JS is indebted to Prof. B. Hoge of the Inorganic Chemistry department, Bielefeld University, for the idea of establishing the presented inlet system. The analyzed phosphane was a generous gift from Prof. B. Hoge. Sample preparation of the analyzed compound was performed by M. Wiesemann. Photographs of the phospane were taken by Dr. J. Bader. The mechanical workshop of the faculty of chemistry is acknowledged for the manufacturing of the interface and the glass workshop of the faculty of chemistry for the manufacturing of the lockable test tubes with flanges. Prof. B. Hoge and Prof. H. Gr&#246;ger are acknowledged for funding of this publication.

1，样品制备<ol><li>使用定制的可锁定的试管有凸缘（ 图1），用于运输和样品转移到质谱仪。之前填充样品，疏散附着到多个歧管的Schlenk线的可锁定的试管，通过加热用热枪除去残留的水。泄试管用干燥氩气，并再次抽空，同时加热。 </li><li>沉浸在上锁的试管成冷阱充满液氮（注意:用液氮时要小心）。浓缩样品到从连接到的Schlenk线的歧管的样品容器的试管中，收在试管的顶部锁定以及歧管，并从氮浴中取出锁定试管。作为质谱分析是非常敏感的，有少量就足够了。大多数分析物会在分析过程中保留在可锁定试管和是可用于进一步的实验在测量后。 </li></ol><img alt="图1" fo:content-width="5in" src="/files/ftp_upload/51858/51858fig1highres.jpg" width="500" /> 图用于样品转移1上锁的试管。 A）的法兰用于连接到冷进入系统中，试管（B）的特氟隆抽头，以使化合物的无空气的条件下运输，（C）的螺钉以操作特氟隆抽头。 2，测量质谱<ol><li>根据质谱仪（这里的制造商提供的说明来样测量，调整和校准质谱仪之前，一个高分辨磁质谱AutoSpec X（真空发生器，现在Waters公司，英国曼彻斯特）被使用。使用perflourokerosene（PFK）作为一个标准，调整质谱仪约2800 米处）的分辨率/ Z 119，10％峰谷定义。删除推从离子源的直接入口的杆和安装在试管的外接口（ 图2）。为了防止推杆头的加热，设置在入口的方法来在质谱仪中的控制软件"隔膜"。 </li><li>连接的可锁定的试管填充有样品到外接口的凸缘。打开外接口的针形阀和疏散口。抽真空后，小心地打开球阀，以离子源以完成抽真空步骤。关闭外接口的针形阀。注意:在测试管的特氟隆抽头具有在此步骤被关闭。 </li><li>在质谱仪中的软件开始质量测量。具有闭合针阀，打开试管的特氟隆抽头简略，使分析物的气相分子进入接口的外部部分。再次关闭铁氟龙水龙头。 注:该接口与TEFL之间的空间的外部部分一起关于抽头和可锁定的试管的凸缘（比较图1和图2B）作为分析过程中分析物的气体贮存器。 </li><li>同时观察离子源的真空测量仪小心打开针阀。这个步骤允许被分析物分子进入质谱仪的离子源。真空不应该在测量过程中下降到低于10 -5毫巴。 注:根据质量好的分析物的质谱的波动是在大约10 -6毫巴获得。该样品的质谱现在被记录。通常，试样量泄漏到仪器通过针阀足以记录质谱数分钟。的情况下的离子的强度降低，打开针阀多一点允许更多的采集时间。如果结果为70电子伏特的质谱的质量不令人满意，质谱可使用的低动能被记录电子， 例如 ，20伏特。 </li></ol><img alt="图2" fo:content-width="5in" src="/files/ftp_upload/51858/51858fig2highres.jpg" width="500" /> 图2冷进气系统与嵌合的VG高分辨磁质谱AutoSpec十甲离子源空上锁试管）可锁定的试管中，（B）的试管之间的法兰连接的冷进入系统，（C）的针形阀，（D）的不锈钢板与密封件作为连接到所述离子源中，直接入口（E）的界面中，推杆的陶瓷前端是可见的。 3，测量后<ol><li>关闭外接口的针形阀。关闭球阀至离子源。停止采集质谱中的软件。 </li><li>疏散进气系统而完全打开针阀。发泄球时的界面阀和针阀关闭。再次抽空界面，在该步骤中，以除去残留的样品的蒸气在界面打开针阀。重复此步骤，至少3倍。 </li><li>删除接口可锁定试管。继续进行下一个样品或来自离子源的凸缘移除外接口，它与推杆取代。 </li></ol>

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The authors have nothing to disclose.

从在标准样品制备程序，分解的化合物收购质谱载于本协议。所提出的技术被设计为金属organyls，硅烷和膦，这是很容易受到氧化和/或水解的分析，使得它有趣特别是对于无机化学家。为了达到最佳的效果，真空或空气的条件下在整个分析加以保存。因此该协议应认真遵守。的情况下，分析物进入与空气接触泄漏或错误处理的进口系统的，因为，造成严重后果如样品容器的爆炸可根据化合物的情况下进行分析（ 图4）。样品制备也应该只执行通过用于与的Schlenk线工作的，因为它们可以爆受过训练的人员由于不良的制造玻璃器皿真空下时。爆炸米飞行可以通过与空气因处理不当反应性化合物，在进入的Schlenk线的接触而引起的。液态氧的危险，在惰性气体中杂质冻结在寒冷的陷阱，也应考虑。液体氧的任何（上）有机化合物的接触可能导致引起的Schlenk线的爆炸剧烈反应。在分析过程中，在质谱仪的离子源中的压力应仔细观察，如在离子源的高压力可能会损坏仪器。 与挥发性金属organyls，极易受到氧化和/或水解硅烷和膦很少或根本不可能使用先进设备，最先进的与ESI或MALDI离子源，如根据一般进行样品制备和电离质谱分析大气条件。这里，冷进入系统呈现为物导入现有的方法的一个有价值的扩展。然而，冷入口系统是不与ESI和MALDI离子源兼容，因为它呈现气态分析物的离子化源​​的流动，而ESI需要的分析物溶液和MALDI分析物共结晶与基质的离子的生成的流程图。因为每个电离策略，EI也有一个缺点 - 由于电子束的能量高，碎裂频繁发生。取决于分析物的性质可能会导致在没有分子离子。然而，分析物可以使用碎片离子进行识别，特别是当所提供的化合物是高纯度的。用于明确识别，合成路线在此情况下是已知的。对于化合物，其中的分子离子是存在于质谱中，该片段离子可用于证实该分子的结构。由于冷入口系统的设计中，所提出的策略是有限的，以化合物具有一定的波动。分析物的波动性要足够，一llow的化合物在真空下在液氮温度下的转移 - 要么通过沸腾或升华。化合物与太低蒸气压不会产生高质量的质谱。单个质量测量之间的串扰很少观察到，并且可以通过仔细地抽进系统被进一步最小化。 在一般情况下，测量可以与每一个质谱仪配备有EI离子源和直接进样系统中进行。所呈现的冷进入系统是运行在几秒钟内，并且需要在质谱仪上没有改变。然而，冷进入系统的接口具有可定制的，根据所使用的EI质谱的现有入口的尺寸。根据可用的质谱仪的功能，附加的实验，可以进行诸如用于判定或确认的元素组成或精确质量测量质量分析离子显象管抽动能源法（MIKES）的裂解途径的阐明。因此，冷进气系统代表了一个额外的进样口的战略旁边用推杆在EI质谱经常使用的直接入口。

化合物，如金属organyls，硅烷，或phosphanes通过质谱法的分析并不总是可行的。几个这些化合物是已知的时，分解迅速与空气接触。因此，测量的质谱时，最重要的步骤是样品制备中，分析物的转移到质谱仪和离子发生在不存在空气。在这个协议中，我们描述了一种策略，以满足这些要求，并提出了一个入口系统，这使得它能够得到挥发性化合物以前没有被进行质谱分析的质谱图，由于其难以处理和快速分解的环境条件下。由此，明确识别新的或现有的挥发性金属organyls，硅烷和phosphanes，易被氧化或水解的，现在可以与质谱的协助下进行的。有两个要求其具有为了分析化合物必须满足这易于氧化或水解:在惰性条件下的样品制备和离子产生。最后的前提下可使用质谱仪的离子源在真空下操作很容易地得到满足。这与大部分基质辅助激光解吸/电离（MALDI）质谱，并与所有的电子轰击离子源（EI）质谱仪1,2的情况。电喷雾电离（ESI）是不为易被氧化或水解的化合物的分析很容易兼容，如在电离过程需要在环境条件3下的地方。然而，对于一些化合物，它们与氧或水，干燥，并与该最ESI源操作雾化气体的反应不大力是通过质谱法4足够用于分析。这也是对于电离策略类似于ESI， 例如 ，低温ESI，低温大气压电离和低温液体二次离子质谱SPECTR的情况下ometry 5-7。与此相反，样品制备和转移到惰性条件下的离子源是更有挑战性。两个MALDI和ESI文书已加上手套箱中以使在惰性气氛中4,8易于氧化和/或水解的化合物的样品制备方法。质谱仪接口到手套箱中任一个传输毛细管（ESI）或直接连接到手套式操作箱（MALDI）。液体喷射场解吸/电离（LIFDI） - -与敏感化合物的分析报告9,10的手套箱中，以经由传输毛细管质谱仪的耦合也将使用另一种离子化的策略是可能的。 此外，MALDI和LIFDI不适合于高挥发性化合物的分析。 MALDI需要的共结晶的分析物与基质和LIFDI需要被分析物上的沉积中的EMITTER从一个解决方案。与两个离子化策略是非常可能的是，分析物将蒸发随着溶剂。在对比MALDI仪器，EI质谱仪通常提供了几种方法用于引入样品进入离子源:直接导入探针（少量的固体颗粒，油，或蜡沉积到其使用推杆引入铝坩埚中） ，隔片入口（液体），或耦合用气相色谱仪。再次，在至少部分样品转移发生在环境条件下是难以在惰性气氛下进行。 在20世纪60年代，进样系统，提出了使样品的引入真空成的EI仪器的离子源-全玻璃加热进气系统（AGHIS）11,12。这里，将样品位于密封件的玻璃毛细管，将其插入到AGHIS内。接着，AGHIS抽真空和与所述样品的玻璃容器破裂。该AGHIS随后，加热以蒸发其中通过的泄漏装置达到的EI质谱仪的离子源的样品。当制备在手套箱内用样品的玻璃毛细管中，样品可以被引入到质谱仪中，没有任何接触到空气。然而，AGHIS是它不是市售的，难以组装，即使是熟练的吹玻璃车间的设备。由于直接入口之间的大尺寸切换使用推杆和AGHIS不是直线前进。 在我们的质谱实验室，我们在AGHIS的风格开发出了类似的进气系统。然而，由于这是不可能的加热进口系统中，分析物具有表现出以进入质谱仪的离子源有一定的波动。分析物的挥发性必须足够，以允许化合物在真空下在液氮德转印温度 - 无论是煮沸或升华。该定制进气系统包括一个不锈钢板，其被定位在直接进样系统，不锈钢管与针型阀，和一个凸缘，以可连接含有样品可锁定试管。冷进样系统的安装无需修改质谱仪（高分辨磁质谱AutoSpec X，真空发生器，现在Waters公司，英国曼彻斯特） - 冷进气系统和直接入口之间使用，可以在几秒钟内轻松完成推杆切换。 所呈现的进口系统是特别有用的，当金属organyls，硅烷，或phosphanes，易被氧化或水解，必须进行分析。这些化合物被用核谱核磁共振（NMR）或红外（IR）光谱法常用分析。不幸的是，这些方法允许并不总是一个明确的鉴定的化合物，因为它们产生incompletE资料， 例如 ，当元件如氯或溴是该分子的一部分。另一方面气体电子衍射可以提供关于分析物的详细信息，但是，该方法是非常耗时的，样品的制备是困难的，并且只有少数群体能够进行这些分析13,14。这里，对于金属organyls，硅烷，或phosphanes，易被氧化或水解被EI质谱分析中的冷进气系统是有机化学家能够明确识别的新型化合物大量使用对（上）由与信息提供他们关于特征碎片离子的分子和质量。为质谱的一种物质对测量的唯一先决条件是在减压一定的波动性。

<table><tbody><tr><td>VG Autospec X</td><td>Micromass Co. UK Ltd (now Waters)</td><td></td><td>Other EI mass spectrometers with direct inlet using a push rod should also be compatible with this technique</td></tr><tr><td>Lockable test tubes with flange</td><td></td><td></td><td>Custom made, teflon tap should be used for locking the test tube</td></tr><tr><td>Interface for lockable test tubes</td><td></td><td></td><td>Custom made, interface is prepared from stainless steel. Needle valve has to be included into the interface-design!</td></tr><tr><td>Schlenk line</td><td></td><td></td><td>Custom made, has to include vacuum pump for evacuation of thest tubes and cold trap with liquid nitrogen for trapping of the sample</td></tr></tbody></table>

analysis of volatile and oxidation sensitive compounds using a cold inlet system and electron impact mass spectrometry

这部影片提出了一个协议，用电子轰击电离挥发和氧化敏感的化合物的质量spectrometrical分析。挥发和氧化敏感的化合物通过质谱法的分析是不容易实现的，因为国家的最先进的所有质谱方法所需要的分析物（电喷雾电离），共中的至少一种的样品制备步骤， 例如 ，溶解和稀释与基质化合物（基质辅助激光解吸/电离），或所制备的样品转移到质谱仪的电离源分析物-crystallization，大气压的条件下进行。这里，使用进样系统的描述使用扇区字段质谱仪配备有电子轰击电离源挥发性金属organyls，硅烷，和phosphanes的分析。所有的样品制备步骤和样品引入的离子源质谱仪发生或者下无空气条件下或在真空条件下，使化合物的分析非常容易被氧化。所提出的技术是为无机化学家兴趣尤其，与金属organyls，硅烷，或phosphanes，它必须使用在惰性条件，如的Schlenk技术进行处理工作。操作的原理，提出在该视频。

的三（三氟甲基）膦的EI质谱示于图3中 ，化合物，其分解时迅速与空气（ 图4）接触。所呈现的界面允许质谱对这些化合物的直线前进的测量。新颖界面的操作是容易和快速的和操作的质谱仪，当与常规应用于直接入口使用推杆并没有任何障碍。 <img alt="图3" fo:content-width="5in" src="/files/ftp_upload/51858/51858fig3highres.jpg" width="500" /> 图3的三质谱（三氟甲基）膦， <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/51858/51858fig3highres.jpg" target="_blank">请点击这里查看该图的放大版本。</a> <img alt="图4" fo:content宽度="5英寸"SRC ="/文件/ ftp_upload / 51858 / 51858fig4highres.jpg"WIDTH ="500"/&gt; 图4（A）贮存容器装满三（三氟甲基）膦。 （B）的容器填充有少量的三（三氟甲基）膦。 （C）在与空气接触，三（三氟甲基）膦点燃自发。 （照片礼貌J·贝德博士。）

Watch this Scientific Journal Video about Analysis of Volatile and Oxidation Sensitive Compounds Using a Cold Inlet System and Electron Impact Mass Spectrometry at JoVE.com

Analysis of Volatile and Oxidation Sensitive Compounds Using a Cold Inlet System and Electron Impact Mass Spectrometry

这部影片提出了一个协议，用电子轰击电离挥发和氧化敏感的化合物的质量spectrometrical分析。所提出的技术是为无机化学家兴趣尤其，与金属organyls，硅烷，或具有使用惰性条件下，例如在的Schlenk技术进行处理phosphanes工作。

挥发和氧化敏感的化合物使用冷进气系统和电子轰击质谱分析

This video presents a protocol for the mass spectrometrical analysis of volatile and oxidation sensitive compounds using electron impact ionization. The ...

analysis-volatile-oxidation-sensitive-compounds-using-cold-inlet

Nanyang Technological University

Research

JoVE Journal

Chemistry

9.6K 次观看.  Bielefeld University. 这部影片提出了一个协议，用电子轰击电离挥发和氧化敏感的化合物的质量spectrometrical分析。所提出的技术是为无机化学家兴趣尤其，与金属organyls，硅烷，或具有使用惰性条件下，例如在的Schlenk技术进行处理phosphanes工作。 

视频: Analysis of Volatile and Oxidation Sensitive Compounds Using a Cold Inlet System and Electron Impact Mass Spectrometry

Characterizing Bacterial Volatiles using Secondary Electrospray Ionization Mass Spectrometry (SESI-MS)

Secondary electrospray ionization mass spectrometry (SESI-MS) is a method developed for the rapid detection of volatile compounds, without the need for sample pretreatment. The method was first described by Fenn and colleagues1 and has been applied to the detection of illicit drugs2 and explosives3-4, the characterization of skin volatiles5, and the analysis of breath6-7.
SESI ionization occurs by proton transfer reactions between the electrospray solution and the volatile analyte, and is therefore suitable for the analysis of hetero-organic molecules, just as in traditional electrospray ionization (ESI). However, unlike standard ESI, the proton transfer process of SESI occurs in the vapor phase rather than in solution (Fig. 1), and therefore SESI is best suited for detecting organic volatiles and aerosols.
We are expanding the use of SESI-MS to the detection of bacterial volatiles as a method for bacterial identification and characterization8. We have demonstrated that SESI-MS volatile fingerprinting, combined with a statistical analysis method, can be used to differentiate bacterial genera, species, and mixed cultures in a variety of growth media.8 Here we provide the steps for obtaining bacterial volatile fingerprints using SESI-MS, including the instrumental parameters that should be optimized to ensure robust bacterial identification and characterization.

Characterizing Bacterial Volatiles using Secondary Electrospray Ionization Mass Spectrometry SESI-MS

Secondary electrospray ionization mass spectrometry (SESI-MS) enables the detection of volatile organic compounds (VOCs) without the need for any sample pretreatment. This protocol provides instructions for the rapid (within minutes) characterization of bacterial VOCs using SESI-MS.

使用辅助电喷雾质谱（SESI - MS）表征细菌挥发

Secondary electrospray ionization mass spectrometry (SESI-MS) is a method developed for the rapid detection of volatile compounds, without the need for ...

科研

生物工程

PTR-ToF-MS Coupled with an Automated Sampling System and Tailored Data Analysis for Food Studies: Bioprocess Monitoring, Screening and Nose-space Analysis

Proton Transfer Reaction (PTR), combined with a Time-of-Flight (ToF) Mass Spectrometer (MS) is an analytical approach based on chemical ionization that belongs to the Direct-Injection Mass Spectrometric (DIMS) technologies. These techniques allow the rapid determination of volatile organic compounds (VOCs), assuring high sensitivity and accuracy. In general, PTR-MS requires neither sample preparation nor sample destruction, allowing real time and non-invasive analysis of samples. PTR-MS are exploited in many fields, from environmental and atmospheric chemistry to medical and biological sciences. More recently, we developed a methodology based on coupling PTR-ToF-MS with an automated sampler and tailored data analysis tools, to increase the degree of automation and, consequently, to enhance the potential of the technique. This approach allowed us to monitor bioprocesses (e.g. enzymatic oxidation, alcoholic fermentation), to screen large sample sets (e.g. different origins, entire germoplasms) and to analyze several experimental modes (e.g. different concentrations of a given ingredient, different intensities of a specific technological parameter) in terms of VOC content. Here, we report the experimental protocols exemplifying different possible applications of our methodology: i.e. the detection of VOCs released during lactic acid fermentation of yogurt (on-line bioprocess monitoring), the monitoring of VOCs associated with different apple cultivars (large-scale screening), and the in vivo study of retronasal VOC release during coffee drinking (nosespace analysis).

Proton Transfer Reaction Time of Flight Mass Spectrometry allows high-sensitivity, rapid and non-invasive analysis of volatile organic compounds. To demonstrate its potential, we give three examples: lactic acid fermentation of yogurt (on-line bioprocess monitoring), different apple genotypes (large-scale screening), and retronasal space after drinking coffee (nosespace analysis).

PTR-ToF-MS结合自动采样系统和食品研究定制数据分析:生物过程监测，筛选和鼻空间分析

Proton Transfer Reaction (PTR), combined with a Time-of-Flight (ToF) Mass Spectrometer (MS) is an analytical approach based on chemical ionization that ...

化学

Extraction of Aqueous Metabolites from Cultured Adherent Cells for Metabolomic Analysis by Capillary Electrophoresis-Mass Spectrometry

Metabolomic analysis is a promising omics approach to not only understand the specific metabolic regulation in cancer cells compared to normal cells but also to identify biomarkers for early-stage cancer detection and prediction of chemotherapy response in cancer patients. Preparation of uniform samples for metabolomic analysis is a critical issue that remains to be addressed. Here, we present an easy and reliable protocol for extracting aqueous metabolites from cultured adherent cells for metabolomic analysis using capillary electrophoresis-mass spectrometry (CE-MS). Aqueous metabolites from cultured cells are analyzed by culturing and washing cells, treating cells with methanol, extracting metabolites, and removing proteins and macromolecules with spin columns for CE-MS analysis. Representative results using lung cancer cell lines treated with diamide, an oxidative reagent, illustrate the clearly observable metabolic shift of cells under oxidative stress. This article would be especially valuable to students and investigators involved in metabolomics research, who are new to harvesting metabolites from cell lines for analysis by CE-MS.

The purpose of this article is to describe a protocol for extraction of aqueous metabolites from cultured adherent cells for metabolomic analysis, particularly, capillary electrophoresis-mass spectrometry.

毛细管电泳质谱法提取培养细胞中的水代谢物进行代谢组学分析

Metabolomic analysis is a promising omics approach to not only understand the specific metabolic regulation in cancer cells compared to normal cells but ...

癌症研究

Fizzy Extraction of Volatile Organic Compounds Combined with Atmospheric Pressure Chemical Ionization Quadrupole Mass Spectrometry

Chemical analysis of volatile and semivolatile compounds dissolved in liquid samples can be challenging. The dissolved components need to be brought to the gas phase, and efficiently transferred to a detection system. Fizzy extraction takes advantage of the effervescence phenomenon. First, a carrier gas (here, carbon dioxide) is dissolved in the sample by applying overpressure and stirring the sample. Second, the sample chamber is decompressed abruptly. Decompression leads to the formation of numerous carrier gas bubbles in the sample liquid. These bubbles assist the release of the dissolved analyte species from the liquid to the gas phase. The released analytes are immediately transferred to the atmospheric pressure chemical ionization interface of a triple quadrupole mass spectrometer. The ionizable analyte species give rise to mass spectrometric signals in the time domain. Because the release of the analyte species occurs over short periods of time (a few seconds), the temporal signals have high amplitudes and high signal-to-noise ratios. The amplitudes and areas of the temporal peaks can then be correlated with concentrations of the analytes in the liquid samples subjected to fizzy extraction, which enables quantitative analysis. The advantages of fizzy extraction include: simplicity, speed, and limited use of chemicals (solvents).

Fizzy extraction is a new laboratory technique for analysis of volatile and semivolatile compounds. A carrier gas is dissolved in the liquid sample by applying overpressure and stirring the sample. The sample chamber is then decompressed. The analyte species are liberated to the gas phase due to effervescence.

挥发性有机化合物与大气压化学电离四极杆质谱联用

Chemical analysis of volatile and semivolatile compounds dissolved in liquid samples can be challenging. The dissolved components need to be brought to ...

Combustion Chemistry of Fuels: Quantitative Speciation Data Obtained from an Atmospheric High-temperature Flow Reactor with Coupled Molecular-beam Mass Spectrometer

This manuscript describes a high-temperature flow reactor experiment coupled to the powerful molecular beam mass spectrometry (MBMS) technique. This flexible tool offers a detailed observation of chemical gas-phase kinetics in reacting flows under well-controlled conditions. The vast range of operating conditions available in a laminar flow reactor enables access to extraordinary combustion applications that are typically not achievable by flame experiments. These include rich conditions at high temperatures relevant for gasification processes, the peroxy chemistry governing the low temperature oxidation regime or investigations of complex technical fuels. The presented setup allows measurements of quantitative speciation data for reaction model validation of combustion, gasification and pyrolysis processes, while enabling a systematic general understanding of the reaction chemistry. Validation of kinetic reaction models is generally performed by investigating combustion processes of pure compounds. The flow reactor has been enhanced to be suitable for technical fuels (e.g. multi-component mixtures like Jet A-1) to allow for phenomenological analysis of occurring combustion intermediates like soot precursors or pollutants. The controlled and comparable boundary conditions provided by the experimental design allow for predictions of pollutant formation tendencies. Cold reactants are fed premixed into the reactor that are highly diluted (in around 99 vol% in Ar) in order to suppress self-sustaining combustion reactions. The laminar flowing reactant mixture passes through a known temperature field, while the gas composition is determined at the reactors exhaust as a function of the oven temperature. The flow reactor is operated at atmospheric pressures with temperatures up to 1,800 K. The measurements themselves are performed by decreasing the temperature monotonically at a rate of -200 K/h. With the sensitive MBMS technique, detailed speciation data is acquired and quantified for almost all chemical species in the reactive process, including radical species.

An investigation of the oxidative combustion chemistry of novel biofuels, fuel components, or jet fuels by comparison of quantitative speciation data is presented. The data can be used for kinetic model validation and enables fuel assessment strategies.This manuscript describes the atmospheric high-temperature flow reactor and demonstrates its capabilities.

燃料燃烧化学: 用耦合分子束质谱仪从大气高温流反应器中获得的定量形态数据

This manuscript describes a high-temperature flow reactor experiment coupled to the powerful molecular beam mass spectrometry (MBMS) technique. This ...

Quantitative Analysis by Thermogravimetry-Mass Spectrum Analysis for Reactions with Evolved Gases

During energy conversion, material production, and metallurgy processes, reactions often have the features of unsteadiness, multistep, and multi-intermediates. Thermogravimetry-mass spectrum (TG-MS) is seen as a powerful tool to study reaction features. However, reaction details and reaction mechanics have not been effectively obtained directly from the ion current of TG-MS. Here, we provide a method of an equivalent characteristic spectrum analysis (ECSA) for analyzing the mass spectrum and giving the mass flow rate of reaction gases as precise as possible. The ECSA can effectively separate overlapping ion peaks and then eliminate the mass discrimination and temperature-dependent effect. Two example experiments are presented: (1) the decomposition of CaCO3 with evolved gas of CO2 and the decomposition of hydromagnesite with evolved gas of CO2 and H2O, to evaluate the ECSA on single-component system measurement and (2) the thermal pyrolysis of Zhundong coal with evolved gases of inorganic gases CO, H2, and CO2, and organic gases C2H4, C2H6, C3H8, C6H14, etc., to evaluate the ECSA on multi-component system measurement. Based on the successful calibration of the characteristic spectrum and relative sensitivity of specific gas and the ECSA on mass spectrum, we demonstrate that the ECSA accurately gives the mass flow rates of each evolved gas, including organic or inorganic gases, for not only single but multi-component reactions, which cannot be implemented by the traditional measurements.

Precise determination of the evolved gases&#39; flow rate is key to study the details of reactions. We provide a novel quantitative analysis method of equivalent characteristic spectrum analysis for thermogravimetry-mass spectrum analysis by establishing the calibration system of the characteristic spectrum and relative sensitivity, for obtaining the flow rate.

热重分析-质谱分析对演化气体反应的定量分析

During energy conversion, material production, and metallurgy processes, reactions often have the features of unsteadiness, multistep, and ...

工程学

Profiling Volatile Compounds in Blackcurrant Fruit using Headspace Solid-Phase Microextraction Coupled to Gas Chromatography-Mass Spectrometry

There is an increasing interest in measuring volatile organic compounds (VOCs) emitted by ripe fruits for the purpose of breeding varieties or cultivars with enhanced organoleptic characteristics and thus, to increase consumer acceptance. High-throughput metabolomic platforms have been recently developed to quantify a wide range of metabolites in different plant tissues, including key compounds responsible for fruit taste and aroma quality (volatilomics). A method using headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) is described here for the identification and quantification of VOCs emitted by ripe blackcurrant fruits, a berry highly appreciated for its flavor and health benefits.
Ripe fruits of blackcurrant plants (Ribes nigrum) were harvested and directly frozen in liquid nitrogen. After tissue homogenization to produce a fine powder, samples were thawed and immediately mixed with sodium chloride solution. Following centrifugation, the supernatant was transferred into a headspace glass vial containing sodium chloride. VOCs were then extracted using a solid-phase microextraction (SPME) fiber and a gas chromatograph coupled to an ion trap mass spectrometer. Volatile quantification was performed on the resulting ion chromatograms by integrating peak area, using a specific m/z ion for each VOC. Correct VOC annotation was confirmed by comparing retention times and mass spectra of pure commercial standards run under the same conditions as the samples. More than 60 VOCs were identified in ripe blackcurrant fruits grown in contrasting European locations. Among the identified VOCs, key aroma compounds, such as terpenoids and C6 volatiles, can be used as biomarkers for blackcurrant fruit quality. In addition, advantages and disadvantages of the method are discussed, including prospective improvements. Furthermore, the use of controls for batch correction and minimization of drift intensity have been emphasized.

A headspace solid-phase microextraction-gas-chromatography platform is described here for fast, reliable, and semi-automated volatile identification and quantification in ripe blackcurrant fruits. This technique can be used to increase knowledge about fruit aroma and to select cultivars with enhanced flavor for the purpose of breeding.

使用顶空固相微萃取与气相色谱-质谱联用分析黑醋栗果实中的挥发性化合物

There is an increasing interest in measuring volatile organic compounds (VOCs) emitted by ripe fruits for the purpose of breeding varieties or cultivars ...

生物化学

Versatile Dual-Inlet Sample Introduction System for Multi-Mode Single Particle Inductively Coupled Plasma Mass Spectrometry Analysis and Validation

Metal-containing nanoparticles (NP) can be characterized with inductively coupled plasma mass spectrometers (ICP-MS) in terms of their size and number concentration by using the single-particle mode of the instrument (spICP-MS). The accuracy of measurement depends on the setup, operational conditions of the instrument and specific parameters that are set by the user. The transport efficiency of the ICP-MS is crucial for the quantification of the NP and usually requires a reference material with homogenous size distribution and a known particle number concentration.
Currently, NP reference materials are available for only a few metals and in limited sizes. If particles are characterized without a reference standard, the results of both size and particle number may be biased. Therefore, a dual-inlet setup for characterizing nanoparticles with spICP-MS was developed to overcome this problem. This setup is based on a conventional introduction system consisting of a pneumatic nebulizer (PN) for nanoparticle solutions and a microdroplet generator (&#181;DG) for ionic calibration solutions. A new and flexible interface was developed to facilitate the coupling of &#181;DG, PN and the ICP-MS system. The interface consists of available laboratory components and allows for the calibration, nanoparticle (NP) characterization and cleaning of the arrangement, while the ICP-MS instrument is still running.
Three independent analysis modes are available for determining particle size and number concentration. Each mode is based on a different calibration principle. While mode I (counting) and mode III (&#181;DG) are known from the literature, mode II (sensitivity), is used to determine the transport efficiency by inorganic ionic standard solutions only. It is independent of NP reference materials. The &#181;DG based inlet system described here guarantees superior analyte sensitivities and, therefore, lower detection limits (LOD). The size dependent LODs achieved are less than 15 nm for all NP (Au, Ag, CeO2) investigated.

Here we provide a protocol for the use of a dual-inlet system for single particle inductively coupled mass spectrometry which allows for a standard independent nanoparticle characterization.

Metal-containing nanoparticles (NP) can be characterized with inductively coupled plasma mass spectrometers (ICP-MS) in terms of their size and number ...

Fruit Volatile Analysis Using an Electronic Nose

Numerous and diverse physiological changes occur during fruit ripening, including the development of a specific volatile blend that characterizes fruit aroma. Maturity at harvest is one of the key factors influencing the flavor quality of fruits and vegetables1. The validation of robust methods that rapidly assess fruit maturity and aroma quality would allow improved management of advanced breeding programs, production practices and postharvest handling. 
Over the last three decades, much research has been conducted to develop so-called electronic noses, which are devices able to rapidly detect odors and flavors2-4. Currently there are several commercially available electronic noses able to perform volatile analysis, based on different technologies. The electronic nose used in our work (zNose, EST, Newbury Park, CA, USA), consists of ultra-fast gas chromatography coupled with a surface acoustic wave sensor (UFGC-SAW). This technology has already been tested for its ability to monitor quality of various commodities, including detection of deterioration in apple5; ripeness and rot evaluation in mango6; aroma profiling of thymus species7; C6 volatile compounds in grape berries8; characterization of vegetable oil9 and detection of adulterants in virgin coconut oil10. 
This system can perform the three major steps of aroma analysis: headspace sampling, separation of volatile compounds, and detection. In about one minute, the output, a chromatogram, is produced and, after a purging cycle, the instrument is ready for further analysis. The results obtained with the zNose can be compared to those of other gas-chromatographic systems by calculation of Kovats Indices (KI). Once the instrument has been tuned with an alkane standard solution, the retention times are automatically converted into KIs. However, slight changes in temperature and flow rate are expected to occur over time, causing retention times to drift. Also, depending on the polarity of the column stationary phase, the reproducibility of KI calculations can vary by several index units11. A series of programs and graphical interfaces were therefore developed to compare calculated KIs among samples in a semi-automated fashion. These programs reduce the time required for chromatogram analysis of large data sets and minimize the potential for misinterpretation of the data when chromatograms are not perfectly aligned.
We present a method for rapid volatile compound analysis in fruit. Sample preparation, data acquisition and handling procedures are also discussed.

A rapid method for volatile compound analysis in fruit is described. The volatile compounds present in the headspace of a homogenate of the sample are rapidly separated and detected with ultra-fast gas chromatography (GC) coupled with a surface acoustic wave (SAW) sensor. A procedure for data handling and analysis is also discussed.

果实挥发分析，利用电子鼻

Numerous and diverse physiological changes occur during fruit ripening, including the development of a specific volatile blend that characterizes fruit ...

生物学

Introduction to Mass Spectrometry

Source: Laboratory of Dr. Khuloud Al-Jamal - King&#39;s College London

Mass spectrometry is an analytical chemistry technique that enables the identification of unknown compounds within a sample, the quantification of known materials, the determination of the structure, and chemical properties of different molecules.
A mass spectrometer is composed of an ionization source, an analyzer,&#160;and a detector. The process involves the ionization of chemical compounds to generate ions. When using inductively coupled plasma (ICP), samples containing elements of interest are introduced into argon plasma as aerosol droplets. The plasma dries the aerosol, dissociates the molecules, and then removes an electron from the components to be detected by the mass spectrometer. Other ionization methods such as electrospray ionization (ESI) and matrix assisted laser desorption ionization (MALDI) are used to analyze biological samples. Following the ionization procedure, ions are separated in the mass spectrometer according to their mass-to-charge ratio (m/z), and the relative abundance of each ion type is measured. Finally, the detector commonly consists in an electron multiplier where the collision of ions with a charged anode leads to a cascade of increasing number of electrons, which can be detected by an electrical circuit connected to a computer.
In this video, the procedure of ICP-MS analysis will be described by the detection of 56Fe as an example.