios, expressed as δ26Mg and δ25Mg values, in Earth‐surface studies, the δ26Mg and δ25Mg values of eight reference materials (RMs) were determined by interlaboratory comparison between five laboratories and considering published data, if available. These matrix RMs, including river water SLRS‐5, spring water NIST SRM 1640a, Dead Sea brine DSW‐1, dolomites JDo‐1 and BCS‐CRM 512, limestone BCS‐CRM 513, soil NIST SRM 2709a and vegetation NIST SRM 1515, are representative of a wide range of Earth‐surface materials from low‐temperature environments. The interlaboratory variability, 2s (twice the standard deviation), of all eight RMs ranges from 0.05 to 0.17‰ in δ26Mg. Thus, it is suggested that all these materials are suitable for validation of δ26Mg and δ25Mg determinations in Earth‐surface geochemical studies.  相似文献   

11.
能量色散X射线荧光光谱法测定钼矿石中钼铅铁铜   总被引：1，自引：1，他引：0  
田文辉  王中岐  张敏 《岩矿测试》2008,27(3):235-236
建立了能量色散X射线荧光光谱法测定钼矿石中钼、铅、铁、铜的方法,讨论了粒度效应、矿物效应的影响因素,确定了采取粉末样品,用系列标准样品建立工作曲线,通过元素间相互校正消除基体效应,用内控标准样品考察了方法的精密度(RSD,n=11)为0.44%～15.4%。实际样品的测定结果和化学法相符,可满足日常分析工作需要。  相似文献   

12.
  相似文献   

13.
We document the development of a suite of carbonate mineral reference materials for calibrating SIMS determinations of δ18O in samples with compositions along the dolomite–ankerite solid solution series [CaMg(CO3)2–CaFe(CO3)2]. Under routine operating conditions for the analysis of carbonates for δ18O with a CAMECA IMS 1280 instrument (at WiscSIMS, University of Wisconsin‐Madison), the magnitude of instrumental bias along the dolomite–ankerite series decreased exponentially by ~ 10‰ with increasing Fe content in the dolomite structure, but appeared insensitive to minor Mn substitution [< 2.6 mol% Mn/(Ca+Mg+Fe+Mn)]. The compositional dependence of bias (i.e., the sample matrix effect) was calibrated using the Hill equation, which relates bias to the Fe# of dolomite–ankerite [i.e., molar Fe/(Mg+Fe)] for thirteen reference materials (Fe# = 0.004–0.789); for calibrations employing either 10 or 3 μm diameter spot size measurements, this yielded residual values ≤ 0.3–0.4‰ relative to CRM NBS 19 for most reference materials in the suite. Analytical precision was ± 0.3‰ (2s, standard deviations) for 10‐μm spots and ± 0.7‰ (2s) for 3‐μm spots, based on the spot‐to‐spot repeatability of a drift monitor material that ‘bracketed’ each set of ten sample‐spot analyses. Analytical uncertainty for individual sample analyses was approximated by a combination of precision and calibration residual values (propagated in quadrature), suggesting an uncertainty of ± 0.5‰ (2s) for 10‐μm spots and ± 1‰ (2s) for 3‐μm spots.  相似文献   

14.
《Applied Geochemistry》2006,21(5):730-747
Laser induced breakdown spectroscopy (LIBS) is a simple spark spectrochemical sensor technology in which a laser beam is directed at a sample surface to create a high-temperature microplasma and a detector used to collect the spectrum of light emission and record its intensity at specific wavelengths. LIBS is an emerging chemical sensor technology undergoing rapid advancement in instrumentation capability and in areas of application. Attributes of a LIBS sensor system include: (i) small size and weight; (ii) technologically mature, inherently rugged, and affordable components; (iii) real-time response; (iv) in situ analysis with no sample preparation required; (v) a high sensitivity to low atomic weight elements which are difficult to determine by other field-portable sensor techniques, and (vi) point sensing or standoff detection. Recent developments in broadband LIBS provide the capability for detection at very high resolution (0.1 nm) of all elements in any unknown target material because all chemical elements emit in the 200–980 nm spectral region. This progress portends a unique potential for the development of a rugged and reliable field-portable chemical sensor that has the potential to be utilized in variety of geochemical, mineralogical, and environmental applications.  相似文献   

15.
One requirement for isotope ratio measurement results with small measurement uncertainties is that the element of interest is effectively separated from the sample matrix. Efficient chemical separation of W from matrix components, especially Ti, can be challenging, particularly for large test portion masses (> 1 g). We present a new W separation procedure that takes advantage of the distinct complexation behaviour of Ti and W with citrate ligand in a moderately low pH, oxidising solution. This preparation procedure can reduce the Ti/W ratio of large (4–10 g) basaltic (i.e., high‐matrix) test portions by a factor of 105, relative to their original compositions, in a two‐step separation procedure. The procedure additionally provides a separate, well‐purified Mo fraction. We show that optimal separation requires precise selection of reagent concentrations and sample load. The procedure was employed to determine the μ182W composition of BHVO‐2 as ?6.7 ± 4.2 (2 standard deviation, 2s). The principles derived from this method may prove useful for chemical separation of other elements used for geochemical and cosmochemical applications given an appropriate selection of organic acid. Future successful applications of this method may reveal that the use of organic acids as procedural reagents is a currently under‐utilised tool for efficient chemical separation protocols.  相似文献   

16.
电气石是一类含硼的铝硅酸盐矿物,化学成分复杂、化学稳定性强,不易湿法分解,B_2O_3含量较高,导致其主次量元素的同时测定存在一定困难。本文采用熔融法制样,建立了X射线荧光光谱法测定电气石Na_2O、MgO、Al_2O_3、SiO_2、P_2O_5、K_2O、CaO、TiO_2、V_2O_5、Cr_2O_3、MnO、TFe_2O_3等主次量元素的分析方法。样品与四硼酸锂-偏硼酸锂-氟化锂(质量比为4.5∶1∶0.4)混合熔剂的稀释比例为1∶10,消除了粒度效应和矿物效应;在缺少电气石标准物质的情况下,选择土壤、水系沉积物及多种类型的地质标准物质绘制校准曲线,利用含量与电气石类似的标准物质验证准确度,测定结果的相对标准偏差小于4.2%。采用所建方法测定四种不同类型电气石实际样品,测定值与经典化学法基本吻合。本方法解决了电气石不易湿法分解和硼的干扰问题,测定结果准确可靠,与其他方法相比操作简便,分析周期短。  相似文献   

17.
Major and trace element compositions of fifteen silicate rock reference materials have been determined by a combined XRF and laser ablation ICP‐MS (LA‐ICP‐MS) technique on glasses prepared by fusing the sample with a lithium borate flux (sample:flux = 1:3). Advantages of this technique include the ability to measure major and trace element abundances on a single sample using a quick and simple preparation that attacks resistant phases such as zircon without the need for acid dissolution. The method is suitable for a wide variety of bulk compositions including mafic, intermediate and silicic rocks. Abundance‐normalized mass response patterns (the ratio of signal intensity to element concentration) of the LA‐ICP‐MS analyses vary systematically with major element composition, demonstrating the presence of a matrix effect that cannot be compensated by normalisation to a single internal standard element. Increasing the sampling distance between the ICP‐MS cone and the torch reduces the magnitude of this effect, suggesting that a mechanism related to residence time of ablated particles in the plasma may be at least partially responsible for the observed variations in mass response patterns. When using a matrix‐matched calibration, agreement of the LA‐ICP‐MS results with published reference values or those obtained by solution ICP‐MS is 10% relative. Analytical precision based on replicate analyses is typically 5% RSD. Procedural detection limits that include contributions from gas background and flux are 0.01‐0.1 μg g‐1 for the heavy mass trace elements (Rb‐U). Major element analyses by XRF show excellent agreement with results obtained using a conventional heavy element absorbing flux. High quality major and trace element data for silicate rocks can be achieved by a combined XRF and LA‐ICP‐MS analysis of Li2B4O7/LiBO2 fused glasses provided an appropriate matrix‐matched calibration is adopted.  相似文献   

18.
Isotope ratios of heavy elements vary on the 1/10000 level in high temperature materials, providing a fingerprint of the processes behind their origin. Ensuring that the measured isotope ratio is precise and accurate depends on employing an efficient chemical purification technique and optimised analytical protocols. Exploiting the disparate speciation of Cu, Fe and Zn in HCl and HNO3, an anion exchange chromatography procedure using AG1‐×8 (200–400 mesh) and 0.4 × 7 cm Teflon columns was developed to separate them from each other and matrix elements in felsic rocks, basalts, peridotites and meteorites. It required only one pass through the resin to produce a quantitative and pure isolate, minimising preparation time, reagent consumption and total analytical blanks. A ThermoFinnigan Neptune Plus MC‐ICP‐MS with calibrator‐sample bracketing and an external element spike was used to correct for mass bias. Nickel was the external element in Cu and Fe measurements, while Cu corrected Zn isotopes. These corrections were made assuming that the mass bias for the spike and analyte element was identical, and it is shown that this did not introduce any artificial bias. Measurement reproducibilities were ± 0.03‰, ± 0.04‰ and ± 0.06‰ (2s) for δ57Fe, δ65Cu and δ66Zn, respectively.  相似文献   

19.
贵州新民铝土矿矿床Li的地球化学特征与富集机制探究   总被引：2，自引：2，他引：0  
龙珍  付勇  何伟  唐波  龙克树  刘阳  王天顺 《矿床地质》2021,40(4):873-889
新民铝土矿床位于黔北务川-正安-道真地区(简称务正道地区)大塘向斜东翼,铝土矿(岩)型Li资源丰富.含矿岩系大竹园组(P1d)不同岩性的w(Li)有差别:土状-半土状铝土矿平均w(Li)为16.34×10-6,致密块状铝土矿平均w(Li)是803.84×10-6,铝土岩平均w(Li)是1436.22×10-6,黏土岩的平均w(Li)是786.62×10-6,梁山组泥岩的平均w(Li)是51.82×10-,韩家店群泥岩(页岩)的平均w(Li)是48.52×10-6,黄龙组灰岩的平均w(Li)是 11.99×10-6.由此可知,研究区铝土矿(岩)型Li资源主要富集在含矿岩系中上部的致密块状铝土矿、铝土岩和黏土岩中,顶板、底板以及土状-半土状铝土矿w(Li)较低.Li主要赋存于高岭石中,伊利石(水云母)和残存的三水铝石、勃姆石也可富集少量Li,当样品中赋锂矿物(高岭石、伊利石(水云母)、三水铝石和勃姆石)都存在时,高w(Li),主量元素w(Al3O2)、w(SiO2)、w(MgO)、w(K2O)、w(TiO2)和w(TFe2O3)与w(Li)的相关性也证实了上述结果.研究区的地球化学比值 CIA、w(Sr)/w(Cu)、u(CaO)/w(MgO)、w(Sr)/w(Ba)、w(V)/w(V+Ni)和 w(La)/w(Y)综合显示,炎热潮湿的古气候下,有机质腐烂形成酸性环境,半封闭海湾环境下,黏土化阶段中等强烈的化学风化程度和适宜的风化暴露剥蚀时间利于铝硅酸盐矿物和硅酸盐矿物化学键断裂,富集Al3+形成高岭石;风化程度过于强烈和长时间的风化剥蚀,继续脱Si富Al形成以硬水铝石为主的铝土矿;弱酸性-弱碱性以及氧化-还原过渡条件下,使得高岭石能最大程度的吸附Li元素.  相似文献   

20.
The low‐Sr content (generally < 100 μg g?1) in clinopyroxene from peridotite makes accurate Sr isotopic determination by LA‐MC‐ICP‐MS a challenge. The effects of adding N2 to the sample gas and using a guard electrode (GE) on instrumental sensitivity for Sr isotopic determination by LA‐MC‐ICP‐MS were investigated. Results revealed no significant sensitivity enhancement of Sr by adding N2 to the ICP. Although using a GE led to a two‐fold sensitivity enhancement, it significantly increased the yield of polyatomic ion interferences of Ca‐related ions and TiAr+ on Sr isotopes. Applying the method established in this work, 87Sr/86Sr ratios (Rb/Sr < 0.14) of natural clinopyroxene from mantle and silicate glasses were accurately measured with similar measurement repeatability (0.0009–0.00006, 2SE) to previous studies but using a smaller spot size of 120 μm and low‐to‐moderate Sr content (30–518 μg g?1). The measurement reproducibility was 0.0004 (2s, n = 33) for a sample with 100 μg g?1 Sr. Destruction of the crystal structure by sample fusion showed no effect on Sr isotopic determination. Synthesised glasses with major element compositions similar to natural clinopyroxene have the potential to be adopted as reference materials for Sr isotopic determination by LA‐MC‐ICP‐MS.  相似文献   

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