Understanding the History of Rocks by the Use of Microbeam Analysis Techniques

 In order to understand the physical and chemical processes that occur in complex systems such as geological materials, one needs to look at the minerals involved on as fine a scale as possible; studying the mutual relationships among the different phases in terms of texture, chemical composition, zonation, etc., in the original petrographic context. This paper reports how the study of a rock through microanalysis can be done. The potentialities of the various microanalytical techniques such as electron microprobe analysis (EMPA), cathodoluminescence (CL), particle-induced X-ray emission (PIXE), secondary ion mass spectrometry (SIMS) and accelerator mass spectrometry (ASM) are presented. Each of them has its own characteristics and limits. And only through a multiple-technique approach it is possible to investigate the various components of the rock system and from this, unravel its history.     

Isotopic study of natural fission reactors at Oklo and Bangombé, Gabon

The Oklo and Bangombé uranium ores in the Republic of Gabon are fossils of natural fission reactors. Many elements in these natural fission reactors show isotopic anomalies derived from fission and neutron capture reactions. Isotopic analyses of uraninites and some other minerals provide useful information on the geochemical behavior of fission products and nuclear chemical characterization of the reactors. Integrated isotopic measurements by whole rock analysis with inductively coupled plasma mass spectrometry (ICP-MS) and thermal ionization mass spectrometry (TIMS) and by in-situ analysis with secondary ion mass spectrometry (SIMS) make it possible to clarify the migration processes of fissiogenic nuclides over a range of scales from micro meters to meters.     

Trace element analysis of geological glasses by laser plasma ionization mass spectrometry (LIMS): A comparison with other multielement and microanalytical methods

Laser plasma ionization mass spectrometry (LIMS) is used in our laboratory as an in-situ microanalytical method for the investigation of solids, especially of rocks and minerals. To demonstrate the accuracy of this method we have analyzed homogeneous geological glass samples. The results are compared with data obtained from other analytical techniques. The performance of the LIMS method for geochemical investigations is discussed. Received: 2 December 1996 / Revised: 21 February 1997 / Accepted: 26 February 1997     

Elemental fractionation in laser ablation inductively coupled plasma mass spectrometry

The major challenge to the use of laser ablation sample introduction, combined with inductively coupled plasma mass spectrometry, is the problem of calibration. In the geological analysis of minerals, calibration is complicated by the extraordinarily wide variety of sample matrices which may be encountered. While there is a lack of mineral standards with well characterized concentrations near 1 microg/g, the NIST glass reference materials (SRM 610-617) have been demonstrated to be very useful for the analysis of a wide variety of lithophile elements in silicate samples. An internal reference element, for which the concentration is known in the sample, has been widely used to make corrections for the multiplicative effects of volume (or weight) of the sample ablated, instrument drift, and matrix effects. This procedure works extremely well where elements being determined and the internal reference element being used share similar ablation behaviours; i.e., they do not fractionate progressively during the ablation and transport process. In this study, it is demonstrated that, in terms of ablation behaviour, elements fall into several distinct clusters and that the elements within these clusters correlate well with each other during a period of ablation. Thus, elements within a cluster can be determined using an internal reference element from within the same cluster. While a combination of periodic varying properties typifies the clusters, the geochemical classification of elements into lithophile (silicate loving), and chalcophile (sulphide loving) appears to offer the best characterization of the major groups.     

全二维气相色谱在石油地质样品分析中的应用进展

对石油地质样品的化学组成进行全面准确的剖析,可以获得丰富的地球化学信息,为油气勘探工作提供科学依据。然而,该类样品除了组成复杂之外,还易受到各种物理（如蒸发、乳化、扩散、溶解和吸附）、化学（如光降解）和生物（如微生物降解）过程的影响。这些特点给样品的分析研究工作带来了极大的困难,传统的一维气相色谱/质谱技术很难对其进行理想的分离。全二维气相色谱（GC×GC）作为新发展起来的一种分离技术,在复杂样品分析方面具有独特的优势,虽然在石油地质样品分析中的应用相对较晚,但也日益受到关注。本文主要综述了近5年来GC×GC在石油地质方面国内外的研究进展以及存在的主要问题,并对今后的研究进行了展望。     

Inorganic trace analysis by mass spectrometry

Mass spectrometric methods for the trace analysis of inorganic materials with their ability to provide a very sensitive multielemental analysis have been established for the determination of trace and ultratrace elements in high-purity materials (metals, semiconductors and insulators), in different technical samples (e.g. alloys, pure chemicals, ceramics, thin films, ion-implanted semiconductors), in environmental samples (waters, soils, biological and medical materials) and geological samples. Whereas such techniques as spark source mass spectrometry (SSMS), laser ionization mass spectrometry (LIMS), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), glow discharge mass spectrometry (GDMS), secondary ion mass spectrometry (SIMS) and inductively coupled plasma mass spectrometry (ICP-MS) have multielemental capability, other methods such as thermal ionization mass spectrometry (TIMS), accelerator mass spectrometry (AMS) and resonance ionization mass spectrometry (RIMS) have been used for sensitive mono- or oligoelemental ultratrace analysis (and precise determination of isotopic ratios) in solid samples. The limits of detection for chemical elements using these mass spectrometric techniques are in the low ng g⁻¹ concentration range. The quantification of the analytical results of mass spectrometric methods is sometimes difficult due to a lack of matrix-fitted multielement standard reference materials (SRMs) for many solid samples. Therefore, owing to the simple quantification procedure of the aqueous solution, inductively coupled plasma mass spectrometry (ICP-MS) is being increasingly used for the characterization of solid samples after sample dissolution. ICP-MS is often combined with special sample introduction equipment (e.g. flow injection, hydride generation, high performance liquid chromatography (HPLC) or electrothermal vaporization) or an off-line matrix separation and enrichment of trace impurities (especially for characterization of high-purity materials and environmental samples) is used in order to improve the detection limits of trace elements. Furthermore, the determination of chemical elements in the trace and ultratrace concentration range is often difficult and can be disturbed through mass interferences of analyte ions by molecular ions at the same nominal mass. By applying double-focusing sector field mass spectrometry at the required mass resolution—by the mass spectrometric separation of molecular ions from the analyte ions—it is often possible to overcome these interference problems. Commercial instrumental equipment, the capability (detection limits, accuracy, precision) and the analytical application fields of mass spectrometric methods for the determination of trace and ultratrace elements and for surface analysis are discussed.     

Determination of Rare Earth Elements in Garnet Minerals,Geological Materials by Inductively Coupled Plasma–Atomic Emission Spectral and Mass Spectral Analysis

Abstract

The performance of inductively coupled plasma–atomic emission spectrometry (ICP‐AES) for the determination of 14 lanthanides and Yttrium was evaluated by comparison with inductively coupled plasma–mass spectral (ICP‐MS) analysis. The geochemical reference samples (GRS), DNC‐1(diabase), AGV‐1(andesite), Sy‐2(syenite), MRG‐1(gabbro), AN‐G(anorthosite), AC‐E(granite), and MAG‐1(marine mud) were chosen as test materials and analyzed for checking the precision and reproducibility of the methods. The mineral garnet is separated from the black sands of the southwest coast of India, and the combined cation exchange–ICP method of AES analysis and MS analysis were carried out for the determination of rare earth elements. Both techniques are within the requirements needed for garnet minerals. The determination of rare‐earth elements in these minerals, which contain other elements as major contribution and trace distribution of rare‐earth elements, shows that ICP applied under the proper working condition lives up to the expectations. Major element analysis gives the formula of garnet of Manavalakurichi (MK) as (FeCaMg)_2.79Al_2.07Si_3.05O₁₂ approximated to Fe₃Al₂Si₃O₁₂, hence of almandine-type garnet. The enrichment of heavy lanthanides compared to the light lanthanides indicates that these lanthanides occupy the coordinaton site of Fe²⁺ by replacement. Both techniques are excellent in determining the very low concentration of lanthanides in geological materials, specifically garnet.     

Electrospray ionization enters the final frontier: Mass spectrometry's role in understanding electrospray thrusters and their plumes

Electrospray thrusters using ionic liquid (IL)‐based propellants are quickly gaining popularity in spacecraft design. Mass spectrometry is especially well‐suited to provide important knowledge on the fundamentals of how these systems work and on evaluating their efficiencies and impacts, given that the operating principles of electrospray thrusters closely mimics the mass spectrometry experiment – in both ions are generated by electrospray and then enter a vacuum. Here, electrospray thruster technology and IL‐based propellants are briefly introduced. This introduction is then followed by a discussion of mass spectrometry's current contribution to the study of IL‐based electrospray thrusters – with a focus on electrospray, dissociation, and spectroscopy studies – and a brief discussion of areas ripe for immediate contributions from the mass spectrometry community.     

Elemental fractionation in laser ablation inductively coupled plasma mass spectrometry

The major challenge to the use of laser ablation sample introduction, combined with inductively coupled plasma mass spectrometry, is the problem of calibration. In the geological analysis of minerals, calibration is complicated by the extraordinarily wide variety of sample matrices which may be encountered. While there is a lack of mineral standards with well characterized concentrations near 1 g/g, the NIST glass reference materials (SRM 610–617) have been demonstrated to be very useful for the analysis of a wide variety of lithophile elements in silicate samples. An internal reference element, for which the concentration is known in the sample, has been widely used to make corrections for the multiplicative effects of volume (or weight) of the sample ablated, instrument drift, and matrix effects. This procedure works extremely well where elements being determined and the internal reference element being used share similar ablation behaviours; i.e., they do not fractionate progressively during the ablation and transport process. In this study, it is demonstrated that, in terms of ablation behaviour, elements fall into several distinct clusters and that the elements within these clusters correlate well with each other during a period of ablation. Thus, elements within a cluster can be determined using an internal reference element from within the same cluster. While a combination of periodic varying properties typifies the clusters, the geochemical classification of elements into lithophile (silicate loving), and chalcophile (sulphide loving) appears to offer the best characterization of the major groups.     

An online method combining a thermal conversion elemental analyzer with isotope ratio mass spectrometry for the determination of hydrogen isotope composition and water concentration in geological samples

An online continuous-flow method, combining a thermal conversion elemental analyzer (TC/EA) with isotope ratio mass spectrometry (MS), is evaluated for the determination of both the hydrogen isotope composition and the water concentration of hydrous and nominally anhydrous minerals. The technique involves reduction of hydrous minerals or nominally anhydrous minerals by reaction with glassy carbon at 1450 degrees C in a helium stream. The product gases, H2 and CO, are separated on a gas chromatographic column prior to analysis in the mass spectrometer. Calibration curves for the H concentration analysis were generated from a standard of benzoic acid (C7H6O2) that has an H concentration of 5.0 wt%; the analytical uncertainties were better than +/-0.05% in our runs. Two standards of material with given D values, polyethylene IAEA-CH-7 and biotite NBS-30, were tested for the purpose of calibrating a natural garnet 04BXL02 representing nominally anhydrous minerals. Preheating at 90 degrees C for 12 h was found to be suitable for removing adsorption water on the sample surface. This results in constant D values and total H2O contents for the garnet, with weighted means of -94 +/- 1 and 522 +/- 11 ppm (wt), respectively. The TC/EA-MS technique allows routine analysis of sample sizes as small as 0.01 microL H2O. For natural minerals, absolute reproducibilities for D values are +/-0.5 to +/-2 (1) and relative uncertainties for total H2O concentrations are at levels of +/-1% to +/-3% (1). Therefore, this online method can be used for the quantitative determination of H isotope composition and H2O concentration of either hydrous or anhydrous minerals.     

Approaches to dioxin analysis by HRGC-HRMS and hybrid HRGC-MS-MS

A hybrid mass spectrometer with an EBQQ configuration was used to investigate two approaches to trace dioxin analysis: high resolution gas chromatography – high resolution mass spectrometry (HRGC-HRMS) and high resolution gas chromatography – mass spectrometry – mass spectrometry (HRGC-MS-MS). It is shown that selected ion monitoring (SIM) HRGC-HRMS exhibits better selectivity for dioxins separated on a cyanopropyl column than is otherwise obtained under medium resolution mass spectrometry (3,000 resolution), while optimization of conditions for HRGC-MS-MS allowed the observation of 350 femtograms of the highly toxic 2,3,7,8-TCDF at a S/N ratio of 5:1. Both methods were applied to environmental samples with good results.     

超细样品的地质分析应用

采用X-射线荧光(XRF)、电感耦合等离子体光谱和质谱(ICP-AES/MS)技术,研究了超细地质分析样品(约800目)的分析方法和条件.结果表明,对于超细样品,XRF可直接粉末压片制样而不必高温熔融制样进行高精度的主、次组分测定;ICP-AES/MS的取样量可降至2 ～5 mg(仅为-200目样品的1/20 ～1/50),试剂用量大大减小,样品更易消解,不仅可节约成本,降低能耗,还显著减小了对环境的影响.讨论了发展超细样品分析的意义及对地质分析技术发展的可能影响.     

Determination of platinum group elements and gold in geological materials: a review of recent magnetic sector and laser ablation applications

Inductively coupled plasma mass spectrometry (ICP-MS) has been used extensively as a rapid and accurate instrumental technique for determinations of platinum group elements (PGEs) and gold. Methods based upon ICP-MS have been important in analyses of many types of samples, and especially of geological materials containing very low concentrations of these elements. Recently, analytical methods based upon ICP-MS have been improved and widened in scope by the introduction of new magnetic sector (or high resolution) spectrometers, and laser ablation (LA) sampling. Detection limits attainable for PGEs and Au using magnetic sector instruments in analytical procedures cited here are as low as 0.01-0.02 pg g⁻¹; instruments have a dynamic range of up to nine orders of magnitude. This review describes applications of the techniques to analyses of PGEs and gold in minerals, nodules, meteorites, ice, sediments, airborne particulates and reference materials. The period covered is 1998-2002.     

Chemometric evaluation of time-of-flight secondary ion mass spectrometry data of minerals in the frame of future in situ analyses of cometary material by COSIMA onboard ROSETTA

Chemometric data evaluation methods for time-of-flight secondary ion mass spectrometry (TOF-SIMS) have been tested for the characterization and classification of minerals. Potential applications of these methods include the expected data from cometary material to be measured by the COSIMA instrument onboard the ESA mission ROSETTA in the year 2014. Samples of the minerals serpentine, enstatite, olivine, and talc have been used as proxies for minerals existing in extraterrestrial matter. High mass resolution TOF-SIMS data allow the selection of peaks from inorganic ions relevant for minerals. Multivariate cluster analysis of peak intensity data by principal components analysis and the new method CORICO showed a good separation of the mineral classes. Classification by k nearest-neighbor classification (KNN) or binary decision trees (CART method) results in more than 90% correct class assignments in a leave-one-out cross validation.     

Microanalysis of geological samples by laser plasma ionization mass spectrometry (LIMS)

Laser plasma ionization mass spectrometry (LIMS) has been applied for in-situ microanalysis of minerals and inclusions in geo- and cosmochemical samples down to the ng/g concentration level. A great advantage of this method is that at high laser power densities (2×10¹⁰ W/cm²) used, most elements are ionized with about the same efficiency independent of chemistry and mineralogy of the samples. A procedure has been developed which allows quantitative analysis of about 30 trace elements with an accuracy of better than 25%.     

Determination of stoichiometry and concentration of trace elements in thin BaxSr1–xTiO3 perovskite layers

This paper describes an analytical procedure for determining the stoichiometry of Ba_xSr_1–xTiO₃ perovskite layers using inductively coupled plasma mass spectrometry (ICP-MS). The analytical results of mass spectrometry measurements are compared to those of X-ray fluorescence analysis (XRF). The performance and the limits of solid-state mass spectrometry analytical methods for the surface analysis of thin Ba_xSr_1–xTiO₃ perovskite layers – sputtered neutral mass spectrometry (SNMS) – are investigated and discussed.     

Investigation of the ionization processes occurring in liquid-assisted secondary ion mass spectrometry of derivatized monosaccharides

Several derivatized monosaccharides, the 2-deoxy-D -ribofuranoses, have been studied by liquid-assisted secondary ion mass spectrometry (LSIMS) in order to gain insight into the factors affecting ionization in FAB/LSIMS. Examination of the mass spectra for these compounds obtained in eight liquid matrices (diethanolamine, ethylene glycol, glycerol, 2-hydroxyethyl disulfide, 2-hydroxyphenethyl alcohol, 3-nitrobenzyl alcohol, sulfolane and thioglycerol) reveals that in all cases the anomalous [M – H]⁺ ion is the predominant species in the molecular ion region and that [M + Na]⁺ species are observed in the presence of Na⁺. The analysis of these compounds by chemical ionization with ammonia shows [M + H]⁺ as the major species while [M – H]⁺ is essentially absent. This indicates that the ionization processes occurring in the two techniques are not analogous. Thermodynamic considerations based on the gas-phase hydride ion affinities of the protonated matrices do not support a predominant gas-phase mechanism for the formation of [M – H]⁺ in LSIMS. However, it is possible using solvation energies to rationalize the formation of [M – H]⁺ in terms of condensed-phase ionization processes which take place either in the liquid matrix or in the dense selvedge region immediately above the surface where extensive solvation is present. Electrospray data obtained for one of the derivatized monosaccharides indicates that the [M – H]⁺ is not performed in the condensed phase in LSIMS and that it is the product of fast ion beam-induced processes. While the nature of the matrix is seen to have little effect on the intensities of [M – H]⁺ and [M + H]⁺ it is observed to be an important factor for the intensity of M⁺˙ for one of the monosaccharides. This effect can be related to the electron-scavenging properties of the matrices and reinforces the hypothesis that condensed phase processes are significant in ionization.     

Phthalide metabolites produced by mangrove endophytic fungus Pestalotiopsis sp. SAS4

Two new phthalide derivatives ( 1 – 2 ) and four known phthalide compounds ( 3 – 6 ) were purified from the culture of a mangrove endophytic fungus Pestalotiopsis sp. SAS4. Their chemical structures were established by analyses of 1D and 2D nuclear magnetic resonance (NMR) and high resolution mass spectrometry (HR-MS) spectroscopic data. All of these compounds were evaluated in vitro for antibacterial, cytotoxicity, and resistance to hypoxic–ischemic injury activities.     

Preparation of single cells for imaging/profiling mass spectrometry

Characterizing chemical changes within individual cells is important for determining fundamental mechanisms of biological processes that will lead to new biological insights and improved disease understanding. Analyzing biological systems with imaging and profiling mass spectrometry (MS) has gained popularity in recent years as a method for creating chemical maps of biological samples. To obtain mass spectra that provide relevant molecular information about individual cells, samples must be prepared so that salts and other cell culture components are removed from the cell surface and that the cell contents are rendered accessible to the desorption beam. We have designed a cellular preparation protocol for imaging/profiling MS that removes the majority of the interfering species derived from the cellular growth medium, preserves the basic morphology of the cells, and allows chemical profiling of the diffusible elements of the cytosol. Using this method, we are able to reproducibly analyze cells from three diverse cell types: MCF7 human breast cancer cells, Madin-Darby canine kidney (MDCK) cells, and NIH/3T3 mouse fibroblasts. This preparation technique makes possible routine imaging/profiling MS analysis of individual cultured cells, allowing for understanding of molecular processes within individual cells.     

Ion/Neutral,Ion/Electron,Ion/Photon,and Ion/Ion Interactions in Tandem Mass Spectrometry: Do We Need Them All? Are They Enough?

A range of strategies and tools have been developed to facilitate the determination of primary structures of analyte molecules of interest via tandem mass spectrometry (MS/MS). The two main factors that determine the primary structural information present in an MS/MS spectrum are the type of ion generated from the analyte molecule and the dissociation method. The ion type subjected to dissociation is determined by the ionization method/conditions and ion transformation processes that might take place after initial gas-phase ion formation. Furthermore, the range of analyte-related ion types can be expanded via derivatization reactions prior to mass spectrometry. Dissociation methods include those that simply alter the population of internal states of the mass-selected ion (i.e., activation methods like collision-induced dissociation) as well as processes that rely on the transformation of the ion type prior to dissociation (e.g., electron capture dissociation). A variety of ion interactions have been studied for the purpose of ion dissociation and ion transformation, including ion/neutral, ion/photon, ion/electron, and ion/ion interactions. A wide range of phenomena have been observed, many of which have been explored/developed as means for structural analysis. The techniques arising from these phenomena are discussed within the context of the elements of structural determination in tandem mass spectrometry: ion-type definition and dissociation. Unique aspects of the various ion interactions are emphasized along with any barriers to widespread implementation.