氧—火焰离子化检测器的研制及应用

本文介绍选择测定复杂有机混合物中各含氧化合物的氧－火焰离子化（Ｏ－ＦＩＤ）检测器，该仪器是专门对氧响应的Ｏ－ＦＩＤ检测器，还报道了在Ｏ－ＦＩＤ检测器上对含氧化合物的定量校正工作。     

双波长K系数-标准加入-导数分光光度法同时测定重油中的钴镍

本文提出了一种同时测定两组分混和物的新方法，即双波长Ｋ系数－标准加入－导数分光光度法，该法同时进行两组分的标准加入，以两个组分的峰值波长为测定波长，又互为参比波长，利用Ｋ系数法以一套吸光度数据同时完成两个组分的测定。本文以ＯＰ－５－Ｂｒ－ＰＡＤＡＰ为显色体系，同时测定了重油中的钴、镍，结果令人满意。本方法简便，灵敏度高。     

反相高效液相色谱法同时测定动物血浆中泰乐松注射液的多种组分

研究了用反相高效液相色谱法分析动物血中泰乐松注射液中三种组分氯霉素、醋酸氢化泼尼松和酒石酸泰乐菌素浓度的方法，，血药由甲醇－氯仿混合液提取，采用ＯＤＳ柱，以甲醇－腈－醋酸钠溶液为流动相，可变波长检测。     

高效液相色谱法测定荧光增白剂OB

本文建立了高效液相色谱测定荧光增白剂ＯＢ，即２．５－双（５－叔丁基－２－苯并恶唑基）噻吩的方法。采用ＹＷＧ Ｃ１８色谱柱，四氢呋喃－水（６７：３３Ｖ／Ｖ）为流动相，流速１．０ｍＬ／ｍｉｎ，紫外检测波长３６０ｎｍ，柱温４０℃，分离时间少于１１ｍｉｎ。应用于工业产品的测定，结果满意。     

反相高效液相色谱法半制备分离[T(4-MOP)PS4]卟啉的研究

本文研究了新水溶性５，１０，１５，２０－四（４－甲氧基－３－磺酸苯基）卟啉［Ｔ（４－ＭＯＰ）ＰＳ４］的反相高效液相色谱（ＨＰＬＣ）分离条件。采用ＳｈｉｍｐａｃｋＰＲＥＰ－ＯＤＳ半制备色谱柱，用含有１０ｍｍｏｌ／Ｌ四乙基碘化铵的乙腈－水（体积比２５：７５）为流动相，流速１８ｍＬ／ｍｉｎ，于４１８ｎｍ波长下检测。［Ｔ（４－ＭＯＰ）ＰＳ４］与合成中生成的杂质组分完全分离。经此制备的卟啉纯度高，已成功地应用于自来水样中微量钴、锌、铜离子的ＨＰＬＣ测定中。     

反相色谱法分离和间接光度法测定无机阴离子

在化学键合固定相ＯＤＳ柱上,用Ｆｅ（Ｐｈｅｎ）_３~（２＋）作流动相添加剂分离并用间接光度法检测无机阴离子。探讨了主要因素（如流动相中Ｆｅ（Ｐｈｅｎ）_３~（２＋）浓度、有机溶剂浓度、ｐＨ值和离子强度等）对阴离子保留和检测灵敏度的影响。Ｃｌ~－,Ｂｒ~－,ＮＯ_３~－和Ｉ~－具有良好的分离度;间接光度检测波长为Ｆｅ（Ｐｈｅｎ）_３~（２＋）的最大吸收波长５１０ｎｍ。测定这４个离子的校正曲线的线性范围为１～１６０ｍｇ／Ｌ（Ｃｌ~－,Ｂｒ~－,ＮＯ_３~－）和２～３２０ｍｇ／Ｌ（Ｉ~－）;相关系数均达０．９９６。     

荧光素荧光猝灭法测定微量碘酸根

报道了荧光素为指示剂荧光猝灭法间接测定ＩＯ３－的方法。在０．０５ｍｏｌ／ＬＨ２ＳＯ４介质中，Ｉ－和ＩＯ３－反应生成Ｉ２，I２与荧光素反应、使荧光素荧光猝灭。该体系的激发波长和发射波长分别为４９３ ｎｍ和５１４ ｎｍ。ＩＯ３含量在２～８０ μｇ／Ｌ范围内有良好的线性关系，测定下限为 ２ μｇ／Ｌ。该法灵敏度高，选择性好，操作简单。用于含碘食盐、低钠食盐中微量ＩＯ３的测定，结果满意。     

采用粉末微电极技术改善电流型酶电极的输出性能

由于酶反应的特异性，酶电极在检测生物底物的工作中得到了较广泛的应用，然后电流型酶电极有以下的缺点，包括响应电流低，活性组份流失电极使用寿命下降以及响应电流的非线性等。本文根据粉末酶电极模型进行了动力学分析，得出在两极极端情况下粉末酶电极的电流响应动力学公式，以及由响应电流估算表观米氏常数的方法。采用了两种粉末酶电极（Ｃ－ＰＵ－ＧＯＤ和Ｃ－ＡＱ－ＤＢＦ－ＧＯＤ）对理论分析进行了验证。实验结果与理论推     

5,10,15,20—四（3—溴—4—磺酸苯基）卟啉高效液相色谱法测定河水中微量…

研究了新合成的显色剂５，１０，１５，２０－四（３－溴－４－磺酸苯基）卟啉与Ｃｏ（Ⅱ）、Ｚｎ（Ⅱ）、Ｃｕ（Ⅱ）形成配合物离子的反应，在ＺＯＲＢＡＸ ＯＤＳ柱上，用含２０ｍｍｏｌ／Ｌ乙酸－乙酸钠（ｐＨ６．０）和１０ｍｍｏｌ／Ｌ四乙基碘化铵的乙腈－水（２７：７３，Ｖ／Ｖ）流动相洗脱，在４２０ｎｍ波长下检测。Ｃｏ（Ⅱ）、Ｚｎ（Ⅱ）、Ｃｕ（Ⅱ）螯合物在９ｍｉｎ内获得完全分离，检测限分别为０．２ｎｇ，０．０５     

二溴羟基苯基荧光酮—乳化剂OP荧光熄灭法测定微量铬（Ⅵ）

本文基于Ｃｒ（Ⅵ）－二溴羟基苯基荧光酮（ＤＢＨ－ＰＦ）－ＯＰ体系的荧光熄灭效应，提出一种测定痕量铬（Ⅵ）的新荧光方法。在ｐＨ２．４－４．１的ＨＣｌ－ＮａＡｃ缓冲介质和ＯＰ存在下，Ｃｒ（Ⅵ）与ＤＢＨ－ＰＦ形成１：２的橙红色络合物，络合物的最大激发发工和发射波长分别是３６５ｍｍ和５２８ｎｍ。铬（Ⅵ）量在０．０５－１．５μｇ／２５ｍｌ范围内与△Ｆ呈线性关系，检测限是２．０ｎｇ／ｍｌ。方法用于电镀废液，废     

Design,construction and assessment of a field-deployable laser-induced breakdown spectrometer for remote elemental sensing

A field-deployable laser-induced breakdown spectrometer for measurements in the hundreds of meters range has been presented. The system is capable of elemental analysis with no previous preparation and in near real time, with the only requirement of a free line-of-sight between the instrument and the sample. Main factors influencing LIBS performance at stand-off distances are outlined. LIBS signal is shown to depend on range of analysis, peak power, beam quality, laser wavelength and optics dimensions. A careful control of focusing conditions has been shown to be of importance to avoid interferences from air breakdown by the stand-off focused beam.     

Effect of the Wavelength of the Laser Beam on the Response of an Evaporative Light Scattering Detector

Abstract

The effects of the wavelength of the laser beam on the response of an evaporative light scattering detector (ELSD) are discussed. Data characterizing the response of the detector and its dependence on the sample size have been collected for six solutes, using a pulsed dye laser as light source. The experimental results suggest that there is little influence of the wavelength on the intensity of the scattered light. On the other hand, the noise decreases in proportion to the wavelength of the incident light beam. Thus, the detection limit (at constant value of the signal to noise ratio) decreases with decreasing wavelengths. The performance of the ELSD improves when a short wavelength is used.     

Fluorescence cross-correlation spectroscopy using single wavelength laser

In this paper, we first introduced the basic principle of fluorescence cross-correlation spectroscopy (FCCS) and then established an FCCS setup using a single wavelength laser. We systematically optimized the setup, and the detection volume reached about 0.7 fL. The homebuilt setup was successfully applied for the study of the binding reaction of human immunoglobulin G with goat antihuman immunoglobulin G. Using quantum dots (745 nm emission wavelength) and Rhodamine B (580 nm emission wavelength) as labeling probes and 532 nm laser beam as an excitation source, the cross-talk effect was almost completely suppressed. The molecule numbers in a highly focused volume, the concentration, and the diffusion time and hydrodynamic radii of the reaction products can be determined by FCCS system. __________ Translated from Chemical Journal of Chinese Universities, 2008, 29(5) (in Chinese)     

Laser and synchrotron-based sources for excited state intramolecular dynamics studies

Energy ranges and time scales for excitation and relaxation of intramolecular processes are discussed and compared with the operational characteristics of laser and synchrotron radiation sources. The basic physics of synchrotron radiation and undulator emission is presented. It is shown how undulators can be used to generate short wavelength harmonics. Free electron lasers of the Compton and Raman scattering types and the associated electron beam sources are described. The properties and applications of free electron lasers are reviewed.     

Background correction in atomic emission spectrometry using repetitive harmonic wavelength scanning and applying Fourier analysis—I. Theory

Repetitive wavelength scanning can be used as a means of detecting and correcting for unwanted background in atomic emission spectrometry (AES). This paper deals with the theory underlying such harmonic wavelength scanning in time and stresses the relative importance of the relevant parameters. A set of integrated Turbo Pascal programs for an IBM PC was developed to provide a numerical simulation for the deconvolution of a detected spectral profile during repetitive harmonic wavelength scanning. By applying this numerical analysis the theory for separating the net spectral emission signal and the background radiation by filtering specific frequency components is investigated. It is concluded that, barring the dc component, repetitive scanning over a symmetric spectral profile leads to the generation of even-numbered Fourier harmonics at the modulation frequency, while an asymmetric spectral profile generates odd-numbered Fourier harmonics.     

Photodissociation of nitrous oxide starting from excited bending levels

The photodissociation dynamics of N2O in the wavelength region of 203-205 nm was studied by velocity map ion imaging. A speed resolution of 0.8% was obtained using standard projection imaging and subpixel centroiding calculations. To investigate N2O dissociation starting from the excited bending levels in the ground electronic state, a supersonic molecular beam and an effusive beam were used. The photoabsorption transition probability from the first excited bending level in the wavelength region of 203-205 nm was estimated to be seven times greater than that from the ground vibrational level.     

Rapid high-performance liquid chromatographic assay for the simultaneous analysis of non-steroidal anti-inflammatory drugs in plasma

A high-performance liquid chromatographic assay has been developed for the determination of a number of non-steroidal anti-inflammatory drugs in plasma. The samples were prepared by adding acetonitrile and perchloric acid to 200 microliter of plasma. Diclofenac, fenoprofen, ketoprofen, naproxen, phenylbutazone, piroxicam and sulindac were quantified in the supernatant produced using a mobile phase of phosphoric acid 0.03% (pH 2.5)-acetonitrile and a detecting wavelength of 254 nm. The reproducibility, linearity, precision and specificity of the assay were determined and found to be satisfactory. Alteration of the detection wavelength to 229 nm also permitted accurate determination of ibuprofen concentration in plasma. While reduction of the organic solvent content of the mobile phase and alteration of wavelength to 313 nm produced a system capable of quantifying salicylate and its metabolites in plasma and by further reducing the detecting wavelength to 237 nm, aspirin also was quantifiable. These methods have been applied in a cross-sectional study of medication compliance among rheumatoid arthritis patients treated with non-steroidal anti-inflammatory drugs.     

Enhancements in laser ablation inductively coupled plasma-atomic emission spectrometry based on laser properties and ambient environment

Analytical performance of laser ablation inductively coupled plasma-atomic emission spectrometry (ICP-AES) depends critically on the interaction between the laser light and the sample. The analyte emission line intensity in ICP-AES depends on the quantity of mass ablated. The effect of laser parameters (wavelength, pulse duration, and power density) was investigated for increasing the quantity of ablated mass. For fixed laser beam energy, the ablated mass can change 2 to 3 orders of magnitude by changing the laser beam spot size on the sample. The ablated mass quantity also depends on laser pulse duration and wavelength; and on ambient gas in the sample chamber. The shorter the pulse duration and wavelength, the higher the quantity of ablated mass. By using He in the chamber, the amount of mass increases by a factor of 2 for 30 ns excimer laser ablation and by an order of magnitude for ps-laser ablation.     

Inter-pulse delay optimization in dual-pulse laser induced breakdown vacuum ultraviolet spectroscopy of a steel sample in ambient gases at low pressure

Time-integrated spatially-resolved Laser Induced Breakdown Spectroscopy (LIBS) has been used to investigate spectral emissions from laser-induced plasmas generated on steel targets. Instead of detecting spectral lines in the visible/near ultraviolet (UV), as investigated in conventional LIBS, this work explored the use of spectral lines emitted by ions in the shorter wavelength vacuum ultraviolet (VUV) spectral region. Single-pulse (SP) and dual-pulse LIBS (DP-LIBS) experiments were performed on standardized steel samples. In the case of the double-pulse scheme, two synchronized lasers were used, an ablation laser (200 mJ/15 ns), and a reheating laser (665 mJ/6 ns) in a collinear beam geometry. Spatially resolved and temporally integrated laser induced plasma VUV emission in the DP scheme and its dependence on inter-pulse delay time were studied. The VUV spectral line intensities were found to be enhanced in the DP mode and were significantly affected by the inter-pulse delay time. Additionally, the influence of ambient conditions was investigated by employing low pressure nitrogen, argon or helium as buffer gases in the ablation chamber. The results clearly demonstrate the existence of a sharp ubiquitous emission intensity peak at 100 ns and a wider peak, in the multi-microsecond range of inter-pulse time delay, dependent on the ambient gas conditions.     

A Prototype of a Volumetric Three-Dimensional Display Based on Programmable Photo-Activated Phosphorescence

A proof-of-principle prototype of a volumetric 3D-displaying system is demonstrated by utilizing the photo-activated phosphorescence of two long-lived phosphorescent metal-porphyrins in dimethyl sulfoxide (DMSO), a photochemically deoxygenating solvent. The first phosphorescent sensitizer, Pt(TPBP), absorbs a light beam with a wavelength of 635 nm, and the sensitized singlet oxygen is scavenged by DMSO. The second phosphorescent emitter, Pt(OEP), absorbs a light beam with a wavelength of 532 nm and visibly phosphoresces only in the deoxygenated zone generated by the first sensitizer. The phosphorescent voxels, 3D images, and animations are well-defined by the intersections of the 635-nm and 532-nm light beams that are programmable by tuning of the excitation-power densities, the beam shapes, and the kinetics. As a pivotal selection rule for the phosphorescent molecular couple used in this 3D-displaying system, their absorptions and emissions must be orthogonal to each other, so that they can be excited and addressed independently.