SDAT: analysis of <Superscript>131m</Superscript>Xe with <Superscript>133</Superscript>Xe interference

The Spectral Deconvolution Analysis Tool (SDAT) software was developed at The University of Texas at Austin. SDAT utilizes a standard spectrum technique for the analysis of β–γ coincidence spectra. Testing was performed on the software to compare the standard spectrum analysis technique with a region of interest (ROI) analysis technique. Experimentally produced standard spectra and sample data were produced at the Nuclear Engineering Teaching Laboratory (NETL) TRIGA reactor. The results of the testing showed that the standard spectrum technique had lower errors than the ROI analysis technique for samples with low counting statistics. In contrast, the ROI analysis technique outperformed the standard spectrum technique in high counting statistics samples. It was also shown that the standard spectrum technique benefitted from a compression of the number of channels within the spectra.     

Speciation of Aerosols by Combining Bulk Ion Chromatography and Thin-Window Electron Probe Micro Analysis

Size-fractionated aerosol samples were collected at De Panne, a coastal village east of the French industrial area of Dunkerque. The samples were treated and analysed with conventional ion chromatography (IC) analysis and with the relatively new and promising thin-window electron probe microanalysis (EPMA) technique. The output data of the chromatographic bulk analysis technique were compared with the results from the individual particle analysis technique after statistical processing. Both methods give specific and complementary information concerning the aerosol composition. Statistically interpreted information on the single particle scale can give a more qualitative interpretation of the quantitative bulk analysis data. In fact, it becomes possible to define and quantify a certain compound as a constituent of different aerosol types. On the other hand, the quantitative data of the bulk analysis helps the interpretation, validation and quantification of the output from the single particle technique. Especially in the case of coagulated aerosols, the IC technique is able to define and to quantify irresolvable clusters.     

On-line, inlet-based trimethylsilyl derivatization for gas chromatography of mono- and dicarboxylic acids

An on-line, inlet-based trimethylsilyl (TMS) derivatization technique was optimized and evaluated for quantitative analysis of mono- and dicarboxylic acids. The technique involves co-injection of sample and reagent followed by gas-phase formation of TMS derivatives and analysis by gas chromatography with flame ionization detection. Derivatization efficiencies were determined by comparing measured and theoretical effective carbon numbers and used to optimize the technique with respect to experimental parameters. For analysis of C5-C17 monocarboxylic acids and C2-C10 dicarboxylic acids under optimized conditions, average derivatization efficiencies were > or = 94%, average measurement uncertainties were < or = 5%, and detection limits were approximately 2 ng. The technique was applied to the analysis of carboxylic acids generated from the ozonolysis of cyclic alkenes in a smog chamber.     

HPLC柱切换技术在临床药物分析中的应用

综述了近十年来高效液相色谱柱切换技术在药物分析中的应用情况，主要介绍了柱切换技术在生物样品纯化，富集和手性分离方面的实际应用，该技术可用于直接进样分析，特别适用于临床药物分析，可和于药代动力学，生物利用度等研究。     

激光诱导击穿光谱:从实验平台到现场仪器

激光诱导击穿光谱(Laser-induced breakdown spectroscopy, LIBS)技术利用激光实现对分析样品的快速原位剥蚀和光谱激发,是一种具有广阔应用前景的分析手段,尤其是在现场、原位分析中优势明显,快速原位的分析特点符合未来分析仪器的发展方向.近年来基于该技术开展各类仪器研发的相关工作,引起广大研究者的极大关注.本文综述了激光诱导击穿光谱仪器中关键部件的组成及发展,从便携式、手持式及远程系统三个方面综述了各类现场应用仪器的研发进展,并对未来发展方向进行了展望.     

Potentiometric stripping analysis

The analytical possibilities of potentiometric stripping analysis are outlined. The technique comprises reduction of metal ions at a stationary mercury drop or thin-film electrode. The amalgamated metals are then re-oxidized with mercury(II) ions, and the time—potential behaviour of the mercury electrode is recorded. The technique is compared with d.c. and differential pulse anodic stripping analysis.     

傅立叶变换-主成份分析方法用于二维色谱数据的压缩和重构

结合傅立叶变换（ＦＴ）和主成份分析（ＰＣＡ）技术,实现了二维高效液相色谱数据的压缩和重构,并对不同信噪比的二维色谱测量数据进行了处理,即使对原始数据的压缩比高达２００倍,仍能很好地重构原始数据,当原始数据的信噪比较低时,阈值的选择受大振幅噪音的影响,使压缩比略有下降,但仍然能够保持信号基本不失真。     

现代测试技术在纳米材料研究中的应用

对电子显微技术、衍射技术、谱学技术及热分析技术的原理、特点及其在纳米材料中的应用作了评述。在此基础上指出：综合使用各种不同的分析和结构表征方法,可对纳米材料的结构和性能进行有效研究,从而指导其应用。     

Comparison of Differential Pulse Voltammetry (DPV)—a new method of carbamazepine analysis—with Fluorescence Polarization Immunoassay (FPIA)

Carbamazepine is a widely used anti-epileptic drug with narrow therapeutic range. Many methods have been developed for monitoring the serum drug level. Differential pulse voltammetry (DPV), an electrochemical method advantaged by simple, inexpensive, and relatively short analysis time, has recently been developed for carbamazepine detection. We used a newly developed DPV method with glassy carbon as a working electrode to determine the carbamazepine level. The performance of DPV is compared with the widely used fluorescence polarization immunoassay (FPIA) technique in precision, accuracy, linearity and detection limit. The precision, linearity and accuracy of the DPV and FPIA techniques were comparable at most clinical used levels. The detection limit was 1 μg/mL for the DPV technique and 0.5 μg/mL for the FPIA technique. The performance of the DPV technique was within the FDA guidelines for bioanalytical methods, which ensures the clinical applicability of the DPV technique. The DPV technique may have the potential to be a good alternative for carbamazepine analysis.     

Simultaneous determination of lithium, sodium and potassium in blood serum by flame photometric flow-injection analysis

A simultaneous flow-injection analysis (FIA) manifold that could analyse three ions from a single injection was designed, constructed, calibrated and used successfully to analyse Li(+), Na(+) and K(+). This FIA method was 10 times faster than the batch technique. The sample volume required was a fraction of about 1/110 to 1/75 that of the batch technique. The outputs were quite reproducible and calibration curves were linear. Results obtained for artificial sera compared favourably with the actual known concentrations of ions and results obtained in the analysis of eight natural human blood sera compared well with those obtained by the traditional batch technique.     

示波流动注射分析

将流动注射技术应用于示波分析，建立了示波流动注射分析，即动态示波分析法。设计了适用于示波分析的流通池，提出电压反馈的示波新技术，研究了新方法的重现性、检测限及影响去极剂峰高的各种因素。实验表明：新方法重现性好、简便、快速、灵敏，为示波测定的实际应用提供了可行的途径。     

Differential barothermal analysis (DBA) of Ni-base alloys

The technique of differential barothermal analysis (DBA) combines the hot isostatic pressing technique and classical differential thermal analysis has been elaborated. This technique allows the study of the phase equilibria in the most of inorganic systems under pressure up to 200 MPa and temperatures up to 2000°C. The Ni-base alloy with the solidus, liquidus, g-phase and carbides dissolution temperatures of 1328, 1390, 1272 and 1255°C, accordingly, was chosen as a model material. By DBA technique the pressure coefficients of the above mentioned temperatures were established. The values of the obtained coefficients are 3-5 times larger than the melting point pressure coefficient for the pure Ni (the alloy base metal). The discussion of the data obtained is carried out. This revised version was published online in July 2006 with corrections to the Cover Date.     

Fast temperature programming in routine analysis of multiple pesticide residues in food matrices

Flash gas chromatographic (GC) analysis of 15 organophosphorus pesticides commonly occurring in food crops was performed using the Thermedics Detection EZ Flash upgrade kit installed in the oven of a HP 5890 Series II Plus gas chromatograph. The temperature program and splitless time period were the main parameters to be optimized. In the first set of experiments wheat matrix-matched standards were analyzed both by: (i) the flash GC technique (resistive heating of a 5 m capillary column), and (ii) the conventional GC technique (moderate oven temperature programming of a 30 m capillary column). Using the flash GC technique, the analysis time was reduced by a factor of more than 10 compared to the conventional GC technique. Dramatically improved detectability of analytes was achieved due to much narrower peak widths. The flash GC technique was compared with another approach to faster GC analysis employing a 5 m column and fast temperature programming with a conventional GC oven. In comparison with this alternative, in the case of flash GC significantly better retention time repeatability was observed. The other superiority of resistive heating is very rapid cooling down (i.e., equilibration to the initial conditions) which contributes to the increased sample throughput.     

Method for improving accuracy in full evaporation headspace analysis

We report a new headspace analytical method in which multiple headspace extraction is incorporated with the full evaporation technique. The pressure uncertainty caused by the solid content change in the samples has a great impact to the measurement accuracy in the conventional full evaporation headspace analysis. The results (using ethanol solution as the model sample) showed that the present technique is effective to minimize such a problem. The proposed full evaporation multiple headspace extraction analysis technique is also automated and practical, and which could greatly broaden the applications of the full‐evaporation‐based headspace analysis.     

Dynamic dielectric analysis of solids

An automated technique has been developed which enables a rapid determination of the dielectric properties of a material over a wide range of temperatures and frequencies. The speed of data acquisition and the range of temperature and frequencies that can be investigated in a single experiment using this technique, exceed the capabilities of techniques currently employed for dielectric analysis. Frequencies for dielectric measurements can be pre-selected in increments over the range 50 Hz-1 MHz. Temperature range for these measurements extends from 25°C to 800°C. The present technique, which features extensive automation in data acquisition and processing, is illustrated by measurements on minerals and shales. The dynamic nature of the above technique also facilitates effective coupling with conventional thermal analysis techniques.     

Rapid drug detection in oral samples by porous silicon assisted laser desorption/ionization mass spectrometry

The demand for analysis of oral fluid for illicit drugs has arisen with the increased adoption of roadside testing, particularly in countries where changes in legislation allow random roadside testing of drivers for the presence of a palette of illicit drugs such as methamphetamine (MA), 3,4‐methylenedioxymethamphetamine (MDMA) and Δ⁹‐tetrahydrocannabinol (THC). Oral samples are currently tested for such drugs at the roadside using an immunoassay‐based commercial test kit. Positive roadside tests are sent for confirmatory laboratory analysis, traditionally by means of gas chromatography/mass spectrometry (GC/MS). We present here an alternative rapid analysis technique, porous silicon assisted laser desorption/ionization time‐of‐flight mass spectrometry (pSi LDI‐MS), for the high‐throughput analysis of oral fluids. This technique alleviates the need for sample derivatization, requires only sub‐microliter sample volumes and allows fast analysis (of the order of seconds). In this study, the application of the technique is demonstrated with real samples from actual roadside testing. The analysis of oral samples resulted in detection of MA and MDMA with no extraction and analysis of THC after ethyl acetate extraction. We propose that, subject to miniaturization of a suitable mass spectrometer, this technique is well suited to underpin the deployment of oral fluid testing in the clinic, workplace and on the roadside. Copyright © 2009 John Wiley & Sons, Ltd.     

Volatile enrichment on automatic static headspace using a precolumn and stopping the carrier gas flow during injection

The aim of this study was to develop a technique for performing automatic static headspace analysis of volatiles without a cryogenic device. Reconcentration of solutes was accomplished using a graphitized carbon coated precolumn between two splitting points and stopping carrier gas flow during injection. Chromatographic profiles of volatile compounds from ground coffee compared with split and splitless injections provide confirmation of the good sensitivity of the technique. The analysis of a standard mixture covering a wide range of volatility confirms that the described technique might be useful to achieve enrichement of low volatile headspace compounds, even if discrimination against the various components is present.     

Study of Pt-Re/alumina reforming catalysts by neutron activation analysis

The elemental analysis of Pt-Re/alumina catalysts was carried out by nondestructive and bulk neutron activation analysis. Samples were irradiated with a²⁴¹Am-Be source-based as well as accelerator-based thermal neutrons and induced activities were measured by a HPGe detector with a PC-based data acquisition and analysis system. An appropriate calibration technique was established for the determination of the respective ratios of each element present in the catalysts. The technique proved to be useful for the determination of low concentrations of Pt and Re in the catalyst samples.     

镁同位素分析技术应用于葡萄酒辨别的探索研究

建立了阳离子树脂富集镁的方法.以1 mol/L HNO3为淋洗液、AG W50-X8阳离子树脂富集镁.方法回收率为(101.6±1.2)％.以H2 (2.1 mL/min)、He(7.0 mL/min)混合碰撞气消除12C12 C+,12C21H+等干扰的MC-ICP-MS分析方法.分析了40种葡萄酒中镁同位素组成,结果表明:不同产地葡萄酒中镁同位素组成差异明显;而且,来自同一产区不同葡萄园的葡萄酒中镁同位素组成也有显著差异.这表明镁同位素具有区分不同产地葡萄酒的能力,而且地理分辨率较高.对于部分镁同位素组成差异不明显的样品,结合元素分析手段,可以准确区分.     

毛细管电泳-电感耦合等离子体质谱在痕量元素形态分析中的应用

叙述了元素形态分析的目的和意义以及发展概况，并在此基础上着重叙述了近年来毛细管电泳(CE)与电感耦合等离子体质谱(ICP-MS)联用技术在痕量元素形态分析上的应用，包括该联用技术的关键CE与ICP-MS接口的不同设计，影响CE分离分辨率及分析灵敏度的主要因素。对这种分析技术在元素形态分析上应用的潜力和限制以及发展趋势作了讨论。