2015年化学学科发展专题论坛(续)世纪之交的分析科学——回顾与思考

本文对分析科学某些方面近年来取得的进展及其发展趋势作了综述。     

Characterization of electrode surface roughness and its impact on ion trap mass analysis

With the recent trend towards mass spectrometer miniaturization, the fabrication of mass analyzers and other ion optical components is being performed at scales where critical dimensions range from several millimeters to several micrometers. Depending on the sizes of the objects and the nature of the fabrication method used, electrode surface roughness can become non‐negligible and affect the analytical performance of the mass analyzer. In this work, a method of characterizing surface roughness is introduced through the concept of spatial roughness frequency. The roughness of a given surface is quantitatively described using spatial roughness components at a series of frequencies and with characteristic intensities. Based on this concept, an analytical method has been developed to describe the electromagnetic field inside an electrode assembly including consideration for the electrode roughness. The methodology is applied in simplified form to cylindrical and rectilinear ion trap analyzers. Four types of surface finishes were applied to ion trap electrodes of various sizes to illustrate the surface roughness effects on the high‐order fields and to compare the analytical performance of the ion traps. Application of this method to arrays of large numbers of micro‐scale ion traps has enabled the impact of fabrication methodology to be evaluated in terms of mass resolution for the ion trap arrays. Copyright © 2008 John Wiley & Sons, Ltd.     

Blue‐green light generation using high brilliance edge emitting diode lasers

A review about second harmonic generation using edge emitting diode lasers and nonlinear crystals to obtain laser radiation in the blue‐green spectral range is presented. Therefore, pump laser radiation with high brightness and narrow bandwidth is necessary. Thus, this review gives an overview of the advances made with distributed feedback and Bragg reflector lasers, tapered lasers and amplifiers as well as external cavity diode lasers and master oscillator power amplifier schemes to achieve high brilliance emission. Since periodically poled materials have enabled high second harmonic conversion efficiencies with low and moderate pump powers, the review is focused on frequency doubling using those materials. The most commonly used materials, their properties and limitations are discussed briefly. Single pass and resonant SHG setups with waveguide and bulk nonlinear crystals are discussed and an emphasis on building compact and integrated devices is made.     

新型小型化的平面左手介质微带线及其后向波特性验证

基于裂缝谐振环结构的降频技术,首先设计了一种电尺寸较小的左手介质微带线单元,并根据电磁波在微带线上的传输和反射数据,分别计算了左手介质的有效介电常数和有效磁导率.之后针对左手介质八元阵列进行三维电磁仿真实验,结果表明该八元阵列在左手介质频段上具有独特的后向波效应,从而证实了该左手介质频段的存在.与传统的左手介质微带单元相比,阐述的左手介质单元的电尺寸减小了60%,而且结构简单,便于加工,适用于平面电路器件的小型化等应用研究工作. 关键词： 左手介质 小型化 双负特性 后向波特性     

小孔径微通道板

从空间分辨能力、时间分辨能力和动态范围方面介绍了通道小型化发展的趋势,根据微通道板性能和结构的关系分析了这种小型化带来的微通道板变形、破裂、结构错位等生产难题和解决方法.分析表明:美国MCP的孔径发展依次是12 μm,10 μm,9 μm,8 μm,6 μm和5 μm,先进国家微通道板孔径已经能够做到4 μm～5 μm,夜视仪的分辨能力已超过100 lp/mm;通道直径降至5 μm、4 μm甚至更低,通过改进材料成分和拉丝、排丝、压屏、酸溶工艺及设备可以实现5 μm以下小通道微通道板的制造.     

Single bead parallel synthesis and screening

Microstructured silicon wafers were employed as miniaturized solid-phase reaction vessels as well as miniaturized micro titer plates. Employing piezoelectric drop-on-demand liquid jets, a combinatorial library of 256 Peptides was synthesized on single beads. The synthesis protocol was associated to the location in the silicon nano-well arrangement. Products were photolytically cleaved in the same well that was used for synthesis and subsequently interrogated for thrombin inhibition in a homogeneous competition assay. The assay procedure was based on drop-on-demand liquid delivery and laser induced fluorescence imaging. The novel format proved useful for the integration of both synthesis and screening into one platform, a prerequisite for an iterative, evolutionary approach towards drug discovery.     

Miniaturized system of a gas chromatograph coupled with a Paul ion trap mass spectrometer

Miniature gas chromatography (GC) and miniature mass spectrometry (MS) instrumentation has been developed to identify and quantify the chemical compounds present in complex mixtures of gases. The design approach utilizes micro-GC components coupled with a Paul quadrupole ion trap (QIT) mass spectrometer. Inherent to the system are high sensitivity, good dynamic range, good QIT resolution, low GC flow-rates to minimize vacuum requirements and the need for consumables; and the use of a modular approach to adapt to volatile organic compounds dissolved in water or present in sediment. Measurements are reported on system response to gaseous species at concentrations varying over four orders of magnitude. The ability of the system to deal with complicated mixtures is demonstrated, and future improvements are discussed. The GC/QIT system described herein has a mass, volume and power that are, conservatively, one-twentieth of those of commercial off-the-shelf systems. Potential applications are to spacecraft cabin-air monitoring, robotic planetary exploration and trace-species detection for residual gas analysis and environmental monitoring.     

微等离子体发射光谱技术的研究进展

微等离子体是被限制在一个有限空间范围内的等离子体,其作为一种新型激发源具有能耗低、体积小、价格低等优点,在发射光谱仪器的微型化发展中展现了巨大的应用潜力。该文介绍了近年来基于微等离子体激发源构建的发射光谱(OES)系统在分析化学领域中的新应用。目前,微等离子体OES系统不仅能够直接测定气相或液体中的分析物,还可与气相色谱(GC)、化学蒸气发生(CVG)、电热蒸发(ETV)、微电渗析(μED)、毛细管电泳(CE)等多种技术联用,极大地扩展了该系统的应用范围。而提高微等离子体本身的激发能力,选择合适的进样方式,有望使微等离子体OES系统的性能得到进一步的提升。同时,相关仪器设备的开发将为痕量元素的现场分析提供可靠的手段。     

巧用注射器和Y型管改进铜与浓硫酸反应的实验

对现行教材及文献中铜与浓硫酸反应实验设计的优点和不足进行了分析,并在借鉴已有研究的基础上,秉承绿色化和微型化的实验设计理念,对该实验装置进行优化改进。通过利用一次性注射器和Y型管,使得整个实验过程在封闭系统中进行,实验现象明显的同时减少了药品用量,简化了操作步骤,尾气吸收彻底。     

一款小型化可见光两档7.5×变焦系统的设计

许多应用都期望以大视场搜索定位目标,以小视场瞄准跟踪目标.提出并设计一款小型化两档7.5×变焦距成像系统,其工作于486 nm～656 nm的可见光波段,短焦视场为±15°,长焦视场为±2°,两视场下F数均为2.8,系统总长仅为60 mm.系统由玻璃镜片及注塑镜片混合组成,包含一个前固定组和一个可动组,通过可动组在2个...