光纤光谱仪的多样化组装及应用——介绍一个仪器分析实验

介绍了一个本科生的仪器分析实验——光纤光谱仪的多样化组装及应用。利用光源、光纤和电荷耦合器件检测器等部件,组装出紫外-可见光谱仪、分子荧光光谱仪、近红外光谱仪、拉曼光谱仪和激光诱导荧光光谱仪。通过本实验,不仅能够拓展传统光学实验的内容,而且可以通过自己动手组装仪器,培养学生的专业实践能力和知识应用能力。     

基于显微共聚焦拉曼技术对三种食源性致病菌的快速鉴别研究

采用显微共聚焦拉曼技术,建立了对三种常见食源性致病菌快速鉴别的检测方法。使用XploRA PLUS共聚焦拉曼光谱仪,在激光功率为5 mW、积分时间为30s、积分次数为1次的条件下,对德尔卑沙门氏菌、副溶血性弧菌和金黄色葡萄球菌进行了拉曼光谱数据的采集。对拉曼光谱采用多项式平滑算法和荧光背底扣除后,采用主成分分析法(PCA)对预处理后的数据进行降维,提取出前三个主成分的累计方差贡献率达到了95.4％,样本明显的聚为了3类。同时结合Fisher判别分析法(FLD)构建分类模型,对三种样本进行交叉验证,分类准确率达到了100％。结果表明,采用显微共聚焦拉曼技术与PCA-FLD方法结合可实现对三种食源性致病菌的快速准确鉴别且模型检测精度高,方法具有一定的实用性及参考价值。     

显微激光拉曼光谱法鉴别红色签字笔种类的研究

目前,字迹的书写时间的鉴定已成为法庭科学中亟待解决的热点问题.区分书写材料的种类是其中关键的一个步骤.分析方法主要有紫外可见分光光度法、漫反射傅立叶变换红外光谱法[1]、薄层色谱法[2]、气相色谱法[3]、液相色谱法[4]、毛细管电泳法[5]、拉曼光谱法等.显微激光拉曼光谱技术是一种较新的、可靠的检测技术,可非破坏性进行物质鉴定、分子结构分析等方面的研究.目前,发达国家已将该项技术应用于法庭科学中.但有关激光拉曼光谱研究笔迹书写材料鉴定的文献并不多见[6],对于红色签字笔的研究更是鲜有报道,本研究利用激光拉曼光谱仪对红色签字笔字迹进行无损检验,为鉴别红色墨水材料提供了科学依据.     

快速检测三聚氰胺激光仪问世

中国检验检疫科学研究院2月28日宣布,该院利用激光拉曼技术,自主研发了用于现场快速检测三聚氰胺的激光拉曼光谱仪以及配套试剂。使用该仪器和配套试剂,能定量检测出液态奶中高于5×10-7(0.5ppm)的三聚氰胺,每个样品检测仅需半分钟。中国检科院首席专家、研究员邹明强说,牛奶不同于其它食品,原料奶的保质期为4h,如果奶农把原料奶送到实验室来检测三聚氰胺等物质,时间长了牛奶很容易变坏,因此需要研发小型、低成本、准确的现场快速检测设备。中国检科院结合纳米和激光技术,利用激光拉曼仪,成功开发了现场快速检测液态奶中三聚氰胺含量的技术以及配套增敏试剂,可使传统的拉曼检测灵敏度大幅提高,克服了样品基质干扰,真正实现了快速、准确地分析实验样品中的三聚氰胺。据悉,目前报道的国外同类技术对牛奶样品检测,加上样品处理,共需要50min,且不能达到对三聚氰胺的定量检测。(仪器信息网)快速检测三聚氰胺激光仪问世     

基于显微拉曼光谱的金刚石非晶层厚度检测方法

提出了利用激光共聚焦显微拉曼光谱仪测试非晶层厚度的方法。以单晶区与非晶区的拉曼峰值比值为研究对象,研究发现此值与非晶层厚度具有较好的相关性。方法为非晶层测量提供了一种快速、无损、廉价的定量检测途径。实验证明,对于厚度小于50 nm的非晶层,方法检测误差小于1.5 nm。     

大型仪器科学管理(192~195)超分辨荧光共聚焦显微技术进展、自主创新研发和开放共享使用现状

简要梳理了超分辨荧光共聚焦显微成像技术的发展历史.在此基础上, 重点总结了中国自主创新高分辨荧光共聚焦显微成像技术取得的突破, 特别是2006年以来, 中国科学院和北京大学成功研发了几款较为成熟的超分辨荧光共聚焦显微系统, 有力地推动了中国自主创新仪器研制的进展.最后, 在大型仪器设备开放共享评价考核数据分析的基础上, 着重分析了高校和科研院所激光共聚焦显微镜的开放共享使用情况.     

国产拉曼光谱取得重大突破 可用于地沟油检测

“地沟油自此有了国产克星,国产仪器检测成本将大幅降低”清华大学材料所所长翁端兴奋地说。不久前,由江苏省经信委和江苏省科技厅组织的来自清华大学、沈阳工业大学、中国计量科学研究院等单位的数十名行业专家齐聚一堂,召开拉曼光谱仪国产化鉴定会,专家全票通过认可了我国江阴极光仪器科技有限公司自主研制的拉曼光谱仪。这为打破拉曼光谱仪的欧洲技术垄断,加速国产化铺平了道路。     

激光拉曼光谱法测定流体包裹体压力的研究进展

介绍了目前测试流体包裹体压力的方法并指出其中存在的问题,综述了激光拉曼光谱法测试流体包裹体压力的研究进展。与目前的测试方法相比,激光拉曼光谱法具有快速、方便的特点,但激光拉曼光谱分析结果主要受到样品、荧光、出峰信号弱等因素的影响,使得该技术在微区微观分析研究上存在局限性。随着仪器和方法的不断改进,流体包裹体拉曼光谱分析技术将会成为一种方便、准确的地质压力测量手段(引用文献34篇)。     

激光共焦显微拉曼光谱技术对手印中海洛因及其稀释剂的检测研究

利用激光共焦显微拉曼光谱技术对汗潜手印和油潜手印中的海洛因、烟酰胺、碳酸钠、葡萄糖、淀粉、蔗糖、滑石粉进行了检测,并对主要拉曼特征峰所对应的分子振动基团进行了识别,在此基础上,对手印中的混合毒品进行分析检测。实验结果表明,在不破坏手印的情况下,激光共焦显微拉曼光谱技术实现了对手印中海洛因、烟酰胺、碳酸钠、葡萄糖、淀粉、蔗糖、滑石粉的快速检测,对手印中混合毒品样品中的海洛因成分能够有效的识别,手印中的油脂不影响以上各物质的检测识别,通过显微红外光谱技术对试验结果的准确性进行了确认,研究结果将为相关涉毒案件的侦破提供有力的技术支持。     

激光功率和积分时间对表面增强拉曼光谱的影响EI北大核心CSCD

表面增强拉曼光谱(SERS)技术能够有效增强低浓度样品的拉曼光谱强度,然而由于SERS的结构、材质等工艺原因,SERS实际应用中往往由于未能正确选择激光功率与积分时间而导致测量效果显著下降。本文以浓度为2,0.08μg/mL的三聚氰胺溶液样品、Au@Ag NPs纳米柱结构固态SERS基底为例,使用自主搭建的便携式拉曼光谱仪,采集不同激光功率和积分时间下的SERS光谱,使用算法平滑光谱、计算光谱基线,得到样品SERS光谱强度和SERS光谱基线强度变化趋势。实验表明,激发光源功率和积分时间改变时,SERS光谱基线强度在不同光谱区域变化幅度不同,部分光谱区域基线强度的变化幅度远大于样品光谱强度,导致使用拉曼光谱仪进行光谱测量时极易造成光谱强度饱和,影响低浓度样品的测量。临时更换样品试剂或SERS基底又会增加成本,且操作繁琐。研究发现,通过控制激光功率和积分时间这2个简单可控的变量,可以在一定程度上抑制SERS光谱基线、提高样品光谱强度,从而避免因光谱强度易饱和而无法测得低浓度样品光谱信号的问题。     

A compact collinear AOTF Raman spectrometer

A compact, lightweight, completely packaged, uncooled, fully-automated collinear acousto-optic tunable-filter (AOTF) based spectrometer has been used to measure Raman spectra of three organic energetic materials (NQ, HMX, and TNT) using argon-ion laser excitation. Even though the resolution of the AOTF spectrometer is modest (7.4 cm(-1)) and it was not specifically designed for measuring Raman spectra, it has performed impressively. Such an instrument is specially useful for remote sensing and field measurements. In this paper, we will describe this instrument, present the measured Raman spectra and their comparison with the corresponding FT-IR spectra.     

Application of portable Raman instruments for fast and non-destructive detection of minerals on outcrops

Raman spectral signatures have been obtained in situ for a series of minerals using portable Raman instruments. Cerussite, anglesite, wulfenite, titanite, calcite, tremolite, andradite and quartz were detected using portable Raman spectrometer First Defender XL (Ahura). Baryte, almandine and realgar Raman spectra obtained by this instrument in the field were compared to the data measured by the other mobile Raman instrument Inspector Raman (DeltaNu). Bench Raman dispersive microspectrometer (InVia Reflex, Renishaw) was used for comparative purposes. All spectra were obtained using a 785nm diode excitation. Although displaying lower spectral resolution comparing with the laboratory confocal instrument both portable instruments permit unambiguous detection of minerals in the field. These possibilities designate portable Raman machines as excellent tools for field geological applications. Miniaturised Raman instrument combined with LIBS will be included in the payload of the EXO Mars mission and would open interesting research possibilities in other in situ field planetary studies.     

Raman efficiencies of natural rocks and minerals: performance of a remote Raman system for planetary exploration at a distance of 10 meters

Raman spectroscopy is a powerful technique for materials analysis, and we are developing and analyzing a remote Raman system for use on a planetary lander or rover. We have acquired data at a distance of 10m from a variety of geologic materials using different instrument designs. We have employed a pulsed laser with both an ungated detector and a gated detector. A gated detector can reduce long-lived fluorescence while still collecting all Raman signal. In order to design a flight instrument, we need to quantify how natural surfaces will respond to laser stimulus. We define remote Raman efficiency of natural surfaces as the ratio of radiant exitance leaving a natural surface to the irradiance of the incident laser. The radiant exitance of a natural surface is the product of the sample radiance, the projected solid angle, and the full-width-half-maximum of the Raman signal. We have determined the remote Raman efficiency for a variety of rocks and minerals. The best efficiencies are achieved for large, clear, single crystals that produce the most radiant exitance, while darker fine-grained mineral mixtures produce lower efficiencies. By implementing a pulsed laser, gated detector system we have improved the signal detection and have generally decreased the integration time necessary to detect Raman signal from natural surfaces.     

Combined Raman spectrometer/laser-induced breakdown spectrometer for the next ESA mission to Mars

Among the different instruments that have been pre-selected to be on-board the Pasteur payload on ExoMars is the Raman/laser induced breakdown spectroscopy (LIBS) instrument. Raman spectroscopy and LIBS will be integrated into a single instrument sharing many hardware commonalities. An international team under the lead of TNO has been gathered to produce a design concept for a combined Raman spectrometer/LIBS elegant bread-board (EBB). The instrument is based on a specially designed, extremely compact, spectrometer with high resolution over a large wavelength range, suitable for both Raman spectroscopy and LIBS measurements. Low mass, size and power consumption are the main drivers of the instrument's design concept. In this paper, science objectives for the combined instrument are detailed. Background information on Raman spectroscopy and LIBS are presented, focussing on the synergy of these two techniques. In the last section, the instrument concept resulting from the assessment of the feasibility of the combined Raman/LIBS EBB is presented.     

便携式三聚氰胺快速检测仪的研制与应用

自主研发了便携式三聚氰胺速检仪,利用纳米增敏表面增强拉曼光谱法,定量检出限为0.5 mg/kg;采用相对测量方式可有效克服测量不稳定性.用于原奶、消毒奶、酸奶、奶粉中三聚氰胺检测,线性关系良好.样品前处理步骤简单.通常情况,平均单样检测时间小于2 min,仪器检测时间小于30 s,尤其适用于现场快速分析.除了可应用于乳...     

用于电化学界面研究的共焦显微拉曼光谱技术(英文)

系统地介绍了将共焦显微拉曼光谱系统用于电化学界面研究的方法 ,包括铂电极的粗糙和电化学拉曼电解池的设计 .进行了铂上氢、氧和氯共吸附的拉曼光谱研究 .通过对甲醇氧化过程的现场跟踪 ,提出检测界面区溶液浓度变化和计算溶液 pH值的方法 .实验表明拉曼光谱技术可作为研究实际应用体系的重要工具 .     

Development of a Fiber Optic Probe to Measure NIR Raman Spectra of Cervical Tissue In Vivo

The goal of this study was to develop a compact fiber optic probe to measure near infrared Raman spectra of human cervical tissue in vivo for the clinical diagnosis of cervical precancers. A Raman spectrometer and fiber optic probe were designed, constructed and tested. The probe was first tested using standards with known Raman spectra, and then the probe was used to acquire Raman spectra from normal and precancerous cervical tissue in vivo. Raman spectra of cervical tissue could be acquired in vivo in 90 s using incident powers comparable to the threshold limit values for laser exposure of the skin. Although some silica signal obscured tissue Raman bands below 900 cm^-1, Raman features from cervical tissue could clearly be discerned with an acceptable signal-to-noise ratio above 900 cm^-1. The success of the Raman probe described here indicates that near infrared Raman spectra can be measured in vivo from cervical tissues. Increasing the power of the excitation source could reduce the integration time to below 20 s.     

Novel multichannel plasma-source mass spectrometer

A novel mass spectrometer system for elemental analysis is described. The instrument combines an inductively coupled plasma (ICP) ion source with a Mattauch-Herzog mass spectrometer and multichannel ion detector. Ion detection is simultaneous and an elemental mass spectrum (20–230 μ) can be acquired in <10 ms. The instrument can be used with either Ar or He plasma sources. The speed of the system makes it well suited for acquisition of fast (10–100-ms duration) transient signals, such as those generated by pulsed laser ablation sample introduction. Preliminary system performance characteristics, which include detection limits, stability, and measurement accuracy, obtained with an Ar ICP are presented. The application of the instrument to the analysis of solid samples by laser ablation is discussed.     

宽离子能量检测范围垂直引入反射式飞行时间质谱仪的研制

本实验室研制了国内首台宽离子能量检测范围飞行时间质谱仪。仪器采用紧凑式电子轰击源设计,配合离子透镜系统有效的调制离子流,飞行时间质量分析器采用了离子垂直引入式,双场加速和双场反射以及大尺寸MCP检测装置设计。仪器单离子信号半峰宽约2 ns,仪器分辨率优于1600FWHM,检测实际样品质量范围为1~127 amu(仪器理论质量检测上限优于800 amu),可检测离子能量范围优于2个数量级(3~140 eV)。若该TOF质量分析器与短瞬高压脉冲放电离子源耦合联用,可广泛应用于高能离子束的快速检测,如真空阴极放电对制备薄膜、离子注入材料的表征,导电材料的离子电荷态分布以及离子扩散速度的测定等。     

Rapid detection of an anthrax biomarker by surface-enhanced Raman spectroscopy

A rapid detection protocol suitable for use by first-responders to detect anthrax spores using a low-cost, battery-powered, portable Raman spectrometer has been developed. Bacillus subtilis spores, harmless simulants for Bacillus anthracis, were studied using surface-enhanced Raman spectroscopy (SERS) on silver film over nanosphere (AgFON) substrates. Calcium dipicolinate (CaDPA), a biomarker for bacillus spores, was efficiently extracted by sonication in nitric acid and rapidly detected by SERS. AgFON surfaces optimized for 750 nm laser excitation have been fabricated and characterized by UV-vis diffuse reflectance spectroscopy and SERS. The SERS signal from extracted CaDPA was measured over the spore concentration range of 10(-14)-10(-12) M to determine the saturation binding capacity of the AgFON surface and to calculate the adsorption constant (Kspore=1.7 x 10(13) M(-1)). At present, an 11 min procedure is capable of achieving a limit of detection (LOD) of approximately 2.6 x 10(3) spores, below the anthrax infectious dose of 10(4) spores. The data presented herein also demonstrate that the shelf life of prefabricated AgFON substrates can be as long as 40 days prior to use. Finally, these sensing capabilities have been successfully transitioned from a laboratory spectrometer to a field-portable instrument. Using this technology, 10(4) bacillus spores were detected with a 5 s data acquisition period on a 1 month old AgFON substrate. The speed and sensitivity of this SERS sensor indicate that this technology can be used as a viable option for the field analysis of potentially harmful environmental samples.