Measurement of the Oxygen and Impurity Distribution in Polycrystalline Aluminum Nitride with Secondary Ion Mass Spectrometry

The lattice oxygen content in sintered polycrystalline aluminum nitride substrates was measured via secondary ion mass spectrometry (SIMS). This was achieved by quantitative analysis of spatial and depth-resolved ion images of polished specimens using the solid-state standard addition method. The thermal conductivity of the polycrystalline material, measured with the laser flash technique, was found to be strongly correlated with the oxygen content in the AIN grains. This dependence is similar to that observed in single-crystal studies and is consistent with the phonon scattering model of AIN thermal conductivity. Scanning electron microscopy and SIMS images of a variety of other species (C, F, Cl, Y, Si, and Ca) were also obtained. In general, impurities were localized within second-phase regions although calcium was also found to be distributed uniformly along AIN grain boundaries. Other impurity constituents are also discussed.     

Application of Secondary Ion Mass Spectrometry to Adhesion Studies

The present paper firstly describes developments in the technique of static secondary ion mass spectrometry. Secondly, the power of this advanced surface analytical technique is illustrated by discussing the locus of failure of epoxide/polyethylene substrate joints.     

Application of Secondary Ion Mass Spectrometry to Adhesion Studies

The present paper firstly describes developments in the technique of static secondary ion mass spectrometry. Secondly, the power of this advanced surface analytical technique is illustrated by discussing the locus of failure of epoxide/polyethylene substrate joints.     

A Reliable Approach for Revealing Molecular Targets in Secondary Ion Mass Spectrometry

Nano secondary ion mass spectrometry (nanoSIMS) imaging is a rapidly growing field in biological sciences, which enables investigators to describe the chemical composition of cells and tissues with high resolution. One of the major challenges of nanoSIMS is to identify specific molecules or organelles, as these are not immediately recognizable in nanoSIMS and need to be revealed by SIMS-compatible probes. Few laboratories have generated such probes, and none are commercially available. To address this, we performed a systematic study of probes initially developed for electron microscopy. Relying on nanoscale SIMS, we found that antibodies coupled to 6 nm gold particles are surprisingly efficient in terms of labeling specificity while offering a reliable detection threshold. These tools enabled accurate visualization and sample analysis and were easily employed in correlating SIMS with other imaging approaches, such as fluorescence microscopy. We conclude that antibodies conjugated to moderately sized gold particles are promising tools for SIMS imaging.     

Silica and Magnesia Dopant Distributions in Alumina by High-Resolution Scanning Secondary Ion Mass Spectrometry

Trace SiO₂ and MgO additive distributions in sintered alumina have been studied using high-resolution scanning secondary ion mass spectrometry (SIMS). When doped with each additive individually, evidence is seen for both strong silicon segregation to grain boundaries ( C _gb/ C _grain similar/congruent 300) in SiO₂-doped alumina and strong magnesium segregation to grain boundaries ( C _gb/ C _grain similar/congruent 400) in MgO-doped alumina. When codoped with both SiO₂ and MgO, segregation of both ions to grain boundaries is reduced by a factor of 5 or more over single doping. The additive concentrations increase proportionally in the grains, and both dopants become more uniformly distributed throughout the bulk. It is concluded that codoping with these additives increases their mutual bulk solid solubility and decreases their interfacial segregation over single doping. The beneficial effect of MgO additions in controlling microstructure development in alumina and improving corrosion resistance to aqueous HF stems from its ability to redistribute silicon ions from grain boundaries into the bulk.     

Determination of Mass Transport Mechanism of Rutile by Sinusoidal Profile Decay Method

Amplitude decay of sinusoidal surface profiles on the c surface of TiO₂ single crystals was measured in air over the range 1500 to 1700 K. The rate of decay was proportional to –2.75 powers of the sinusoidal wave length (4.3 to 17.6 μrn), indicating that volume diffusion is the dominant mass-transport mechanism. The effective volume diffusion coefficient, Deff , given agreed with tracer diffusion data for the Ti ion. Hence Deff was assumed to be equal to the self-diffusion coefficient of the Ti ion as oxygen ion transport along the surface was enhanced. No anisotropy was observed for transport on this surface.     

Secondary Ion Mass Spectroscopy Study of Oxygen-18 Tracer Diffusion in 2/1-Mullite Single Crystals

Oxygen ¹⁸O tracer diffusion in Czochralski-grown mullite single crystals is investigated along [010] and [001]. Oxygen diffusion coefficients range between ∼5 × 10⁻²⁰ m²/s (1250°C) and ∼9 × 10⁻¹⁸ m²/s (1525°C). The data does not show any significant anisotropy. The values of the activation enthalpy (4.5 eV) and of the activation entropy ((3.4 ± 1.6) k _B, where k _B is the Boltzmann constant) suggest that the atomic transport occurs via thermally activated vacancies.     

Tandem Mass Spectrometry in the Technology of Determining Aralosides of Phytoadaptogene Compositions

Theoretical Foundations of Chemical Engineering - The possibilities of tandem mass spectrometry have been studied for the technology of analyzing aralosides in the pharmaceutical composition of...     

能量色散X射线荧光光谱法分析镀液中金离子的质量浓度

采用能量色散X射线荧光光谱法(EDXRF)对镀液中金离子的质量浓度进行定量分析,介绍了标样的配制方法和镀液的分析方法,并与化学分析法的测定结果进行了对比。结果表明:该方法具有较高的准确度和精密度,操作方便,为检测镀液中金离子的质量浓度提供了新的手段。     

气相色谱/质谱法测定猪肉中莱克多巴胺回收率低的原因分析

农业部958号公告-4-2007中给出了检测猪肉中莱克多巴胺残留量的气相色谱-质谱法,但在做加标回收实验时(向5 g样品中添加200 ng莱克多巴胺标准物质),其平均回收率仅为50%左右,回收率较低。在本实验室技术水平基础上,对影响回收率的关键步骤进行分析,找出回收率低的原因。     

Use of Ion Scattering and Secondary Ion Mass Spectrometry to Characterize Apparent “Adhesive” Failure in an Adhesive Bond

Frequently it is not easy using visual or even microscopic examination of an adhesive joint to determine after physical testing whether an apparent adhesive failure occurred at the original interface due to improper wetting or at some new interface leaving behind a thin layer of adhesive. Elemental analysis techniques such as ion scattering spectrometry (ISS) and secondary ion mass spectrometry (SIMS) are easily capable of determining the locus of failure in an adhesive joint. The use of these two techniques in combination is shown for investigating adhesive bonding phenomena. The operating parameters as well as advantages and disadvantages of each are summarized. ISS-SIMS data are shown for two adherend surfaces which broke in a lap shear test by apparent cohesive failure in both the adhesive and adherend.     

Evaluation of pervaporation process of kiwifruit juice by SPME-GC/Ion Trap Mass Spectrometry

The processing of kiwifruit for obtaining products with a higher sensory quality, to be used in the food industry, is associated with the use of techniques which can limit the physical and chemical losses of aroma compounds. Pervaporation (PV) represents an alternative to the techniques based on distillation/evaporation or partial condensation to concentrate the aroma compounds preserving the molecule integrity (mild operational conditions used), having a high selectivity towards the organic volatile compounds, and respecting also the environment. The most representative volatile compounds of the kiwifruit aroma was chosen for evaluating the pervaporation process. SPME‐GC/ion trap mass spectrometry method was exploited to determine the amounts of these compounds. The approach was based on chemical ionization acquisition with isobutane as reagent gas and 1‐heptanol and (Z)‐3‐hexen‐yl acetate as internal standards. In these conditions, the calibration curves were satisfactory as demonstrated by the R² values of the straight lines (0.9937-0.9999). A kiwifruit fresh juice was processed by pervaporation through the composite commercial membrane (GFT1070) and the one self‐prepared, made of styrene butadiene co‐styrene (SBS), at three different feed temperatures. Marked effects for both membranes were observed in the total and partial fluxes of aroma compounds as the temperature was increased. The studied aroma compounds were differently affected by the temperature changes during PV process, with the result of a change in concentration in the permeate of the aroma compounds recovered.     

气相色谱-质谱联用法测定食品用硅油纸中氢化三联苯的迁移量

建立了气相色谱-串联质谱快速检测食品用硅油纸中氢化三联苯迁移量的方法。样品经迁移液浸泡后,用气相色谱-质谱仪进行测定,外标法定量。采用HP-5MS柱(30m×0.25mm×0.25μm)进行分离,进样口温度为250℃,氦气流速为1.0mL/min。氢化三联苯在1.0～25.0μg/mL浓度范围内呈良好的线性关系,方法的检出限(LOD,S/N=3)为0.15μg/mL,定量限(LOQ,S/N=10)为0.5μg/mL。50%乙醇迁移液的三个加标水平的平均回收率为85.6%～90.6%,相对标准偏差为5.7%～7.2%(n=6);异辛烷迁移液的三个加标水平的平均回收率为91.4%～95.6%,相对标准偏差为5.7%～6.9%(n=6)。该方法具有优良的灵敏度及稳定性,满足食品用硅油纸中氢化三联苯的分析检测和准确定量。     

Erratum to: Tandem Mass Spectrometry in the Technology of Determining Aralosides of Phytoadaptogene Compositions

Theoretical Foundations of Chemical Engineering - An Erratum to this paper has been published: https://doi.org/10.1134/S0040579521310018     

UML面向对象建模在质谱仪测控系统中的应用

首先简要介绍面向对象方法和UML(统一建模语言)建模机制的特点,接着在VG5400稀有气体质谱仪测控系统结构的基础上,先深入分析系统工作原理和功能需求,再基于UML面向对象建模机制对样品分析子系统进行了分析建模,包括用例建模、静态建模和动态建模,分别建立了用例图、类图和顺序图。所得的分析模型为进一步建立设计模型奠定了基础。     

Direct Analysis in Real Time (DART) of an Organothiophosphate at Ultrahigh Resolution by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry and Tandem Mass Spectrometry

Direct analysis in real time (DART) is a recently developed ambient ionization technique for mass spectrometry to enable rapid and sensitive analyses with little or no sample preparation. After swab-based field sampling, the organothiophosphate malathion was analyzed using DART-Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry (MS) and tandem mass spectrometry (MS/MS). Mass resolution was documented to be over 800,000 in full-scan MS mode and over 1,000,000 for an MS/MS product ion produced by collision-induced dissociation of the protonated analyte. Mass measurement accuracy below 1 ppm was obtained for all DART-generated ions that belonged to the test compound in the mass spectra acquired using only external mass calibration. This high mass measurement accuracy, achievable at present only through FTMS, was required for unequivocal identification of the corresponding molecular formulae.     

Measurement of the Effective Diffusivity in Porous Media by the Diffusion Cell Method

There has been a vast amount of investigation in the field of experimental and theoretical treatments of the effective diffusivity in porous media for more than half of a century [1-4]. The effective diffusivity is required for several reasons [5]; for example, during catalyst formulation, active species can be laid down precisely or with specified concentration profiles on a porous matrix or support. In experimental work on heterogeneous reactions an effective diffusivity is needed to obtain the value of the Thiele modulus and hence to determine the intrinsic reaction kinetics. In reactor design the diffusivity is needed to evaluate the Thiele modulus, which can then be an aid in predicting reaction rates for heterogeneous systems. In addition, a simple and quick testing method could be used as a screening or quality control procedure during catalyst manufacture.

     

ICP-MS测定多晶硅基体中金属杂质的不确定度评定

建立ICP-MS测定多晶硅基体中金属杂质Cr、Fe、Ni、Cu、Zn含量的不确定度评定法是多晶硅分析检测行业所迫切需求的。从样品称量、样品溶液的体积变化、仪器测量标准曲线和样品溶液中各杂质元素的浓度、以及整个试验过程中测量重复性引入的不确定度进行分析评定,依次得出分量标准不确定度,以分量标准不确定度计算出合成标准不确定度,并应用A类不确定度评定法计算出测量结果的扩展不确定度,并得出检测结果的置信区间。     

Measurement of the Effective Diffusivity in Porous Media by the Diffusion Cell Method

There has been a vast amount of investigation in the field of experimental and theoretical treatments of the effective diffusivity in porous media for more than half of a century [1-4]. The effective diffusivity is required for several reasons [5]; for example, during catalyst formulation, active species can be laid down precisely or with specified concentration profiles on a porous matrix or support. In experimental work on heterogeneous reactions an effective diffusivity is needed to obtain the value of the Thiele modulus and hence to determine the intrinsic reaction kinetics. In reactor design the diffusivity is needed to evaluate the Thiele modulus, which can then be an aid in predicting reaction rates for heterogeneous systems. In addition, a simple and quick testing method could be used as a screening or quality control procedure during catalyst manufacture.