GD-MS法和ICP-MS法测定高纯铌中痕量元素

采用辉光放电质谱法(GD-MS)对高纯铌中Ta,Mo,W等痕量杂质元素进行了测试,并对GD-MS工作参数进行了优化,部分元素与采用电感耦合等离子体质谱法(ICP-MS)定量分析的结果进行比较,对某些元素含量差别较大的原因进行了分析,论述了Element GD辉光放电质谱仪的特点及其在痕量杂质分析上的优势。     

辉光放电质谱法测定纯锡中24种杂质元素和锡记忆效应的消除

采用辉光放电质谱法(GDMS)测定了纯锡中24种杂质元素,分析方法为无标定量分析。分析前纯锡样品须依次用乙醇、水及乙醇冲洗以除去表面的灰尘颗粒,凉干后用于分析。本工作对辉光放电过程中的三项关键因素,即辉光放电电压、放电电流及放电气流三者在辉光放电溅射/电离时的相互关系及其对总离子流强度的影响进行了试验和讨论,并确定了仪器在最佳状态时辉光放电的优化条件为:放电电压590V,放电电流30mA,放电气流450mL·min~(-1)。为排除各元素测定中质谱(MS)干扰的影响,选择了在不同的分辨模式(中/高)下用相对丰度较高、干扰较少的质量数进行分析。所测定元素测定结果的相对标准偏差(n=5)均小于15%。各元素的检出限(3s)为0.003～0.174μg·g~(-1)之间。本方法所得测定结果与电感耦合等离子体原子发射光谱法(ICP-AES)或电感耦合等离子体质谱法(ICP-MS)的测定结果基本一致。经试验,通过更换GDMS的阳极帽、导流管、采样锥和透镜等4种耗材,可完全消除锡的记忆效应。     

高纯钛的辉光放电质谱法多元素分析

采用辉光放电质谱法(GD-MS)测定高纯钛中Mg、Al、Cr、Fe、V、Mn、Co、Ni、Cu、Zn、As、Sn、Sb、Ta、W、Pb、Bi等痕量杂质元素,并对GD-MS工作参数及条件进行了优化。主要元素与内标校正ICP-MS法定量分析的结果一致,对结果差异的原因进行分析,论述了Element GD辉光放电质谱仪在痕量杂质元素分析方面的优势。     

辉光放电质谱研究与应用新进展

简要介绍了辉光放电的基本原理,主要概述了过去４年有关辉光放电质谱研究的新进展,包括辉光放电质谱的基础研究,新装置和新方法的发展,以及辉光放电质谱的分析应用。文中最后展望了辉光放电质谱法的发展前景。     

直流辉光放电质谱法检测三氧化钼中痕量元素含量

建立了直流辉光放电质谱(dc-GDMS)测定三氧化钼中痕量元素含量的方法,优化了辉光放电参数,考察了三氧化钼制样面积对放电稳定性和灵敏度的影响。在优化条件下,测定2个三氧化钼标准样品BS ZZ42001和BS ZZ42003的相对灵敏度因子RSF₁和RSF₂,计算得到平均相对灵敏度因子RSF_A,对三氧化钼标准样品BS ZZ42002的测定结果进行校正,与BS ZZ42002的标准值比较,除Ti和Cd外,校正后得到的各元素测定值相对误差在±9.5%以内。对未知的三氧化钼样品测定结果进行校正,并与电感耦合等离子体原子发射光谱法(ICP-AES)和电感耦合等离子体质谱法(ICP-MS)结果对比。t检验结果表明,RSF_A校正值与ICP-AES/ICP-MS法测定值无显著性差异。该方法可为三氧化钼中多种痕量元素的快速定量分析提供参考。     

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。     

辉光放电质谱法测定钨钛合金中的微量杂质元素

采用辉光放电质谱法直接测定钨钛合金中的杂质元素。对放电电流、气体流量和预溅射时间等条件进行优化,用仪器内置的标准相对灵敏度因子(RSFstd)进行半定量分析。同时用已定值的钨钛合金作为标样校正仪器,获得校正后的相对灵敏度因子(RSFWTi),再应用于定量分析。结果表明,未校正测量值与参考值比值在0.5～1.6之间,相对标准偏差(RSDs)小于5%,满足半定量分析要求。经RSFWTi校正的测量值与电感耦合等离子体质谱法(ICP-MS)测得的结果比较,相对偏差(RD)小于20%,该方法适用于合金中杂质元素定量分析。     

辉光放电原子发射光谱法快速分析生铸铁

通过对辉光光源参数-放电电流、放电电压、预溅射时间和分析时间对生铸铁标样放电强度和稳定性影响的研究,优化光源参数,建立了辉光放电原子发射光谱法同时测定生铸铁中碳、硅、锰、磷、硫等12个元素的快速分析方法。分析生铸铁试样时发现了不同灰口铸铁在碳分析结果方面存在偏差,对碳的偏差进行了讨论并通过制样条件和光源参数的调整可以有效地减小偏差。通过对不同生铸铁样品进行准确度和精密度试验,结果表明:分析结果与标准值或化学法结果一致。分析一件试样的时间仅需2~5 min。     

晶体硅材料中杂质元素分析方法研究进展

综述了晶体硅材料中杂质元素含量测定的分析方法研究进展。晶体硅材料中杂质元素的分析方法主要包括红外吸收法、二次离子质谱法、中子活化分析法、辉光放电质谱法、电感耦合等离子体质谱法、X射线光谱分析及其它分析方法,引用文献41篇。     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Dominant reaction channels and the mechanism of silane decomposition in a H2-Si(s)-SiH4 glow discharge

Chemical relaxation mass spectrometry has been used to study the kinetics and mechanism in the silane-hydrogen-solid silicon system under conditions of glow discharge. The emphasis was on the main processes related to the deposition of amorphous and nanocrystalline silicon thin films. It is shown that under conditions of the deposition of a-Si and nc-Si the dominant reaction channel is the electron impact induced fragmentation of silane into molecular hydrogen and SiH₂ radical. The role of other processes, such as hydrogen abstraction, is discussed.     

A contribution to the study of matrix effects in the analysis of solid samples by D. C. glow discharge mass spectrometry

Relative Sensitivity Factors (RSF) for the analysis of 22 elements by glow discharge mass spectrometry have been determined from the multiple determination of 19 reference materials representing steels, Ni-based heat resisting alloys, copper, aluminium, molybdenum and indium by using an Ar/0.2 vol. % H₂ mixture as a filler gas. The measurements were made by using the VG 9000 glow discharge mass spectrometer. For all the materials analyzed, the relative variations of these factors were reduced by more than a factor of 2 when the Ar/H₂ mixture was substituted to the pure argon. In addition, the proposed technique greatly decreases the matrix effects, thus allowing the determination of the elemental composition of metallic samples without needing to use standard reference materials.     

On copper diffusion in silicon measured by glow discharge mass spectrometry

Copper contamination occurs frequently in silicon for photovoltaic applications due to its very fast diffusion coupled with a low solid solubility, especially at room temperature. The combination of these properties exerts a challenge on the direct analysis of Cu bulk concentration in Si by sputtering techniques like glow discharge mass spectrometry (GDMS). This work aims at addressing the challenges in quantitative analysis of fast diffusing elements in Si matrix by GDMS. N-type, monocrystalline (Czochralski) silicon samples were intentionally contaminated with Cu after solidification and consequently annealed at 900 °C to ensure a homogeneous distribution of Cu in the bulk. The samples were quenched after annealing to control the extent of the diffusion to the surface prior to the GDMS analyses, which were carried out at different time intervals from within few minutes after cooling onward. The Cu profiles were measured by high-resolution GDMS operating in a continuous direct current mode, where the integration step length was set to ～0.5 μm over a total sputtered depth of 8–30 μm. The temperature of the samples during the GDMS analyses was also measured in order to evaluate the diffusion. The Cu contamination of n-type Si samples was observed to be highly material dependent. The practical impact of Cu out-diffusion on the calculation of the relative sensitivity factor (RSF) of Cu in Si is discussed.     

直流辉光放电质谱法测定多晶硅中关键杂质元素的相对灵敏度因子

采用直流辉光放电质谱(dc-GD-MS)测定多晶硅中关键杂质元素的相对灵敏度因子(RSF).标样制作过程中主要是在连续通入氩气条件下将固定量的非标准多晶硅样品熔化,向硅熔体中均匀掺入浓度范围为1～30 μg/g的关键杂质元素(如B和P),采用快速固化法制成标样;再将制成的标准样品加工成一系列适合GD-MS扁平池(Flat Cell)的片状样品(20 mm×20 mm×2mm).采用二次离子质谱法(SI-MS)对标准样品中关键掺杂元素进行多次定量测定,取平均值作为关键杂质元素的精确含量.优化一系列质谱条件后,运用GD-MS对标样中关键掺杂元素的离子强度进行多次测定,计算平均结果,得到未校正的表观浓度,利用标准曲线法计算出关键杂质元素的相对灵敏度因子.     

Rapid analysis of pesticide residues in drinking water samples by dispersive solid‐phase extraction based on multiwalled carbon nanotubes and pulse glow discharge ion source ion mobility spectrometry

An analytical method based on dispersive solid‐phase extraction with a multiwalled carbon nanotubes sorbent coupled with positive pulse glow discharge ion mobility spectrometry was developed for analysis of 30 pesticide residues in drinking water samples. Reduced ion mobilities and the mass–mobility correlation of 30 pesticides were measured. The pesticides were divided into five groups to verify the separation capability of pulse glow discharge in mobility spectrometry. The extraction conditions such as desorption solvent, ionic strength, conditions of adsorption and desorption, the amounts of multiwalled carbon nanotubes, and solution pH were optimized. The enrichment factors of pesticides were 5.4‐ to 48.7‐fold (theoretical enrichment factor was 50‐fold). The detection limits of pesticides were 0.01～0.77 μg/kg. The linear range was 0.005–0.2 mg/L for pesticide standard solutions, with determination coefficients from 0.9616 to 0.9999. The method was applied for the analysis of practical and spiked drinking water samples. All results were confirmed by high‐performance liquid chromatography with tandem mass spectrometry. The proposed method was proven to be a commendably rapid screening qualitative and semiquantitative technique for the analysis of pesticide residues in drinking water samples on site.     

Detection of negative ions in glow discharge mass spectrometry for analysis of solid specimens

A new method is presented for elemental and molecular analysis of halogen-containing samples by glow discharge time-of-flight mass spectrometry, consisting of detection of negative ions from a pulsed RF glow discharge in argon. Analyte signals are mainly extracted from the afterglow regime of the discharge, where the cross section for electron attachment increases. The formation of negative ions from sputtering of metals and metal oxides is compared with that for positive ions. It is shown that the negative ion signals of F^? and TaO₂F^? are enhanced relative to positive ion signals and can be used to study the distribution of a tantalum fluoride layer within the anodized tantala layer. Further, comparison is made with data obtained using glow-discharge optical emission spectroscopy, where elemental fluorine can only be detected using a neon plasma. The ionization mechanisms responsible for the formation of negative ions in glow discharge time-of-flight mass spectrometry are briefly discussed.     

Determination of Silicate by Hollow Cathode Glow Discharge-Atomic Emission Spectrometry with Hydride Generation Technique

Abstract

Hollow cathode glow discharge atomic emission spectrometry has been applied to the determination of silicon coupled with a novel gaseous hydride generation technique, involving drying of an aqueous solution of silicate (sample) and mixing with powdered LiAlH₄. Sample introduction into the glow discharge chamber was performed via a pinhole at the center of the cathode which was connected to the hydride generator. The detection limit for silicon was 6μg at 288.1 nm and 30 μg at 251.6 nm.

     

Structures of NO 3 − formed via glow discharge in atmospheric gases

Tandem mass spectrometry experiments using both ion-molecule reactions and collision-induced dissociation (CID) in an ion trap mass spectrometer have been performed to characterize the structures of the NO ₃ ^? ions that issue from an atmospheric sampling glow discharge ionization source. The experimental evidence suggests that significant abundances of at least two stable forms of NO ₃ ^? can be obtained from an air-sustained glow discharge. Ab initio calculations have been performed to identify the structures of the likely isomers. Rate constants have been measured for the reaction of the less thermodynamically stable isomer(s) with carbon dioxide, and evidence is given for a new reaction, (OO?NO)^? + NO ₂ ^? → NO ₂ ^? + O₂ + NO^?. The combination of em with a kinetic study is shown to be a useful approach for obtaining rate constant information when a mixture of reactive and unreactive isomers is present in the reactant population.     

Laser ablation particle beam glow discharge time of flight mass spectrometry for the analysis of halogenated polymers and inorganic solid material

A laser ablation particle beam pulsed glow discharge mass spectrometer (LA-PB-GD-TOFMS) was designed and used for fundamental studies. The instrument consists of a three stage aerodynamic lens system, a hollow cathode pulsed glow discharge and a time-of-flight mass spectrometer. The particle beam interface was constructed to provide an efficient particle transfer into the hollow cathode. Calculations showed that particles between 1 and 3000 nm in diameter are able to pass through this interface.     

Time-of-flight mass spectrometry with pulsed gas-discharge ionization: Study of relative sensitivities of components

The potential of the relative sensitivity method was assessed for the direct analysis of solid samples using time-of-flight mass spectrometry with pulsed glow discharge ionization in a combined hollow cathode. Relative sensitivity factors of sample elements were obtained for various samples (copper, steel, nickel, lead, and silicon). For the majority of elements, these factors appeared to be close to unity. The factors were compared with the similar data obtained for direct current (DC) glow discharge; the range of factors obtained in the present work was significantly narrower. This opens up new prospects for pulsed gas-discharge ionization in semiquantitative analysis without using certified reference samples strictly corresponding to the test sample in composition and structure.