Name: visualization of ambient mass spectrometry with the use of schlieren photography
Uploaded: 2016-06-20T15:00:00.000+00:00
Duration: 6 min 49 s
Description: Watch this Scientific Journal Video about Visualization of Ambient Mass Spectrometry with the Use of Schlieren Photography at JoVE.com

The authors would like to acknowledge Caitlin Kowalewski for aiding in the editing and formatting of this publication.

1.纹影摄影<ol><li> 试验区的建立 注:测试区域存在直接在反射镜的前面。 <ol><li>夹紧在环形架夹子足够大以支撑反射镜的球面凹面镜（直径150毫米焦距1500毫米）。装上环架夹子用镜子一环站在垂直于地板。目前的研究中使用的3脚环支架，但任何高度可以，只要它是足够高，以便能够居中镜在源的观察窗中。 </li><li>放置环支架和反射镜到质谱仪的源的一侧。使平行于反射镜的面，并在同一高度，作为源。 </li><li>因此，其中心与质谱仪的中心源极区对准的镜子的位置。会发生仪器的一些重叠。 </li></ol></li><li> 截止，相机和光源 <ol><li> 隔断 <ol><li>连接金属板到三脚架的顶端。该板将作为一个平台，以保持两者的刀片和光源。剃刀刀片充当所谓的在纹影摄影的"截止"。 </li><li>附加刀片使用的磁体，使得锋利的边缘是垂直的金属板。 </li><li>放置在与镜像线的三脚架在反射镜3000毫米焦距的两倍。对齐刀片正交从反射镜反射的光的路径。 </li><li>手动调整三脚架的高度，以使刀片的锋利边缘大致与反射镜的中心对齐。 注:微调将在以后发生。 </li></ol></li><li> 相机 <ol><li>挂载数码相机300毫米长焦镜头在一个单独的三脚架。 </li><li>所以镜头（全变焦时）直接4厘米后面，并在同一平定位相机GHT作为刀片。此时不要取下镜头盖。 </li></ol></li><li> 选购的显示器 <ol><li>摄像机的视频输出连接到电脑显示器或电视机方便地查看实时的条纹现象。 注意:这是建议的过程。这个过程可以根据所用相机的类型而改变。 </li></ol></li><li> 针孔光源 <ol><li>钻一个小孔（约0.6毫米直径）为一个盖的中心（在此情况下，一个瓶盖使用了手电筒的直径相同），其可连接/贴在光源。确保该罩具有足够的直径以完全覆盖手电筒透镜。 </li><li>将盖子装在一个200流明使用铝箔胶带LED手电筒。 注:手电筒将得到温暖和建议高温胶带。 </li></ol></li><li> 光源定位 <ol><li>首先用一拉丝氨酸指针对准光源与反射镜，刀片和照相机，以确保光源的适当定位。 </li><li>放在旁边的刀片的金属板的激光指针。 </li><li>所以该光束射到反射镜的中心手动移动激光指针。根据需要进行调整，以确保使束的大约一半被阻塞反射光束垂直相交的剃刀刀片。 </li><li>手动调节后视镜的位置，激光指示器的光束直接在刀片瞄准如果光束对准不是在1.2.5.3实现。 小心！不要直视激光指针或反射光束。 </li><li>确保激光束被集中在透镜上，同时保持摄像机的镜头盖。 </li><li>而一切都对准与覆盖手电筒更换激光指针。确保该手电筒是在相同的方向的激光指针。 </li><li>打开手电筒和，用一张白纸，在截止观察的反射光。确保该光束是在截止的小的聚焦光斑。 </li><li>使任何垂直调整必要阻止大约一半的反射光束与截止的。 </li><li>在相机上取下镜头盖并专注于镜子。 注:建议相机/透镜在手动对焦模式中使用。 </li></ol></li></ol></li></ol> 2.示例测试对象:质谱电离源<ol><li>手动对齐测试区域内的质谱离子源，具有该喷嘴的端部和质谱仪的入口之间10mm的距离。 </li><li>手动打开针阀到环境源允许氮气通过源流动。 </li><li>打开用于控制质谱仪的软件。在这项研究中，所使用的软件是"SQ驱动程序"。点击网络连接然后勒-open-选择适当的调谐文件。 </li><li>一旦手动调谐打开应用所有电压和温度的环境源。每个质谱仪都将拥有自己的这一步软件。对于目前的研究，一旦手动调谐处于打开状态，点击按钮"电源电压为关"和按钮"所有的气体和加热器关闭"来执行此任务。 </li><li>观察排出用数码相机随着温度的增加的观点屏幕上的纹影装置的喷嘴的流动的外观。观察气流（见"结果"部分中描述）现身喷嘴的结束。该气体流可以在摄像机的背面看的，或者它可以直接在液晶监视器上观看。 </li><li>由任一记录来自摄像机的视频，或者服用所述气体流的图片收集图像，一旦所希望的图像被相机实时可视化。 </li><li>传送所收集的图像（多个）到计算机与CAMER存储卡或USB连接，并查看图像与您选择的软件。 </li></ol>从采集到的图像喷雾半角3.测定<ol><li>打开使用图像浏览软件采集到的图像并打印出采集到的图像（S）。 </li><li>绘制限定平行的气流的中心轴流动的用尺子的方向上的印刷图像（多个）上的线。 </li><li>绘制沿着用尺子打印的图像（多个）上的可视化气流的边缘的线。这可能由于微光存在于视频格式被可视化从记录的视频更好;用它来帮助识别打印图像的边缘。标记气流的外边缘以获得用于喷雾半角的范围内。 </li><li>测量中心轴和用量角器在3.2绘制的线之间产生的角度。 </li></ol>

<ol>
	<li>Settles, G. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Schlieren and Shadowgraph Techniques: Visualization Phenomena in Transparent Media. , (2001).</li><li>Strawa, A. W., Chapman, G. T., Arnold, J. O., Canning, T. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ballistic+range+and+aerothermodynamic+testing.">Ballistic range and aerothermodynamic testing.</a> J. Aircraft. 28 (7), 443-449 (1991).</li><li>Settles, G. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+gas+leaks+by+using+schlieren+optics.">Imaging gas leaks by using schlieren optics.</a> Pipeline &amp; Gas Journal. 226 (9), 28-30 (1999).</li><li>Takagi, T., Kubota, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+application+of+schlieren+optics+for+detection+of+protein+bands+and+other+phenomena+in+polyacrylamide+gel+electrophoresis.">The application of schlieren optics for detection of protein bands and other phenomena in polyacrylamide gel electrophoresis.</a> Electrophoresis. 11 (5), 361-366 (1990).</li><li>Clark, I. G., Cruz, J. R., Huges, M. F., Ware, J. S., Madlangbayan, A., Braun, R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aerodynamic+and+Aeroelastic+Characteristics+of+a+Tension+Cone+Inflatable+Aerodynamic+Decelerator.">Aerodynamic and Aeroelastic Characteristics of a Tension Cone Inflatable Aerodynamic Decelerator.</a> , (2009).</li><li>Froome, K. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Refractive+Indices+of+Water+Vapour,+Air,+Oxygen,+Nitrogen+and+Argon+at+72+kMc/s.">The Refractive Indices of Water Vapour, Air, Oxygen, Nitrogen and Argon at 72 kMc/s.</a> Proc. Phys. Soc. B. 68, 833-835 (1955).</li><li>Winter, G. T., Wilhide, J. A., LaCourse, W. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+a+Direct+Sample+Analysis+(DSA)+Ambient+Ionization.">Characterization of a Direct Sample Analysis (DSA) Ambient Ionization.</a> J. Am. Soc. Mass Spectrom. 26 (9), 1502-1507 (2015).</li><li>Pfeuffer, K. P., Schaper, J. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Halo-Shaped+Flowing+Atmospheric+Pressure+Afterglow:+A+Heavenly+Design+for+Simplified+Sample+Introduction+and+Improved+Ionization+in+Ambient+Mass+Spectrometry.">Halo-Shaped Flowing Atmospheric Pressure Afterglow: A Heavenly Design for Simplified Sample Introduction and Improved Ionization in Ambient Mass Spectrometry.</a> Anal. Chem. , 7512-7518 (2013).</li><li>Pfeuffer, K. P., Shelley, J. T., Ray, S. J., Hieftje, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualization+of+Mass+Transport+and+Heat+Transfer+in+the+FAPA+Ambient+Ionization+Source.">Visualization of Mass Transport and Heat Transfer in the FAPA Ambient Ionization Source.</a> J. Anal. At. Spectrom. 28 (379-387), 379-387 (2013).</li><li>Pfeuffer, K. P., Ray, S. J., Hieftje, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+and+Visualization+of+Mass+Transport+for+the+Flowing+Atmospheric+Pressure+Afterglow+(FAPA)+Ambient+Mass-Spectrometry+Source.">Measurement and Visualization of Mass Transport for the Flowing Atmospheric Pressure Afterglow (FAPA) Ambient Mass-Spectrometry Source.</a> J. Am. Soc. Mass Spectrom. 25 (5), 800-808 (2014).</li><li>Keelor, J. D., Dwivedi, P., Fern&#225;ndez, F. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+Effective+Approach+for+Coupling+Direct+Analysis+in+Real+Time+with+Atmospheric+Pressure+Drift+Tube+Ion+Mobility+Spectrometry.">An Effective Approach for Coupling Direct Analysis in Real Time with Atmospheric Pressure Drift Tube Ion Mobility Spectrometry.</a> J. Am. Soc. Mass Spectrom. 25 (9), 1538-1548 (2014).</li></ol>

There are no competing financial interests with this article.

有几方面的考虑，必须之前尝试该协议来解决。除了围绕质谱仪的源和反射镜的空间，足够的开放空间必须可用于容纳所述反射镜的焦点的两倍的距离。此外，反射镜的大小由正在研究源的尺寸最终决定。如果反射镜是太小，源将不被充分显示。要注意的是一些，如果不是全部，源盖必须被除去以实现纹影摄影成像技术是重要的。 实际设置中最关键的步骤是纹影装置的各部分的取向。镜子必须垂直于地面，刀片必须在镜子的焦距长度的两倍正好放置。在这个距离，反射光将被聚焦到一个小点。封锁的剃刀刀片的光量也是我mportant。如果差图像产生的，在第一方面中，调整将与刀片的位置。当刀片不阻挡足够的光到达照相机的，没有对比形成，因此该气体将不可见。如果太多的光被阻挡的图像出现黑暗，从而难以区分从物体所研究的氮气流的更细微的信息。 该技术的一个限制是，必须有在后台的折射率和研究领域的术语一个大的差异。这将取决于所讨论的实验室的温度和湿度。室温氮是通常很难看到作为背景空气是由约78％的氮。这是在所描述的设置，因为氮的温度从其导致的折射率的变化的来源而变化克服。 总体而言，T的显著贡献他的协议是了解参与到源中电离的物理过程的能力。反过来，这将允许用户更好地调整仪器代替盲目地变化的参数，以及作为用于优化的条件下提供的推理。该技术的优点是能够使用所有的信息从物理和化学过程，以获得更好的灵敏度和选择性随环境电离源6。用户可以利用纹影图像，以确定所述源的物理性质，而质谱数据可以用来理解源的化学性质。 未来的应用将是此技术适用于任一其他各种环境电离在市场上可用的源，或一个非商业装置。这也可以应用到利用气体流的任何其它乐器/机器。

质谱法，可用于分子质量鉴定的分析工具，已经成为最强大的分析技术的最新之一。在过去的十年新的环境电离源的整个主机已经成为可用的质谱检测。用于本手稿收集的数据，直接样品分析（DSA）源被利用。虽然这些来源是非常灵活的，需要用于其优化和目的的延长的物理电离过程的更详细的了解。该实验的目的是通过使用一种称为纹影摄影技术的设备上的氮气流的可视化的环境源中，以便更好地理解电离过程。 科学研究往往通过观察，这是困难的，如果研究的对象是透明的，肉眼启动。条纹照相是一种技术，可以让无形通过依靠透明介质1内的折射率变化变得可见。的折射率的不均匀性引起的光允许可视化的歪曲。纹影技术已经在各种专业领域，包括弹道学建模，航天工程，一般气体检测和流量监测，并且有时被常规地用于显现蛋白质条带在凝胶电泳2-5。 大多数环境电离源，以促进电离使用气体流。广泛范围的条件下可以存在为源的选择，然而该实验的参数必须涉及的气体与从周围实验室空气不同的折射率的利用率。这种特殊的研究利用热氮气。应该指出，只有在折射率的差小，从气流和空气纯氮之间观察到在RT 6，主要是因为IR主要是氮组成。此问题是在这种情况下，由于其产生的折射率显著足以改变为要观察的气体的气流中的纯氮气的高温克服。 其他质谱来源，如大气解吸化学电离（DAPCI）7，实时（DART）流动气压余辉（FAPA）8-10，并直接分析11电离源使用了条纹摄影。此协议的目的是讨论如何使用基本条纹照相配置学习环境电离。这种技术，然而，也适用于任何数量的涉及气流不同的分析技术。

<table><tbody><tr><td>Flashlight</td><td>EAGTAC</td><td>D25A Ti</td><td>or equivalent&amp;nbsp;</td></tr><tr><td>Spherical Concave Mirror</td><td>Anchor Optics</td><td>27633</td><td></td></tr><tr><td>Rebel EOS T2i</td><td>Canon</td><td>4462B001</td><td>or equivalent&amp;nbsp;</td></tr><tr><td>300 mm telephoto lens</td><td>Canon</td><td>6473A003</td><td>or equivalent&amp;nbsp;</td></tr><tr><td>Direct Sample Analysis (DSA) Ionization Source</td><td>PerkinElmer</td><td>MZ300560</td><td>or equivalent&amp;nbsp;</td></tr><tr><td>Sq 300 MS with SQ Driver Software</td><td>PerkinElmer</td><td>N2910801</td><td>or equivalent&amp;nbsp;</td></tr><tr><td>Ring Stand</td><td>Fisher Scientific</td><td>11-474-207</td><td>or equivalent&amp;nbsp;</td></tr><tr><td>Laser Pointer</td><td>Apollo</td><td>MP1200</td><td>or equivalent&amp;nbsp;</td></tr><tr><td>razor blade</td><td>Blue Hawk</td><td>34112</td><td>or equivalent&amp;nbsp;</td></tr><tr><td>small drill bit #73</td><td>CML Supply</td><td>503-273</td><td>or equivalent&amp;nbsp;</td></tr><tr><td>Protractor</td><td>Sterling&amp;nbsp;</td><td>582</td><td>or equivalent&amp;nbsp;</td></tr><tr><td>Hose Clamp</td><td>Trident</td><td>720-6000L</td><td>or equivalent&amp;nbsp;</td></tr></tbody></table>

visualization of ambient mass spectrometry with the use of schlieren photography

这份手稿概述了如何使用条纹照相可视化质谱环境电离源。为了正确地优化质谱仪，有必要表征和理解源的物理原理。大多数商业环境电离源利用氮气，氦气，或大气空气的射流，以促进分析物的电离。因此，纹影摄影可用于通过利用​​在所述流和环境空气用于实时可视化之间的折射率的差异来可视化气流。基本设置需要一个摄像头，镜子，手电筒，和刀片。如果配置正确，源的实时图像通过观察它的反射观察。这允许洞察在源的作用机制，以及通路到它的优化可以得到阐明。光棚上的不可见的情况。

纹影设置包括质谱电离源的示意图在图1中。当所有的纹影部件正确对齐可以发现，在测试区域内的气体可以被看作是对比明暗区域。 图2示出了这种对比如何能用于观察如何从质谱源变化的氮气喷流的形状喷嘴尺寸减小。 源和气流的完整，未裁剪纹影图像可在图3中找到。该图像示出了测试的取向对象相对于反射镜。 图3中的图像还示出了当适量，约50％，光被所述刀片切断什么应该预计。如果截止要么是过高（ 图4），或过低（ 图5 </STRONG&gt;），图像不佳将导致。 一旦设置完成，可以一边看自己的摄像机的视频屏幕上的效果调整各种质谱仪参数。这个图像，沿着质谱仪的实际信号，允许将迅速达到由于气体流的新的理解最佳条件。 然后这些图像可以被用来计算氮气流的喷射一半的角度。喷雾半角告诉用户的氮气流的整体尺寸。这个角度是由喷嘴，以及该气体的压力和温度的直径进行。 图6是半角测量以恒定的喷嘴的尺寸和在气体压力变化的表示。正如所料，半角度的增加的压力相应地增加，表示该气体的整体尺寸增加流。 图7是与恒压半角的表示，同时改变喷嘴直径。正如所料，半角度与增加喷嘴直径增大。这意味着在氮气喷射出来的源作为喷嘴直径的尺寸的总体比例增加增加。 <img alt="图1" src="/files/ftp_upload/54195/54195fig1.jpg" /> 图1.条纹示意图（重新打印与参考7权限）。与质谱离子源的条纹照相设备的示意图。 <a href="https://www.jove.com/files/ftp_upload/54195/54195fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图2" src="/files/ftp_upload/54195/54195fig2.jpg" /> 图2.尼特可视化<html>罗根流（再打印与来自参考7许可）从与（A）4.8毫米，（B）。3.2毫米，（C）的 1.5毫米，（D）的 0.5的不同喷嘴的内径电离源气体流量。纹影照片毫米。 <a href="https://www.jove.com/files/ftp_upload/54195/54195fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图3" src="/files/ftp_upload/54195/54195fig3.jpg" /> 图3.环境资源的可视化，与截止正确定位电离源的广角纹影照片。 <a href="https://www.jove.com/files/ftp_upload/54195/54195fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <html> g4.jpg"/&gt; 图4.可视化与低截止差。纹影照片与定位过低截止。 <a href="https://www.jove.com/files/ftp_upload/54195/54195fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图5" src="/files/ftp_upload/54195/54195fig5.jpg" /> 图5.可怜的可视化与高截止。纹影照片与定位过高截止。 <a href="https://www.jove.com/files/ftp_upload/54195/54195fig5large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图6" src="/files/ftp_upload/54195/54195fig6.jpg" /> 图6.半角与瓦斯压力，一个图表，描述在与不同的气体压力恒定的喷嘴尺寸喷雾半角的变化。="htt​​ps://www.jove.com/files/ftp_upload/54195/54195fig6large.jpg"目标="_空白"&gt;点击此处查看该图的放大版本。 <img alt="图7" src="/files/ftp_upload/54195/54195fig7.jpg" /> 图7.半角VS喷嘴尺寸，一个图表，描述在与不同的喷嘴尺寸定压喷射半角的变化。 <a href="https://www.jove.com/files/ftp_upload/54195/54195fig7large.jpg" target="_blank">请点击此处查看该图的放大版本。</a>

Watch this Scientific Journal Video about Visualization of Ambient Mass Spectrometry with the Use of Schlieren Photography at JoVE.com

Visualization of Ambient Mass Spectrometry with the Use of Schlieren Photography

This paper presents a protocol for the visualization of gaseous streams of an ambient ionization source using schlieren photography and mass spectrometry.

环境质谱可视化纹影摄影的使用

This manuscript outlines how to visualize mass spectrometry ambient ionization sources using schlieren photography. In order to properly optimize the mass ...

visualization-ambient-mass-spectrometry-with-use-schlieren

Nanyang Technological University

Research

JoVE Journal

Chemistry

8.3K 次观看.  University of Maryland, Baltimore County. This paper presents a protocol for the visualization of gaseous streams of an ambient ionization source using schlieren photography and mass spectrometry.

视频: Visualization of Ambient Mass Spectrometry with the Use of Schlieren Photography

Molecular Beam Mass Spectrometry With Tunable Vacuum Ultraviolet (VUV) Synchrotron Radiation

Tunable soft ionization coupled to mass spectroscopy is a powerful method to investigate isolated molecules, complexes and clusters and their spectroscopy and dynamics1-4. Fundamental studies of photoionization processes of biomolecules provide information about the electronic structure of these systems. Furthermore determinations of ionization energies and other properties of biomolecules in the gas phase are not trivial, and these experiments provide a platform to generate these data. We have developed a thermal vaporization technique coupled with supersonic molecular beams that provides a gentle way to transport these species into the gas phase. Judicious combination of source gas and temperature allows for formation of dimers and higher clusters of the DNA bases. The focus of this particular work is on the effects of non-covalent interactions, i.e., hydrogen bonding, stacking, and electrostatic interactions, on the ionization energies and proton transfer of individual biomolecules, their complexes and upon micro-hydration by water1, 5-9.
We have performed experimental and theoretical characterization of the photoionization dynamics of gas-phase uracil and 1,3-dimethyluracil dimers using molecular beams coupled with synchrotron radiation at the Chemical Dynamics Beamline10 located at the Advanced Light Source and the experimental details are visualized here. This allowed us to observe the proton transfer in 1,3-dimethyluracil dimers, a system with pi stacking geometry and with no hydrogen bonds1. Molecular beams provide a very convenient and efficient way to isolate the sample of interest from environmental perturbations which in return allows accurate comparison with electronic structure calculations11, 12. By tuning the photon energy from the synchrotron, a photoionization efficiency (PIE) curve can be plotted which informs us about the cationic electronic states. These values can then be compared to theoretical models and calculations and in turn, explain in detail the electronic structure and dynamics of the investigated species 1, 3.

Molecular Beam Mass Spectrometry With Tunable Vacuum Ultraviolet VUV Synchrotron Radiation

A molecular beam coupled to tunable vacuum ultraviolet photoionization mass spectrometer at a synchrotron provides a convenient tool to explore the electronic structure of isolated gas phase molecules and clusters. Proton transfer mechanisms in DNA base dimers were elucidated with this technique.

可调式真空紫外（VUV）同步辐射分子束质谱分析

Tunable soft ionization coupled to mass spectroscopy is a powerful method to investigate isolated molecules, complexes and clusters and their spectroscopy ...

科研

工程学

An Inverse Analysis Approach to the Characterization of Chemical Transport in Paints

The ability to directly characterize chemical transport and interactions that occur within a material (i.e., subsurface dynamics) is a vital component in understanding contaminant mass transport and the ability to decontaminate materials. If a material is contaminated, over time, the transport of highly toxic chemicals (such as chemical warfare agent species) out of the material can result in vapor exposure or transfer to the skin, which can result in percutaneous exposure to personnel who interact with the material. Due to the high toxicity of chemical warfare agents, the release of trace chemical quantities is of significant concern. Mapping subsurface concentration distribution and transport characteristics of absorbed agents enables exposure hazards to be assessed in untested conditions. Furthermore, these tools can be used to characterize subsurface reaction dynamics to ultimately design improved decontaminants or decontamination procedures. To achieve this goal, an inverse analysis mass transport modeling approach was developed that utilizes time-resolved mass spectroscopy measurements of vapor emission from contaminated paint coatings as the input parameter for calculation of subsurface concentration profiles. Details are provided on sample preparation, including contaminant and material handling, the application of mass spectrometry for the measurement of emitted contaminant vapor, and the implementation of inverse analysis using a physics-based diffusion model to determine transport properties of live chemical warfare agents including distilled mustard (HD) and the nerve agent VX.

In this paper, a procedure for quantifying the mass transport parameters of chemicals in various materials is presented. This process involves employing an inverse-analysis based diffusion model to vapor emission profiles recorded by real-time, mass spectrometry in high vacuum.

一个反分析方法化工运输的油漆表征

The ability to directly characterize chemical transport and interactions that occur within a material (i.e., subsurface dynamics) is a vital component in ...

化学

Whole-body Mass Spectrometry Imaging by Infrared Matrix-assisted Laser Desorption Electrospray Ionization (IR-MALDESI)

Ambient ionization sources for mass spectrometry (MS) have been the subject of much interest in the past decade. Matrix-assisted laser desorption electrospray ionization (MALDESI) is an example of such methods, where features of matrix-assisted laser desorption/ionization (MALDI) (e.g., pulsed nature of desorption) and electrospray ionization (ESI) (e.g., soft-ionization) are combined. One of the major advantages of MALDESI is its inherent versatility. In MALDESI experiments, an ultraviolet (UV) or infrared (IR) laser can be used to resonantly excite an endogenous or exogenous matrix. The choice of matrix is not analyte dependent, and depends solely on the laser wavelength used for excitation. In IR-MALDESI experiments, a thin layer of ice is deposited on the sample surface as an energy-absorbing matrix. The IR-MALDESI source geometry has been optimized using statistical design of experiments (DOE) for analysis of liquid samples as well as biological tissue specimens. Furthermore, a robust IR-MALDESI imaging source has been developed, where a tunable mid-IR laser is synchronized with a computer controlled XY translational stage and a high resolving power mass spectrometer. A custom graphical user interface (GUI) allows user selection of the repetition rate of the laser, number of shots per voxel, step-size of the sample stage, and the delay between the desorption and scan events for the source. IR-MALDESI has been used in variety of applications such as forensic analysis of fibers and dyes and MSI of biological tissue sections. Distribution of different analytes ranging from endogenous metabolites to exogenous xenobiotics within tissue sections can be measured and quantified using this technique. The protocol presented in this manuscript describes major steps necessary for IR-MALDESI MSI of whole-body tissue sections.

Whole-body Mass Spectrometry Imaging by Infrared Matrix-assisted Laser Desorption Electrospray Ionization IR-MALDESI

A mass spectrometry imaging (MSI) source operated at atmospheric pressure was developed by coupling mid-infrared laser desorption and electrospray post-ionization. Exogenous ice matrix was used as the energy-absorbing matrix to facilitate resonant desorption of tissue-related material. This manuscript provides a step-by-step protocol for performing IR-MALDESI MSI of whole-body neonatal mouse.

全身质谱成像红外基质辅助激光解吸电喷雾电离（IR-MALDESI）

Ambient ionization sources for mass spectrometry (MS) have been the subject of much interest in the past decade. Matrix-assisted laser desorption ...

生物工程

Mass-Sensitive Particle Tracking to Characterize Membrane-Associated Macromolecule Dynamics

Short-lived or transient interactions of macromolecules at and with lipid membranes, an interface where a multitude of essential biological reactions take place, are inherently difficult to assess with standard biophysical methods. The introduction of mass-sensitive particle tracking (MSPT) constitutes an important step toward a thorough quantitative characterization of such processes. Technically, this was made possible through the advent of interferometric scattering microscopy (iSCAT)-based mass photometry (MP). When the background removal strategy is optimized to reveal the two-dimensional motion of membrane-associated particles, this technique allows the real-time analysis of both diffusion and molecular mass of unlabeled macromolecules on biological membranes. Here, a detailed protocol to perform and analyze mass-sensitive particle tracking of membrane-associated systems is described. Measurements performed on a commercial mass photometer achieve time resolution in the millisecond regime and, depending on the MP system, a mass detection limit down to 50 kDa. To showcase the potential of MSPT for the in-depth analysis of membrane-catalyzed macromolecule dynamics in general, results obtained for exemplary protein systems such as the native membrane interactor annexin V are presented.

This protocol describes an iSCAT-based image processing and single-particle tracking approach that enables the simultaneous investigation of the molecular mass and the diffusive behavior of macromolecules interacting with lipid membranes. Step-by-step instructions for sample preparation, mass-to-contrast conversion, movie acquisition, and post-processing are provided alongside directions to prevent potential pitfalls.

质量敏感颗粒跟踪，用于表征膜相关的高分子动力学

Short-lived or transient interactions of macromolecules at and with lipid membranes, an interface where a multitude of essential biological reactions take ...

生物化学

Atmospheric-pressure Molecular Imaging of Biological Tissues and Biofilms by LAESI Mass Spectrometry

Ambient ionization methods in mass spectrometry allow analytical investigations to be performed directly on a tissue or biofilm under native-like experimental conditions. Laser ablation electrospray ionization (LAESI) is one such development and is particularly well-suited for the investigation of water-containing specimens. LAESI utilizes a mid-infrared laser beam (2.94 &mu;m wavelength) to excite the water molecules of the sample. When the ablation fluence threshold is exceeded, the sample material is expelled in the form of particulate matter and these projectiles travel to tens of millimeters above the sample surface. In LAESI, this ablation plume is intercepted by highly charged droplets to capture a fraction of the ejected sample material and convert its chemical constituents into gas-phase ions. A mass spectrometer equipped with an atmospheric-pressure ion source interface is employed to analyze and record the composition of the released ions originating from the probed area (pixel) of the sample. A systematic interrogation over an array of pixels opens a way for molecular imaging in the microprobe analysis mode. A unique aspect of LAESI mass spectrometric imaging is depth profiling that, in combination with lateral imaging, enables three-dimensional (3D) molecular imaging. With current lateral and depth resolutions of ~100 &mu;m and ~40 &mu;m, respectively, LAESI mass spectrometric imaging helps to explore the molecular structure of biological tissues. Herein, we review the major elements of a LAESI system and provide guidelines for a successful imaging experiment.

Laser ablation electrospray ionization (LAESI) is an atmospheric-pressure ion source for mass spectrometry. In the imaging mode, a mid-infrared laser probes the distributions of molecules across a tissue section or a biofilm. This technique presents a new approach for diverse bioanalytical studies carried out under native experimental conditions.

常压LAESI质谱生物组织和生物膜的分子成像

Ambient ionization methods in mass spectrometry allow analytical investigations to be performed directly on a tissue or biofilm under native-like ...

生物学

Direct Analysis of Single Cells by Mass Spectrometry at Atmospheric Pressure

Analysis of biochemicals in single cells is important for understanding cell metabolism, cell cycle, adaptation, disease states, etc. Even the same cell types exhibit heterogeneous biochemical makeup depending on their physiological conditions and interactions with the environment. Conventional methods of mass spectrometry (MS) used for the analysis of biomolecules in single cells rely on extensive sample preparation. Removing the cells from their natural environment and extensive sample processing could lead to changes in the cellular composition. Ambient ionization methods enable the analysis of samples in their native environment and without extensive sample preparation.1 The techniques based on the mid infrared (mid-IR) laser ablation of biological materials at 2.94 &mu;m wavelength utilize the sudden excitation of water that results in phase explosion.2 Ambient ionization techniques based on mid-IR laser radiation, such as laser ablation electrospray ionization (LAESI) and atmospheric pressure infrared matrix-assisted laser desorption ionization (AP IR-MALDI), have successfully demonstrated the ability to directly analyze water-rich tissues and biofluids at atmospheric pressure.3-11 In LAESI the mid-IR laser ablation plume that mostly consists of neutral particulate matter from the sample coalesces with highly charged electrospray droplets to produce ions. Recently, mid-IR ablation of single cells was performed by delivering the mid-IR radiation through an etched fiber. The plume generated from this ablation was postionized by an electrospray enabling the analysis of diverse metabolites in single cells by LAESI-MS.12 This article describes the detailed protocol for single cell analysis using LAESI-MS. The presented video demonstrates the analysis of a single epidermal cell from the skin of an Allium cepa bulb. The schematic of the system is shown in Figure 1. A representative example of single cell ablation and a LAESI mass spectrum from the cell are provided in Figure 2.

Single cell analysis is performed by mass spectrometry on plant and animal cells at atmospheric pressure by using a sharpened optical fiber to sample the cells for laser ablation electrospray ionization (LAESI) mass spectrometry.

在大气压力质谱直接分析单细胞

Analysis of biochemicals in single cells is important for understanding cell metabolism, cell cycle, adaptation, disease states, etc. Even the same cell ...

使用 VSFG 显微镜进行多模式、快速、高光谱化学分析

Multimodal Nonlinear Hyperspectral Chemical Imaging Using Line-Scanning Vibrational Sum-Frequency Generation Microscopy

Vibrational sum-frequency generation (VSFG), a second-order nonlinear optical signal, has traditionally been used to study molecules at interfaces as a spectroscopy technique with a spatial resolution of ~100 &#181;m. However, the spectroscopy is not sensitive to the heterogeneity of a sample. To study mesoscopically heterogeneous samples, we, along with others, pushed the resolution limit of VSFG spectroscopy down to ~1 &#181;m level and constructed the VSFG microscope. This imaging technique not only can resolve sample morphologies through imaging, but also record a broadband VSFG spectrum at every pixel of the images. Being a second-order nonlinear optical technique, its selection rule enables the visualization of non-centrosymmetric or chiral self-assembled structures commonly found in biology, materials science, and bioengineering, among others. In this article, the audience will be guided through an inverted transmission design that allows for imaging unfixed samples. This work also showcases that VSFG microscopy can resolve chemical-specific geometric information of individual self-assembled sheets by combining it with a neural network function solver. Lastly, the images obtained under brightfield, SHG, and VSFG configurations of various samples briefly discuss the unique information revealed by VSFG imaging.

作者聚焦:揭示 VSFG 显微镜在研究介观异质自组装结构中的潜力 

A multimodal, rapid hyperspectral imaging framework was developed to obtain broadband vibrational sum-frequency generation (VSFG) images, along with brightfield, second harmonic generation (SHG) imaging modalities. Due to the infrared frequency being resonant with molecular vibrations, microscopic structural and mesoscopic morphology knowledge is revealed of symmetry-allowed samples.

基于线扫描振动和频生成显微镜的多模态非线性高光谱化学成像

Vibrational sum-frequency generation (VSFG), a second-order nonlinear optical signal, has traditionally been used to study molecules at interfaces as a ...

Applications of the Single-probe: Mass Spectrometry Imaging and Single Cell Analysis under Ambient Conditions

Mass spectrometry imaging (MSI) and in-situ single cell mass spectrometry (SCMS) analysis under ambient conditions are two emerging fields with great potential for the detailed mass spectrometry (MS) analysis of biomolecules from biological samples. The single-probe, a miniaturized device with integrated sampling and ionization capabilities, is capable of performing both ambient MSI and in-situ SCMS analysis. For ambient MSI, the single-probe uses surface micro-extraction to continually conduct MS analysis of the sample, and this technique allows the creation of MS images with high spatial resolution (8.5 &#181;m) from biological samples such as mouse brain and kidney sections. Ambient MSI has the advantage that little to no sample preparation is needed before the analysis, which reduces the amount of potential artifacts present in data acquisition and allows a more representative analysis of the sample to be acquired. For in-situ SCMS, the single-probe tip can be directly inserted into live eukaryotic cells such as HeLa cells, due to the small sampling tip size (&lt; 10 &#181;m), and this technique is capable of detecting a wide range of metabolites inside individual cells at near real-time. SCMS enables a greater sensitivity and accuracy of chemical information to be acquired at the single cell level, which could improve our understanding of biological processes at a more fundamental level than previously possible. The single-probe device can be potentially coupled with a variety of mass spectrometers for broad ranges of MSI and SCMS studies.

Here, we present protocols to perform both ambient mass spectrometry imaging (MSI) of tissues and in-situ live single cell MS (SCMS) analysis using the single-probe, which is a miniaturized multifunctional device for MS analysis.

单探头的应用:根据环境条件质谱成像和单细胞分析

Mass spectrometry imaging (MSI) and in-situ single cell mass spectrometry (SCMS) analysis under ambient conditions are two emerging fields with great ...

环境质谱可视化纹影摄影的使用

摘要

探索更多视频

此视频中的章节

可调式真空紫外（VUV）同步辐射分子束质谱分析

一个反分析方法化工运输的油漆表征

全身质谱成像红外基质辅助激光解吸电喷雾电离（IR-MALDESI）

质量敏感颗粒跟踪，用于表征膜相关的高分子动力学

常压LAESI质谱生物组织和生物膜的分子成像

在大气压力质谱直接分析单细胞

基于线扫描振动和频生成显微镜的多模态非线性高光谱化学成像

基于线扫描振动和频生成显微镜的多模态非线性高光谱化学成像

基于线扫描振动和频生成显微镜的多模态非线性高光谱化学成像

单探头的应用:根据环境条件质谱成像和单细胞分析