Detection of trace radioisotopes in soil,sediment and vegetation by glow discharge mass spectrometry

The possibility for the determination of some radioisotopes of cesium, strontium, plutonium, uranium and thorium by glow discharge mass spectrometry (GDMS) in soils, sediments and vegetations is investigated. The preparation of samples is described as a combination of the use of a conductive host matrix and a secondary cathode in order to decrease the dilution effect of the blending material for the trace level determination and to gain a stable discharge. Effects of interferences arising from the nature of the conductive host matrix and of the secondary cathode on the sensitivity of the method are discussed. The determination of (137)Cs and (90)Sr has been attempted and the results obtained were in agreement with those from other analytical techniques. Accuracy, internal and external precisions have been also evaluated. GDMS is shown to be a helpful technique for the determination of radioisotopes in environmental samples. Radioisotopes can be determined according to the matrix of the sample (e.g. grass), also in presence of isobaric interferences. However, limitations still exist on the application of GDMS.     

Isotopic abundance measurements on solid nuclear-type samples by glow discharge mass spectrometry

A double-focusing Glow Discharge Mass Spectrometer (GDMS) installed in a glovebox for nuclear sample screening has been employed for isotopic measurements. Isotopic compositions of zirconium, silicon, lithium, boron, uranium and plutonium which are elements of nuclear concern have been determined. Interferences arising from the matrix sample and the discharge gas (Ar) for each of these elements are discussed. The GDMS results are compared with those from Thermal Ionization Mass Spectrometry (TIMS). For boron and lithium at g/g-ng/g levels, the two methods gave results in good agreement. In samples containing uranium the isotopic composition obtained by GDMS was in agreement with those from TIMS independently of the enrichment. Attempts for the determination of plutonium isotopic composition were also made. In this case, due to the interferences of uranium at mass 238 and americium at mass 241, the GDMS raw data are complementary with those values obtained from physical non-destructive techniques.     

辉光放电质谱法测定高纯材料中痕量硫杂质

准确测定并控制材料中杂质元素含量是发挥高纯材料性能不可或缺的环节。辉光放电质谱法(GDMS)是准确、快速、高灵敏分析高纯材料中痕量及超痕量硫的理想方法。对GDMS分析高纯铜和镍基高温合金中痕量硫的质谱干扰进行了讨论,优化了放电电流和放电电压,采用多种标准物质对硫的相对灵敏度因子(RSF)进行了校准和验证,并与二次离子质谱法(SIMS)进行分析结果比对,验证了GDMS定量分析结果的准确性和可靠性。     

Isotopic abundance measurements on solid nuclear-type samples by glow discharge mass spectrometry

A double-focusing Glow Discharge Mass Spectrometer (GDMS) installed in a glovebox for nuclear sample screening has been employed for isotopic measurements. Isotopic compositions of zirconium, silicon, lithium, boron, uranium and plutonium which are elements of nuclear concern have been determined. Interferences arising from the matrix sample and the discharge gas (Ar) for each of these elements are discussed. The GDMS results are compared with those from Thermal Ionization Mass Spectrometry (TIMS). For boron and lithium at microg/g-ng/g levels, the two methods gave results in good agreement. In samples containing uranium the isotopic composition obtained by GDMS was in agreement with those from TIMS independently of the enrichment. Attempts for the determination of plutonium isotopic composition were also made. In this case, due to the interferences of uranium at mass 238 and americium at mass 241, the GDMS raw data are complementary with those values obtained from physical non-destructive techniques.     

Comparison between the use of direct current glow discharge mass spectrometry and inductively coupled plasma quadrupole mass spectrometry for the analysis of trace elements in nuclear samples

The quantitative determination of trace elements in nuclear samples by GDMS and ICP-MS is presented and compared. Spectral interferences, matrix effects, detection limits, precision and accuracy are discussed. Results for selected samples demonstrated that both techniques are complementary. The use of a multi-standard solution provides the most accurate results in ICP-MS, whereas in GDMS this is achieved by relative sensitivity factors (RSF) matrix matched. Nevertheless, the use of standard RSF allows a fast screening.     

Comparison between the use of direct current glow discharge mass spectrometry and inductively coupled plasma quadrupole mass spectrometry for the analysis of trace elements in nuclear samples

The quantitative determination of trace elements in nuclear samples by GDMS and ICP-MS is presented and compared. Spectral interferences, matrix effects, detection limits, precision and accuracy are discussed. Results for selected samples demonstrated that both techniques are complementary. The use of a multi-standard solution provides the most accurate results in ICP-MS, whereas in GDMS this is achieved by relative sensitivity factors (RSF) matrix matched. Nevertheless, the use of standard RSF allows a fast screening.     

辉光放电质谱法在无机非金属材料分析中的应用

辉光放电质谱法(GDMS)作为一种固体样品直接分析技术,已广泛应用于金属、半导体等材料的痕量和超痕量杂质分析。近年来,随着制样方法和离子源装置的改进,GDMS同样也能很好地应用于玻璃、陶瓷、氧化物粉末等非导体材料的成分分析。简介了GDMS的基本原理和分析特点,概述了GDMS在无机非金属材料分析的方法以及应用情况。     

Synthesis of spherical porous carbon by spray pyrolysis and its application in Li-S batteries

A spherical porous carbon (SPC) with high specific surface area is prepared by spray pyrolysis at 800 °C followed by removing silica template. The prepared SPC is employed as a conductive matrix in the sulfur cathode (S-SPC) for lithium–sulfur secondary batteries. The BET surface area of the prepared SPC sample is as high as 1,133 m² g^?1 and the total pore volume is 2.75 cm³ g^?1. The electrochemical evaluations including charge–discharge tests, cyclic voltammograms (CV), and electrochemical impedance spectrum suggest that the prepared S-SPC composite presents superior electrochemical stability when compared to the S-SP cathode. The as-prepared S-SPC composite shows improved cycle performance. The reversible discharge capacity is about 637 mAh g^?1 after 50 cycles, which is much better than that of the as-prepared sulfur–Super P carbon black composite. It may be attributed to the high porosity and excellent conductive structure of the SPC.     

Mass spectrometric isotopic and trace analysis of187Os

The application of mass spectrometric methods in the determination of isotopic abundance and of trace elements in highly enriched¹⁸⁷Os is described. The capability of ICP-MS in comparison with solid-state mass spectrometric techniques (SIMS, SNMS and GDMS) for the precise isotopic analysis of highly-enriched osmium has been investigated. The formation of cluster ions in several plasma types has been measured, and the problems of possible interferences from molecular and cluster ions is discussed.     

Porous carbon nanotubes improved sulfur composite cathode for lithium-sulfur battery

Porous multi-walled carbon nanotubes (PCNTs) with multiple mesopores structure are synthesized through activation of multi-walled carbon nanotubes (MWCNTs) by potassium hydroxide. The potassium hydroxide activation process results in a significantly enhanced specific surface area with numerous small pores. The as-obtained PCNTs are employed as the conductive matrix for sulfur in the sulfur cathode. Compared with the composite sulfur cathode based on the original MWCNTs, the sulfur-PCNTs cathode shows a significantly improved cycle performance and columbic efficiency. The reversible capacity is 530 mAh?g^?1 and columbic efficiency is 90 % after 100 cycles at a current density of 100 mA?g^?1. The improvement in the electrochemical performance for S-PCNT is mainly attributed to the enlarged surface area and the porous structure of the unique mesopores carbon nanotube host, which cannot only facilitate transport of electrons and Li⁺ ions, but also trap polysulfides, retard the shuttle effect during charge/discharge process.     

辉光放电质谱法测定高纯铟中痕量元素

采用辉光放电质谱法(GDMS)对高纯铟中铁、铜、铅、锌、铊、镉、锡等14种元素进行了测定,对仪器工作参数进行了优化,对预溅射过程时间的确定和质谱干扰的排除进行了讨论,结果表明,GDMS是目前具有足够灵敏度对高纯导电材料进行直接分析的有效手段。     

Glow discharge mass spectrometry — A versatile tool for elemental analysis

Summary Among recent MS techniques for elemental analysis, Glow Discharge Mass Spectrometry (GDMS) covers the field of direct analysis of conducting and semiconducting solids. In GDMS, a glow discharge in a working gas — usually Ar — at reduced pressure serves to atomize a solid sample by cathodic sputtering and to ionize the vapourized atoms. Ions are separated according to mass by a quadrupole filter (with low mass resolution) or a double focusing device (with high mass resolution). Use of a working gas implies the appearance of spectral interferences by molecular ions. Analysis may be impeded by these interferences, even in the case of high mass resolution. GDMS shows convincing analytical performance. Detection limits in the low ng/g region and even below can easily be realized. Precision is normally in the low percentage region, and a dynamic region of about nine orders of magnitude may be covered. Matrix effects are of no significant influence, and elemental sensitivities are within one order of magnitude. Semiquantitative analysis without standards is possible with limited accuracy, which is of considerable practical interest in the sub-microtrace region. Application experiences have mainly been gathered in analysis of very pure materials and semiconductors. GDMS has also been applied successfully for analytical characterization of technical surface layers.     

An innovative sample preparation procedure for trace and ultra-trace analysis on non-conducting powders by direct current glow discharge mass spectrometry

A novel preparation procedure has been developed in order to obtain stable, pin-shaped samples for the elemental analysis of non-conducting powders by direct current glow discharge mass spectrometry (dc GDMS): up to now, this technique has been mainly used for the characterization of metals and semiconductors. This work deals with a particular analytical application of the infiltration process, which is frequently employed for producing metal-matrix composites (MMC) for structural applications. The preparation procedure has been tested on germanium dioxide GeO₂, an inorganic compound available as high-purity powder. However, the method is, in principle, of general applicability: considering the quality of the results obtained so far, it might be particularly suitable for the detection of traces in powdered, non-conducting materials such as ceramics, bio-inorganics, soils, sediments and for the quantitation of major and minor elements in cases where limited amounts of samples are available (e.g. archaeological findings). The reproducibility of the preparation process is satisfactory: repeated observations by reflected light microscopy (RLM) prove that the oxide grains are homogeneously distributed within a well bounded region of the metallic host matrix. The use of composite pin-shaped samples leads to a rapid stabilization of the plasma discharge, with the consequence that the analytical results are generally superior to those obtained on similar samples prepared by more conventional procedures. In particular, from the ratio of the signals due to Ge⁺ and GeO⁺, it can be seen that a large predominance of the former species is quickly established in the plasma, with a correspondingly fast achievement of high detection sensitivities.     

Application of argon as the internal standard method in glow discharge mass spectrometry

Using (78)Ar(2)(+) as the internal standard (argon internal standard) in glow discharge mass spectrometry (GDMS) was investigated in detail. After comparing ion intensities and interferences, i.e. of argon ions, bi-atom argon ions and tri-atom argon ions, the (78)Ar(2)(+) was selected as the internal standard in the analysis. Mass spectral behavior of the argon internal standard affected by glow discharge current and voltage were studied. The ion intensity relationship between the argon internal standard and the matrix internal standard showed that the argon internal standard and the matrix internal standard have the same corrective effect on sample analysis. The experiment proved that the effects of the difference in analysis samples and the fluctuation of discharge conditions for analytical results were efficiently reduced if the argon internal standard was used. Moreover, the argon internal standard is similar to the matrix internal standard in correcting analytical results and both give satisfactory results. Elemental content in samples can be accurately determined by using the argon internal standard when the matrix content is unknown with good results.     

Synthesis and electrochemical properties of polypyrrole-coated poly(2,5-dimercapto-1,3,4-thiadiazole)

A new composite cathode active material, conductive polypyrrole (PPy)-coated poly(2,5-dimercapto-1,3,4-thiadiazole) (PDMcT) was prepared as a thin film via the surfactant template (TFST) technique. The formation of the uniform and well-connected film on the surface of PDMcT particles was confirmed by Fourier transform infrared spectra (FT-IR) and transmission electron micrographs (TEM). By cyclic voltammetry and galvanostatic charge–discharge tests, the coated composite showed a better electrochemical performance than PDMcT, such as enhanced redox processes and improved coulumbic efficiency, etc. The electrical conductivity of the material reached to 10⁻³ S cm⁻¹ and an initial discharge capacity of 250 mAhg⁻¹ was obtained. Moreover, it showed a slower fading of discharge capacity than PDMcT when used as cathode material in secondary lithium batteries with liquid electrolyte solution.     

Amplification of noble gas ion lines in the afterglow of a pulsed hollow cathode discharge and possible benefit for analytical glow discharge mass spectrometry

A high-current pulsed hollow cathode discharge was used to study the role of atomic and ionic metastables involved in ionization plasma processes. We observed the enhancement of the spectral emission lines of noble gas ions in the afterglow. A study of the processes that involve atomic and ionic metastables is of great interest since it should lead to a better understanding of and enhanced control over the ionization mechanisms crucial to analytical glow discharge mass spectrometry (GDMS) analysis. Figure Time profile of Ti, Ti⁺, and Ne⁺ spectral lines     

Fluorine Determination in a Hollow Cathode Discharge by Monofluoride Emission Spectra

Abstract

The applicability of the SiF and InF bands to determination of fluorine in a hollow cathode discharge has been studied. The InF bands have been used for the F determination in solid samples containing from 1% to 1x10^?4% F, and in solutions for the F^? concentration between 10 and 1000 mg 1^?1. The lowest detected amount of fluorine in solid sample was 10 ng (1x10^?5%).     

Accelerator mass spectrometry of actinides

Summary Accelerator mass spectrometry (AMS) is a sensitive and robust technique typically applied to the quantification of long-lived radioisotopes in samples too small to be decay-counted. AMS is characterized by a high rejection of interferences and a low susceptibility to matrix components, which reduce the demands on sample preparation chemistry. At Lawrence Livermore National Laboratory (LLNL), Center for Accelerator Mass Spectrometry (CAMS), we have developed an AMS capability for the measurement of actinide concentrations and isotopic ratios. To date, this capability has been primarily devoted to the measurement of ²³⁹Pu and ²⁴⁰Pu in bioassay and environmental samples including soils, sediments, waters, and human urine. For these analyses, a known amount of ²⁴²Pu is added to the samples as a reference isotope for normalization. Measurements of standard and intercomparison samples have shown that quantification is accurate and precise from at least 10⁶ to 10¹¹ atoms/sample. Recently, the ratios of ²⁴⁰Pu, ²⁴¹Pu, ²⁴²Pu, and +Pu to intrinsic ²³⁹Pu have been successfully measured in soil samples from nuclear test sites. In addition, initial measurements of U and Np isotopes have yielded results consistent with the Pu measurements with respect to sensitivity, accuracy, precision, and linear range.     

Cathode material for sodium-ion batteries based on manganese hexacyanoferrate: the role of the binder component

Sodium manganese hexacyanoferrate (NaMnHCF) was synthesized by a hydrothermal method and investigated as a cathode material for sodium-ion batteries. The morphology and the structure of NaMnHCF were investigated by X-ray diffraction, scanning electron microscopy, and EDX analysis. New composition of NaMnHCF cathode material for sodium-ion batteries with eco-friendly water-based binder consisting of conducting polymer poly-3,4-ethylenedioxythiopene/polystyrene sulfonate (PEDOT:PSS) dispersion and carboxymethyl cellulose (СМС) was proposed. The electrochemical properties of NaMnHCF cathode material with conductive polymer binder were investigated by cyclic voltammetry and galvanostatic charge-discharge, and the results were compared with the performance of a conventional PVDF-bound material. It was shown that the initial discharge capacity of electrodes with conductive binder is 130 mAh g⁻¹, whereas the initial discharge capacity of PVDF-bound electrodes was 109 mAh g⁻¹ (both at current density 120 mA g⁻¹, values normalized by NaMnHCF mass). The material with conductive binder also has better rate capability; however, it is losing in cycling capability to the electrode composition with conventional PVDF binder.

     

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.