辉光放电质谱新方法分析颗粒状金属铪

采用直流辉光放电质谱方法((dc-GD-MS)分析颗粒状((2mm×1mm×1mm)金属铪中的杂质元素.本方法解决金属铪样品尺寸太小难以直接进行辉光放电质谱分析的问题.采用聚四氟乙烯管(内径2.3 mm×外径3.2 mm)与医用注射器连接并密封接口,再将粒状铪置于管子前端(管长的1/3处),接着将PTFE 管水平插入已...     

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。     

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。     

辉光放电质谱分析中质谱干扰及其校正方法的现状

详细地介绍了辉光放电质谱分析中的质谱干扰如同量异位素、多原子离子和多电荷离子干扰。从同位素选择、高分辨率仪器、碰撞诱导解离、离子源冷却、数学方法校正、放电气体更换和放电气体纯度提高等方面对辉光放电质谱的质谱干扰校正方法的现状进行了评述(引用文献共68篇)。     

辉光放电质谱测量中的相对灵敏度因子研究

辉光放电质谱(GDMS)作为高纯金属和半导体材料分析的强有力工具在国内已得到了大量应用,该文简要介绍了GDMS的基本原理和国内外应用现状,对仪器测量条件的选择、测量重复性进行了详细研究,对于含量在1 mg/kg左右的杂质,测量的重复性将产生约1%～5%的不确定度;对不同金属基体的系列标准物质进行对比研究,发现对于基体相同的样品,杂质元素在较宽的浓度范围内可以使用同样的校正系数进行校正,大部分元素的线性相关系数达到0.999以上,但对于不同基体的样品,测量中仍存在明显的基体效应,一些元素,尤其是轻质量数元素的相对灵敏度因子(RSF)设定值存在较大的偏差,并不适合定量分析,但绝大部分不超过2倍误差,可以满足半定量分析的要求。通过对GDMS定量分析中关键因素的研究,认为相对灵敏度因子的校正是GDMS测量结果可溯源性的关键。     

微型辉光放电等离子体用于质谱成像分析的初步研究

本实验利用实验室自主研发的微型辉光放电等离子体(MFGDP)作为离子源解吸样品,使之离子化,得到样品的特征质谱图,经特定软件的转化即可得到对应的图像,图像表明,MFGDP用于质谱成像具有可行性.本方法具有装置简单、操作简易、等离子体羽低温、分析时间短(＜20 min)等优点,可同时定位样品中不同物质的空间分布.本研究探讨了影响质谱成像图清晰度的因素,优化了实验条件,在最优条件下,本方法的空间分辨率约300μm,对加有尿素的不同字迹进行初步质谱分析,并对冬枣切片中硬脂酸和槲皮素衍生物的空间分布做了影像探索.此技术可以根据化学物质的指纹图谱区分不同的字迹,也能够很好地获取样品中不同营养物质的分布状况,因此,为字画研究、艺术品鉴定、营养物质分布图的获取提供了一种新的方法.     

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。     

辉光放电光谱法在深度分析上的应用现状

本文简单地介绍了辉光放电光谱法（GD-OES）的基本原理。分别对深度分析的定量方式、放电方式、应用领域和相关标准进行了详细地阐述。重点描述了商品化仪器中使用的SIMR深度分析定量方法。分别对三种放电方式（如直流、射频和脉冲）在深度分析中的特点进行了介绍。综述了GD-OES在金属镀层、复杂涂镀层、纳米级薄膜和样品制备领域的具体应用。最后,介绍了GD-OES在深度分析方面的标准     

大气采样辉光放电质谱仪的设计与应用

针对某些弱极性类物质难以通过大气压离子源直接电离的问题,提出基于大气采样辉光放电电离方式实现弱极性物质在大气压下直接进样、电离和质谱分析的方法.通过在大气压接口-四极质谱仪的第一级真空中的离子透镜上施加交流高压产生放电,简化了辉光放电离子源的设计,能直接离子化大气压接口吸人的物质,离子在离子透镜的传输下进入四极杆质量分析器实现质谱分析.实验表明,本方法能电离电喷雾电离离子源和大气压化学电离离子源未能电离的弱极性物质——艾试剂,并且负离子工作模式比正离子工作模式的信号至少强40倍.     

充氘钯空心阴极灯中放电气体的质谱研究

充氘钯空心阴极灯中放电气体的质谱研究杨原，王小如（厦门大学化学系，厦门，３６１００５）关键词充氘钯阴极，辉光放电，氦－４质谱钯吸附氢气及氘气的研究已有报道［１］，在一定操作条件下，钯吸附氘后还可能产生异常效应［２］。金属空心阴极灯已被广泛地应用于物理...     

Analysis of semiconducting materials by high-resolution radiofrequency glow discharge mass spectrometry

The analytical capabilities of a high-resolution mass spectrometer in combination with a 13.56 MHz glow discharge ion source for the analysis of semiconducting materials (silicon carbide and gallium arsenide) were studied. It was shown that single positively charged ions of sample material have about 10 eV higher average energy than the ions of the discharge and residual gas. Therefore effective energy separation of the ions of analyte from the ions of the discharge and residual gas was achieved by adjusting the ion transfer optics (breadth and position of energy slit), which improves the analytical capabilities of the developed method.Some analytical applications are presented to illustrate the performance of r.f. GDMS for the bulk analysis of semiconducting materials. The results of the trace element analysis of gallium arsenide and silicon carbide samples are compared with data of independent methods (LIMS, ICP-AES, SIMS).Dedicated to Professor Dr. rer. nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthdayOn leave from the Institute of Inorganic Chemistry, 630090 Novosibirsk, Russia     

辉光放电质谱法测定核级石墨粉中痕量杂质

建立了直流辉光放电质谱法(DC-GDMS)测定核级石墨粉中痕量杂质元素的方法。用一定的压力将石墨粉镶嵌在高纯铟片上,形成一个直径约为5 mm的圆形石墨薄层,用铟片辅助石墨粉放电,实现了粉状样品直接检测。优化的实验条件为放电电流0.8 mA,放电电压1.2 kV,放电气体流速0.437 mL/min。用石墨粉标准样品(19J T61029)单点校准了仪器相对灵敏度因子,消除基体效应,实现15个关键杂质元素定量分析。方法检出限为5.0 ng/g,在单侧0.05显著性水平下,利用Student’s t检验,方法测定结果 t值均小于临界值,与标准值无显著性差异。相对标准偏差(RSD)均小于10%。本方法与电感耦合等离子体光谱法测定结果比较,相对误差在2.4%～17.4%之间。     

The laser as an analytical probe in glow discharge mass spectrometry

A pulsed dye laser was used alone and in combination with an auxiliary glow discharge for diagnostic studies. We have compared the mass ablation rate and ion signal in high vacuum and in the presence of an ambient buffer gas. Laser pulse energy and repetition rate were studied over the analytical range of the system. The effect of ambient gas pressure on redeposition was determined for three different gases: helium, neon, and argon. The laser/auxiliary discharge system was also shown to have analytical utility for the analysis of nonconducting samples. Spectra are included to illustrate the enhancement of the laser atomization/discharge ionization scheme over laser atomization/ionization.Presented in part at the 1989 European Winter Conference on Plasma Spectrochemistry, Reutte, Austria     

Spectroscopic evaluation of a compact magnetically boosted radiofrequency glow discharge for time-of-flight mass spectrometry

A compact magnetically boosted radiofrequency glow discharge (GD) has been designed, constructed and its analytical potential evaluated by its coupling to a mass spectrometer (MS). Simple modifications to the original source configuration permitted the insertion of permanent magnets. Small cylindrical Nd–Fe–B magnets (∅ = 4 mm, h = 10 mm) were placed in an in-house-modified GD holder disc that allows easy and fast exchange of the magnets. The different processes taking place within the GD plasma under the influence of a magnetic field, such as sputtering, ionisation processes and ion transport into the MS, were studied using different GD operating conditions. Changes to the ionisation and ion transport efficiency caused by the magnetic field were studied using an rf-GD-TOFMS setup. A magnetic field of 60–75 gauss (G) was found not to affect the sputtering rates but to enhance the analyte ion signal intensities while decreasing the Ar species ion signals. Moreover, magnetic fields in this range were shown not to modify the crater shapes, enabling the fast and sensitive high depth resolved analysis of relatively thick coated samples (micrometre) by using the designed compact magnetically boosted rf-GD-TOFMS.

辉光放电质谱法定量测定重掺晶体硅中替位碳含量

采用辉光放电质谱法测定单晶硅中替位碳含量,通过优化仪器工作条件,得到最佳放电参数.利用低温傅里叶变换红外光谱法对呈梯度的四个单晶硅片中替位碳含量进行赋值,将辉光放电质谱法测得替位碳强度与硅的离子束比与赋值结果作工作曲线,计算得到相对灵敏度因子(RSFcal)为1.19.在优化过的工作条件下,用辉光放电质谱法测未知样,用...     

RF-pulsed glow discharge time-of-flight mass spectrometry for glass analysis: Investigation of the ion source design

Radiofrequency (RF) millisecond pulsed glow discharge (PGD) coupled to time-of-flight mass spectrometry (TOFMS) was investigated for direct elemental analysis of glass samples. Aiming at achieving highest elemental sensitivity, appropriate discrimination from polyatomics, and good crater shapes on glasses, a new Grimm-type GD chamber (termed from now “UNIOVI GD”, designed and constructed in our laboratory) was coupled to TOFMS, and the results compared with those obtained with the former GD design (here denominated as “GD.1”) of the initial RF-PGD-TOFMS prototype. The critical differences distinguishing the two GDs under scrutiny are the GD chamber thickness (15.5 mm for the GD.1 and 7 mm for the UNIOVI GD) and the “flow tube” which is inserted in the GD.1 and inexistent in UNIOVI GD.     

Model of microsecond pulsed glow discharge in hollow cathode for mass spectrometry

A new model for microsecond pulsed glow discharge in a hollow cathode and its afterglow is described. The model is based on the Monte-Carlo method together with a new method for electrical field calculation, which is based on some phenomenological laws of plasma behavior. The afterglow model uses continuity and Poisson equations. A qualitative agreement between the model results and results published in experimental and theoretical works is demonstrated. Some processes in the microsecond pulsed discharge in the hollow cathode, such as sputtering, ionization and transfer of sample, are investigated. The model is successfully used for the optimization of the operational parameters of the time-of-flight mass spectrometer with ionization by microsecond pulsed glow discharge in a hollow cathode.     

Evaluation of pulsed radiofrequency glow discharge time-of-flight mass spectrometry for precious metal determination in lead fire assay buttons

In this paper, an exploration of the capabilities and limitations of pulsed radiofrequency glow discharge time-of-flight mass spectrometry (GD-TOFMS) for the determination of the precious metals Ag, Au, Pd, Pt and Rh in lead buttons obtained by Pb fire assay is reported on. Since the matrix consists almost entirely of lead (>99%), the occurrence of doubly charged Pb (Pb²⁺) ions can hinder accurate determination of Rh. This problem was counteracted by relying on the time-resolved formation of different ion types over the pulse period of the glow discharge, which allows discrimination against the Pb²⁺ ions. The formation of ArCu⁺ ions as a result of the use of a copper anode was assessed to pose no threat to the accuracy of the results obtained for the set of samples analyzed as its contribution to the total signal at m/z = 103 could be adequately corrected for. The method developed was evaluated in terms of accuracy and precision using a set of Pb button standards with analyte concentrations between 5 and 100 μg g⁻¹. For the purpose of validation, a 10 μg g⁻¹ standard was considered as a sample. Overall, an acceptable accuracy was obtained with a bias of <5% between the experimental results and the corresponding reference values, except for Au, for which a larger deviation occurred. Precision values (repeatability) of typically <5% relative standard deviation (RSD) (for N = 3) were obtained and the limits of detection (LODs) vary from ∼0.020 μg g⁻¹ for Ag to ∼0.080 μg g⁻¹ for Pt.     

Investigation of the afterglow time regime in pulsed radiofrequency glow discharge time‐of‐flight mass spectrometry

The pulsed power operation mode of a radiofrequency (rf) glow discharge time‐of‐flight mass spectrometer was investigated, for several ions, in terms of intensity profiles along each pulse period. Particular attention was paid to the plateau and transient afterglow regions. An rf pulse period of 4 ms and a duty cycle of 50% was selected to evaluate the influence of discharge parameters in the afterglow delay and shape of Ar⁺, Ar₂⁺ and several analytes (Br, Cl, Cu) contained in polymeric layers. Pulse shapes of Ar⁺ and Ar₂⁺ ions vary with pressure and power. At low pressures the highest intensity is observed in the plateau while at higher pressures (>600 Pa) the afterpeak is the dominant region. Although the influence of the applied power is less noticeable, a widening of the afterglow time regime occurs for Ar⁺ when increasing the power. Maximum intensity of the argon signal is measured in the afterglow at 30 W, while the area of such afterpeak increases with power. The maximum intensity of Ar₂⁺ is obtained at the highest power employed (60 W) and the ratio maximum intensity/afterglow area remains approximately constant with power. Analytes with ionization potentials below (Cu) or just above (Br) the argon metastable energy show maxima intensities after argon ions decay, indicating they could be ionized by collisions with metastable Ar atoms. Chlorine signals are observed in the afterglow despite their ionization potential is well above the energy of argon metastable levels. Moreover, they follow a similar pattern to that observed for Ar₂⁺, indicating that charge‐transfer process with Ar₂⁺ could play a significant role. Copyright © 2011 John Wiley & Sons, Ltd.