我们要感谢台湾科技部（拨款号：第104-2628-M-009-003-MY4号），为这项工作提供财政支持。

该协议假定所有步骤均按照相关的实验室安全规定进行。一些步骤使用商业手段 - 在这种情况下，需要遵循制造商的指导原则。处理有毒化学物质时，必须遵守MSDS的指导原则。定制设备4必须谨慎操作;特别是在处理加压气体和带电电线时。 1.准备标准溶液<ol><li>通过将10μL柠檬烯与990μL乙醇混合，制备6.2×10 -2 M柠檬烯储存在乙醇中的溶液。 </li><li>通过混合10μL6.2 x 10 -2柠檬烯，490μL乙醇和加入纯水至终体积为10 mL，制备10 mL 6.2 x 10 -5 M柠檬烯溶液。彻底摇匀容量瓶。 </li><li>将准备的标准溶液转移到具有隔垫的20-mL螺旋顶部顶空玻璃小瓶中米帽稀释的标准溶液可用于测试系统。 </li></ol> 2.准备样品<ol><li>通过在厨房挤压器上挤压新鲜的酸橙水果（切成两半）来获得酸橙汁。 </li><li>通过混合2 mL柠檬汁，500μL乙醇和加入纯水至最终体积为10 mL准备10 mL稀柠檬汁。彻底摇匀容量瓶。 </li><li>将准备的样品转移到具有隔垫帽的20-mL螺旋顶部顶空玻璃小瓶中。 </li></ol> 3.用标准解决方案填充真实样品<ol><li>第一标准添加：通过混合2 mL柠檬汁，10μL6.2 x 10 -2 M柠檬烯溶液，490μL乙醇，并加入纯水至终体积为10 mL，准备10 mL加标样品。彻底摇匀容量瓶。 </li><li>第二标准添加：通过混合2 mL柠檬汁，20μL6.2 x 10 -2 M柠檬酸制备10 mL加标样品e溶液，480μL乙醇，并加入纯水至终体积为10mL。彻底摇匀容量瓶。 </li></ol> 4.设置雾化提取系统<ol><li>将闪烁提取系统（ 图1 ） 4放在三重四极杆质谱仪的APCI源旁边。 </li><li>将二氧化碳气瓶连接到气泡提取系统的供气口。打开气体调节器中的阀门。将输出压力设置为1.5 bar（150 kPa）。 </li><li>将提取室出口连接到离子源入口。 </li><li>将发泡系统连接到12 V电源。 </li><li> 设置三重四极杆质谱仪的数据采集软件 （ 图2 ）。 在正离子多反应监测（MRM）模式下，用氩气作为碰撞，用APCI光源操作仪器加油站。 <ol><li>运行数据采集软件。 </li><li>选择“仅LCMS8030”选项。 </li><li>选择选项“MS开/关”。 </li><li>设置去溶剂化温度线至250℃，和分钟-1干燥气体至15升的流量。等待每个仪器参数的值与预设值相同。 </li><li>选择MS数据采集方法文件。 </li><li>确保碰撞电压为-20 V，前体离子m / z为137，碎片离子m / z为81和95 </li><li>点击“开始单次运行”按钮。 </li><li>键入文件名。 </li><li>选择文件路径。 </li><li>转到第5节（“进行泡沫提取”）。 </li><li>选择选项“MS开/关”。 </li><li>关闭软件窗口。 </li><li>勾选“雾化气体关闭”，“DL加热器关闭”，“热块关闭”和“干气关闭”。点击“确定”＃34 ;. </li></ol></li></ol> 5.进行气泡提取<ol><li>通过使用螺丝钉将样品瓶放入精油萃取系统。萃取系统在室温（〜25℃）下运行。 </li><li>按fizzy提取系统的LCD屏幕上的“开始”按钮。 </li><li>等待自动化嘶嘶声提取过程执行（ 图3 ）。观察三重四极杆质谱仪屏幕上离子信号的发展。 注意：自动执行以下步骤：样品顶空在60秒内用二氧化碳冲洗。样品在二十六秒钟内用二氧化碳加压。搅拌马达开启。样品减压形成多个气泡。在后期阶段，搅拌马达开启以增加起泡。 </li><li>取出（拧下）样品瓶。 </li><li>用纤维素组织擦拭样品搅拌轴。 </li><li>洗涤搅拌sp放入乙醇，再次用纤维素组织擦拭。 </li><li>该系统已准备好分析另一个样品（重复步骤5.1-5.6）。 </li><li>关闭电源。 </li><li>从离子源中断开发泡管。 </li><li>关闭气瓶的阀门，并断开气体管道。 </li></ol>数据分析<ol><li> 将三重四极杆质谱仪的数据采集软件的m / z 81的离子流输出到ASCII文件（ 图4 ）。 注意：在本演示中不使用m / z 95处的离子电流。 <ol><li>运行数据采集软件。选择“Postrun”选项。 </li><li>选择“选择项目（文件夹）”选项，然后选择数据文件。 </li><li>点击“文件”菜单，选择“导出数据”/“导出数据为ASCII”。 </li><li>选择 ＆＃34;输出文件“，并选择文件路径，选择”MS色谱图（MC）“。 </li></ol></li><li> 将原始数据集导入峰集成软件，并测量峰面积（ 图5 ）。设置：线性基线; HVL功能。 <ol><li>运行峰值集成软件。 </li><li>从“文件”菜单中选择“导入”选项。点击“是”按钮。 </li><li>选择X和Y列中的数据。点击“确定”按钮。选择“AutoFit Peaks I Residuals”选项。 </li><li>半自动适应提取峰。确保拟合曲线遵循实验数据点。选择“List Peak Estimates”列表。选择选项“ASCII编辑器”。 </li><li>将拟合结果复制到“剪贴板”。 </li></ol></li><li> 在数据分析软件中将测量的峰值区域输入电子表格（ 图6 ）。 &lt;OL&gt; <li>运行数据分析软件。 </li><li>输入X列中的浓度值和Y列中的峰面积值。从“Plot”菜单中选择“Symbol”/“Scatter”选项。从“分析”菜单中选择“调整”/“适合线性”选项。 </li></ol></li><li>根据以下公式计算稀释的真实样品中柠檬烯的浓度： <img alt="公式1" src="/files/ftp_upload/56008/56008eq1.jpg" /> 其中我是线性函数的截距，而S是斜率。 </li><li>基于以下公式计算原始实际样品（稀释前）中柠檬烯的浓度： <img alt="方程式2" src="/files/ftp_upload/56008/56008eq2.jpg" /> 其中DF是稀释因子（这里是5）。 </li></ol>

<ol>
	<li>McCallum, R. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decompression+sickness:+a+review.">Decompression sickness: a review.</a> Brit J Industr Med. 25, 4-21 (1968).</li><li>Pawliszyn, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Comprehensive Sampling and Sample Preparation. , (2012).</li><li>Wang, T., Lenahan, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+volatile+halocarbons+in+water+by+purge-closed+loop+gas+chromatography.">Determination of volatile halocarbons in water by purge-closed loop gas chromatography.</a> Bull Environ Contam Toxicol. 32, 429-438 (1984).</li><li>Chang, C. -. H., Urban, P. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fizzy+extraction+of+volatile+and+semivolatile+compounds+into+the+gas+phase.">Fizzy extraction of volatile and semivolatile compounds into the gas phase.</a> Anal Chem. 88, 8735-8740 (2016).</li><li>Zougagh, M., Valc&#225;rcel, M., R&#237;os, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Supercritical+fluid+extraction:+a+critical+review+of+its+analytical+usefulness.">Supercritical fluid extraction: a critical review of its analytical usefulness.</a> Trends Anal Chem. 23, 399-405 (2004).</li><li>Urban, P. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Universal+electronics+for+miniature+and+automated+chemical+assays.">Universal electronics for miniature and automated chemical assays.</a> Analyst. 140, 963-975 (2015).</li><li>Urban, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-built+labware+stimulates+creativity.">Self-built labware stimulates creativity.</a> Nature. 532, 313 (2016).</li><li>Chen, H., Venter, A., Cooks, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extractive+electrospray+ionization+for+direct+analysis+of+undiluted+urine,+milk+and+other+complex+mixtures+without+sample+preparation.">Extractive electrospray ionization for direct analysis of undiluted urine, milk and other complex mixtures without sample preparation.</a> Chem Commun. , 2042-2044 (2006).</li><li>Haddad, R., Sparrapan, R., Kotiaho, T., Eberlin, M. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Easy+ambient+sonic-spray+ionization-membrane+interface+mass+spectrometry+for+direct+analysis+of+solution+constituents.">Easy ambient sonic-spray ionization-membrane interface mass spectrometry for direct analysis of solution constituents.</a> Anal Chem. 80, 898-903 (2008).</li><li>Dixon, R. B., Sampson, J. S., Muddiman, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+multiply+charged+peptides+and+proteins+by+radio+frequency+acoustic+desorption+and+ionization+for+mass+spectrometric+detection.">Generation of multiply charged peptides and proteins by radio frequency acoustic desorption and ionization for mass spectrometric detection.</a> J Am Soc Mass Spectrom. 20, 597-600 (2009).</li><li>Wu, C. -. I., Wang, Y. -. S., Chen, N. G., Wu, C. -. Y., Chen, C. -. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasound+ionization+of+biomolecules.">Ultrasound ionization of biomolecules.</a> Rapid Commun Mass Spectrom. 24, 2569-2574 (2010).</li><li>Lo, T. -. J., Chen, T. -. Y., Chen, Y. -. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Study+of+salt+effects+in+ultrasonication-assisted+spray+ionization+mass+spectrometry.">Study of salt effects in ultrasonication-assisted spray ionization mass spectrometry.</a> J Mass Spectrom. 47, 480-483 (2012).</li><li>Urban, P. L., Chen, Y. -. C., Wang, Y. -. 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> Time-Resolved Mass Spectrometry: From Concept to Applications. , (2016).</li><li>Peacock, P. M., Zhang, W. -. J., Trimpin, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advances+in+ionization+for+mass+spectrometry.">Advances in ionization for mass spectrometry.</a> Anal Chem. 89, 372-388 (2017).</li><li>Hu, J. -. B., Chen, S. -. Y., Wu, J. -. T., Chen, Y. -. C., Urban, P. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automated+system+for+extraction+and+instantaneous+analysis+of+millimeter-sized+samples.">Automated system for extraction and instantaneous analysis of millimeter-sized samples.</a> RSC Adv. 4, 10693-10701 (2014).</li><li>Chen, S. -. Y., Urban, P. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On-line+monitoring+of+Soxhlet+extraction+by+chromatography+and+mass+spectrometry+to+reveal+temporal+extract+profiles.">On-line monitoring of Soxhlet extraction by chromatography and mass spectrometry to reveal temporal extract profiles.</a> Anal Chim Acta. 881, 74-81 (2015).</li><li>Hsieh, K. -. T., Liu, P. -. H., Urban, P. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automated+on-line+liquid-liquid+extraction+system+for+temporal+mass+spectrometric+analysis+of+dynamic+samples.">Automated on-line liquid-liquid extraction system for temporal mass spectrometric analysis of dynamic samples.</a> Anal Chim Acta. 894, 35-43 (2015).</li><li>Veach, B. T., Mudalige, T. K., Rye, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RapidFire+mass+spectrometry+with+enhanced+throughput+as+an+alternative+to+liquid&#8722;liquid+salt+assisted+extraction+and+LC/MS+analysis+for+sulfonamides+in+honey.">RapidFire mass spectrometry with enhanced throughput as an alternative to liquid&#8722;liquid salt assisted extraction and LC/MS analysis for sulfonamides in honey.</a> Anal Chem. , (2017).</li><li>Carroll, D. I., Dzidic, I., Stillwell, R. N., Horning, M. G., Horning, E. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subpicogram+detection+system+for+gas+phase+analysis+based+upon+atmospheric+pressure+ionization+(API)+mass+spectrometry.">Subpicogram detection system for gas phase analysis based upon atmospheric pressure ionization (API) mass spectrometry.</a> Anal Chem. 46, 706-710 (1974).</li><li>Carroll, D. I., Dzidic, I., Stillwell, R. N., Haegele, K. D., Horning, E. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atmospheric+pressure+ionization+mass+spectrometry.+Corona+discharge+ion+source+for+use+in+a+liquid+chromatograph-mass+spectrometer-computer+analytical+system.">Atmospheric pressure ionization mass spectrometry. Corona discharge ion source for use in a liquid chromatograph-mass spectrometer-computer analytical system.</a> Anal Chem. 47, 2369-2373 (1975).</li><li>Hakim, I. A., McClure, T., Liebler, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessing+dietary+D-limonene+intake+for+epidemiological+studies.">Assessing dietary D-limonene intake for epidemiological studies.</a> J Food Compos Anal. 13, 329-336 (2000).</li></ol>

作者没有什么可以披露的。

<html>一些聪明的方法来提供样品质谱仪在过去的三个十年中进行的研究，开发（ 例如 ，参考8，9，10，11，12，13，14）。这些研究的目标之一是简化样品的准备以进行分析。为了实现这一目标，引入了离子源设计的?...

在自然界和日常生活中观察到的各种现象与气液相平衡有关。二氧化碳在升高的压力下溶解在软和含酒精的饮料中。当一瓶这样的泡沫饮料打开时，压力下降，气泡冲向液面。在这种情况下，泡腾可改善饮料的感官特性。气泡的释放也是减压病（“弯”）的主要原因1 。由于突然的减压，气泡形成在潜水员身上。患有减压病的人在高压室治疗。 气泡在分析化学中有各种应用。值得注意的是，喷射方法依靠通过液体样品的气泡来提取挥发性化合物2 。例如，称为“吹扫闭合回路”的方法与气相色谱相结合，可以快速分析二次溶解的挥发物3 。虽然喷射可以随着时间的推移不断地提取挥发物，但它并不局限于空间或时间。释放的气相物种需要被捕获，并且在某些情况下通过应用温度程序或使用吸附剂来浓缩。因此，需要引入新的在线样品处理策略，这可以减少步骤的数量，同时在空间或时间上浓缩挥发性分析物。 为了解决从液体样品中提取挥发性化合物并进行在线分析的挑战，我们最近推出了“fizzy extract” 4 。这种新技术利用了泡腾现象。简而言之，通过施加超压并搅拌样品，首先将载气（这里是二氧化碳）溶解在样品中。然后，样品室突然减压。突然减压导致形成许多载气泡<html>在样品液体中。这些泡沫有助于将溶解的分析物质从液体释放到气相。释放的分析物立即转移到质谱仪，在时域产生信号。因为分析物种的释放被限制在短时间（几秒），所以时间信号具有高幅度和高的信噪比。 泡沫萃取过程中所涉及的压力非常低（约150 kPa） 4 ;远远低于超临界流体萃取5 （ 例如 ≥10MPa）。该技术不需要使用任何特殊的消耗品（色谱柱，墨盒）。只有少量的溶剂用于稀释和清洗。提取装置可以由具有中等技术技能的化学家使用广泛可用的部件组装4 ;例如，开源电子模块“&gt; 6,7。碳酸提取可耦合上线用装有大气压化学电离（APCI）接口。由于气相萃取液转移至离子源，碳酸提取的操作基本上不污染脆弱现代质谱仪部分质谱仪。 这个可视化实验文章的目的是指导观众在简单的分析任务中如何实施fizzy提取。虽然fizzy提取系统的核心是我们以前的报告4所述 ，但已经引入了几项改进措施，使操作更为直接。配有LCD屏幕屏蔽的微控制器已经并入系统中以实时显示键提取参数。所有功能都在微控制器脚本中编程，并且不再需要使用外部计算机来c控制提取系统。

<table border="0" cellpadding="0" cellspacing="0" width="963">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Water</td>
			<td style="width:197px;">Fisher</td>
			<td style="width:160px;">W6212</td>
			<td style="width:191px;">Diluent</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Ethanol</td>
			<td style="width:197px;">Sigma-Aldrich</td>
			<td style="width:160px;">32221-2.5L</td>
			<td>Diluent</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">(R)-(+)-Limonene</td>
			<td style="width:197px;">Sigma-Aldrich</td>
			<td style="width:160px;">183164-100ML</td>
			<td>Standard</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Carbon dioxide</td>
			<td style="width:197px;">ChiaLung</td>
			<td>n/a</td>
			<td>Carrier gas</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Cellulose tissue, Kimwipes Kimtech</td>
			<td style="width:197px;">Kimberly-Clark</td>
			<td>34120</td>
			<td>Used for cleaning</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Triple quadrupole mass spectrometer</td>
			<td style="width:197px;">Shimadzu</td>
			<td style="width:160px;">LCMS-8030</td>
			<td>Detection system</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">Atmospheric pressure chemical ionization interface</td>
			<td style="width:197px;">Shimadzu</td>
			<td style="width:160px;">Duis</td>
			<td>Ion source</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">20-mL screw top headspace glass vial with septum cap</td>
			<td style="width:197px;">Thermo Fisher Scientific</td>
			<td style="width:160px;">D-52379</td>
			<td>Sample vial</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">LabSolutions software</td>
			<td style="width:197px;">Shimadzu</td>
			<td>n/a</td>
			<td>version 5.82</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">PeakFit software</td>
			<td style="width:197px;">Systat Software</td>
			<td>n/a</td>
			<td>version 4.12</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:415px;">OriginPro software</td>
			<td style="width:197px;">OriginLab</td>
			<td>n/a</td>
			<td>version 8</td>
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fizzy extraction of volatile organic compounds combined with atmospheric pressure chemical ionization quadrupole mass spectrometry

溶解在液体样品中的挥发性和半挥发性化合物的化学分析可能具有挑战性。溶解的组分需要进入气相，并有效转移到检测系统。泡沫提取利用泡腾现象。首先，通过施加超压并搅拌样品，将载气（这里为二氧化碳）溶解在样品中。第二，样品室突然减压。减压导致在样品液体中形成许多载气泡。这些泡沫有助于将溶解的分析物质从液体释放到气相。释放的分析物立即转移到三重四极杆质谱仪的大气压化学电离界面。可离子化分析物种在时域中产生质谱信号。因为分析物质的释放发生在短时间内（几秒钟）onds），时间信号具有高幅度和高信噪比。然后，时间峰值的振幅和面积可以与经过精细提取的液体样品中的分析物的浓度相关联，这使得能够进行定量分析。泡沫提取的优点包括：简单，速度快，化学品（溶剂）使用有限。

开始时，使用标准解决方案测试嘶嘶声提取系统。随后，分析了标准样品和真实样品。提取事件的时间峰面积与经过精炼提取的液体样品中分析物的浓度相关，可进行定量分析。在这里，我们执行了双重标准添加，以演示该技术的定量能力（ 图7 ）。线性回归导致以下功能（ 图8 ）： <p class="jove_content" fo:keep-together.within-page=...

Watch this Scientific Journal Video about Fizzy Extraction of Volatile Organic Compounds Combined with Atmospheric Pressure Chemical Ionization Quadrupole Mass Spectrometry at JoVE.com

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

闪光提取是用于分析挥发性和半挥发性化合物的新的实验室技术。通过施加超压并搅拌样品将载气溶解在液体样品中。然后将样品室减压。分析物种由于发泡而释放到气相中。

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 ...

fizzy-extraction-volatile-organic-compounds-combined-with-atmospheric

Research

Education

JoVE Core

JoVE Journal

Analytical Chemistry

Chemistry

Unit 1

Mass Spectrometry Fragmentation Methods

SCIENTISTS IN ACTION

7.6K 次观看.  National Chiao Tung University. 闪光提取是用于分析挥发性和半挥发性化合物的新的实验室技术。通过施加超压并搅拌样品将载气溶解在液体样品中。然后将样品室减压。分析物种由于发泡而释放到气相中。 

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

High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems

The high pressure sapphire cell apparatus was constructed to visually determine the composition of multiphase systems without physical sampling. Specifically, the sapphire cell enables visual data collection from multiple loadings to solve a set of material balances to precisely determine phase composition. Ternary phase diagrams can then be established to determine the proportion of each component in each phase at a given condition. In principle, any ternary system can be studied although ternary systems (gas-liquid-liquid) are the specific examples discussed herein. For instance, the ternary THF-Water-CO2 system was studied at 25 and 40&#160;&#176;C and is described herein. Of key importance, this technique does not require sampling. Circumventing the possible disturbance of the system equilibrium upon sampling, inherent measurement errors, and technical difficulties of physically sampling under pressure is a significant benefit of this technique. Perhaps as important, the sapphire cell also enables the direct visual observation of the phase behavior. In fact, as the CO2 pressure is increased, the homogeneous THF-Water solution phase splits at about 2 MPa. With this technique, it was possible to easily and clearly observe the cloud point and determine the composition of the newly formed phases as a function of pressure.
The data acquired with the sapphire cell technique can be used for many applications. In our case, we measured swelling and composition for tunable solvents, like gas-expanded liquids, gas-expanded ionic liquids and Organic Aqueous Tunable Systems (OATS)1-4. For the latest system, OATS, the high-pressure sapphire cell enabled the study of (1) phase behavior as a function of pressure and temperature, (2) composition of each phase (gas-liquid-liquid) as a function of pressure and temperature and (3) catalyst partitioning in the two liquid phases as a function of pressure and composition. Finally, the sapphire cell is an especially effective tool to gather accurate and reproducible measurements in a timely fashion.

High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems

The high pressure sapphire cell apparatus is a unique tool to study, without sampling, phase behavior under a wide range of pressures. Using a cathetometer, very precise volume measurements can be recorded to measure liquid expansion and phase composition. Thus, this synthetic method enables the study of (1) phase equilibria of multi-component mixtures and (2) the partition behavior of catalyst or model compounds as a function of pressure.

高压蓝宝石细胞对CO的相平衡测量<sub&gt; 2</sub&gt; /有机/水系统

The high pressure sapphire cell apparatus was constructed to visually determine the composition of multiphase systems without physical sampling. ...

科研

化学

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

This video presents a protocol for the mass spectrometrical analysis of volatile and oxidation sensitive compounds using electron impact ionization. The analysis of volatile and oxidation sensitive compounds by mass spectrometry is not easily achieved, as all state-of-the-art mass spectrometric methods require at least one sample preparation step, e.g., dissolution and dilution of the analyte (electrospray ionization), co-crystallization of the analyte with a matrix compound (matrix-assisted laser desorption/ionization), or transfer of the prepared samples into the ionization source of the mass spectrometer, to be conducted under atmospheric conditions. Here, the use of a sample inlet system is described which enables the analysis of volatile metal organyls, silanes, and phosphanes using a sector field mass spectrometer equipped with an electron impact ionization source. All sample preparation steps and the sample introduction into the ion source of the mass spectrometer take place either under air-free conditions or under vacuum, enabling the analysis of compounds highly susceptible to oxidation. The presented technique is especially of interest for inorganic chemists, working with metal organyls, silanes, or phosphanes, which have to be handled using inert conditions, such as the Schlenk technique. The principle of operation is presented in this video.

This video presents a protocol for the mass spectrometrical analysis of volatile and oxidation sensitive compounds using electron impact ionization. The presented technique is especially of interest for inorganic chemists, working with metal organyls, silanes, or phosphanes which have to be handled using inert conditions, such as the Schlenk technique.

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 ...

A Study of the Complexation of Mercury(II) with Dicysteinyl Tetrapeptides by Electrospray Ionization Mass Spectrometry

In this study we evaluated a method for the characterization of complexes, formed in different relative ratios of mercury(II) to dicysteinyl tetrapeptide, by electrospray ionization orbitrap mass spectrometry. This strategy is based on previous successful characterization of mercury-dicysteinyl complexes involving tripeptides by utilizing mass spectrometry among other techniques. Mercury(II) chloride and a dicysteinyl tetrapeptide were incubated in a degassed buffered medium at varying stoichiometric ratios. The complexes formed were subsequently analyzed on an electrospray mass spectrometer consisting of a hybrid linear ion- and orbi- trap mass analyzer. The electrospray ionization mass spectrometry (ESI-MS) spectra were acquired in the positive mode and the observed peaks were then analyzed for distinct mercury isotopic distribution patterns and associated monoisotopic peak. This work demonstrates that an accurate stoichiometry of mercury and peptide in the complexes formed under specified electrospray ionization conditions can be determined by using high resolution ESI MS based on distinct mercury isotopic distribution patterns.

A Study of the Complexation of MercuryII with Dicysteinyl Tetrapeptides by Electrospray Ionization Mass Spectrometry

The characterization of complexes formed in different relative ratios of mercury(II) to dicysteinyl tetrapeptides by electrospray ionization orbitrap mass spectrometry is presented.

汞（II）与Dicysteinyl四肽的络合的电喷雾质​​谱研究

In this study we evaluated a method for the characterization of complexes, formed in different relative ratios of mercury(II) to dicysteinyl tetrapeptide, ...

Visualization of Ambient Mass Spectrometry with the Use of Schlieren Photography

This manuscript outlines how to visualize mass spectrometry ambient ionization sources using schlieren photography. In order to properly optimize the mass spectrometer, it is necessary to characterize and understand the physical principles of the source. Most commercial ambient ionization sources utilize jets of nitrogen, helium, or atmospheric air to facilitate the ionization of the analyte. As a consequence, schlieren photography can be used to visualize the gas streams by exploiting the differences in refractive index between the streams and ambient air for visualization in real time. The basic setup requires a camera, mirror, flashlight, and razor blade. When properly configured, a real time image of the source is observed by watching its reflection. This allows for insight into the mechanism of action in the source, and pathways to its optimization can be elucidated. Light is shed on an otherwise invisible situation.

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 ...

Real-time Breath Analysis by Using Secondary Nanoelectrospray Ionization Coupled to High Resolution Mass Spectrometry

Exhaled volatile organic compounds (VOCs) have aroused considerable interest, since they can serve as biomarkers for disease diagnosis and environmental exposure in a non-invasive manner. In this work, we present a protocol to characterize the exhaled VOCs in real time by using secondary nanoelectrospray ionization coupled to high resolution mass spectrometry (Sec-nanoESI-HRMS). The homemade Sec-nanoESI source was readily set up based on a commercial nanoESI source. Hundreds of peaks were observed in the background-subtracted mass spectra of exhaled breath, and the mass accuracy values are -4.0-13.5 ppm and -20.3-1.3 ppm in the positive and negative ion detection modes, respectively. The peaks were assigned with accurate elemental composition according to the accurate mass and isotopic pattern. Less than 30 s is used for one exhalation measurement, and it takes approximately 7 min for six replicated measurements.

A protocol for characterizing chemical composition of exhaled breath in real time by using secondary nanoelectrospray ionization coupled to high resolution mass spectrometry is demonstrated.

利用二次 Nanoelectrospray 电离耦合高分辨质谱的实时呼吸分析

Exhaled volatile organic compounds (VOCs) have aroused considerable interest, since they can serve as biomarkers for disease diagnosis and environmental ...

Characterization of Synthetic Polymers via Matrix Assisted Laser Desorption Ionization Time of Flight (MALDI-TOF) Mass Spectrometry

There are many techniques that can be employed in the characterization of synthetic homopolymers, but few provide as useful of information for end group analysis as matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS). This tutorial demonstrates methods for optimization of the sample preparation, spectral acquisition, and data analysis of synthetic polymers using MALDI-TOF MS. Critical parameters during sample preparation include the selection of the matrix, identification of an appropriate cationization salt, and tuning the relative proportions of the matrix, cation, and analyte. The acquisition parameters, such as mode (linear or reflector), polarization (positive or negative), acceleration voltage, and delay time, are also important. Given some knowledge of the chemistry involved to synthesize the polymer and optimizing both the data acquisition parameters and the sample preparation conditions, spectra should be obtained with sufficient resolution and mass accuracy to enable the unambiguous determination of the end groups of most homopolymers (masses below 10,000) in addition to the repeat unit mass and the overall molecular weight distribution. Though demonstrated on a limited set of polymers, these general techniques are applicable to a much wider range of synthetic polymers for determining mass distributions, though end group determination is only possible for homopolymers with narrow dispersity.

Characterization of Synthetic Polymers via Matrix Assisted Laser Desorption Ionization Time of Flight MALDI-TOF Mass Spectrometry

A protocol for the matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) characterization of synthetic polymers is described including the optimization of sample preparation, spectral acquisition, and data analysis.

基质辅助激光解吸电离飞行时间 (MALDI) 质谱法表征合成聚合物

There are many techniques that can be employed in the characterization of synthetic homopolymers, but few provide as useful of information for end group ...

Analysis of Complex Molecules and Their Reactions on Surfaces by Means of Cluster-Induced Desorption/Ionization Mass Spectrometry

Desorption/Ionization Induced by Neutral SO2 Clusters (DINeC) is employed as a very soft and efficient desorption/ionization technique for mass spectrometry (MS) of complex molecules and their reactions on surfaces. DINeC is based on a beam of SO2 clusters impacting on the sample surface at low cluster energy. During cluster-surface impact, some of the surface molecules are desorbed and ionized via dissolvation in the impacting cluster; as a result of this dissolvation-mediated desorption mechanism, low cluster energy is sufficient and the desorption process is extremely soft. Both surface adsorbates and molecules of which the surface is composed of can be analyzed. Clear and fragmentation-free spectra from complex molecules such as peptides and proteins are obtained. DINeC does not require any special sample preparation, in particular no matrix has to be applied. The method yields quantitative information on the composition of the samples; molecules at a surface coverage as low as 0.1 % of a monolayer can be detected. Surface reactions such as H/D exchange or thermal decomposition can be observed in real-time and the kinetics of the reactions can be deduced. Using a pulsed nozzle for cluster beam generation, DINeC can be efficiently combined with ion trap mass spectrometry. The matrix-free and soft nature of the DINeC process in combination with the MSn capabilities of the ion trap allows for very detailed and unambiguous analysis of the chemical composition of complex organic samples and organic adsorbates on surfaces.

Neutral SO2 clusters of low kinetic energy (&#60; 0.8 eV/constituent) are used to desorb complex surface molecules such as peptides or lipids for further analysis by means of mass spectrometry using an ion trap mass spectrometer. No special sample preparation is required, and real-time observation of reactions is possible.

聚类诱导解吸/电电质谱法对复杂分子及其在表面的反应分析

Desorption/Ionization Induced by Neutral SO2 Clusters (DINeC) is employed as a very soft and efficient desorption/ionization technique for mass ...

Mass Spectrometry-Guided Genome Mining as a Tool to Uncover Novel Natural Products

The chemical space covered by natural products is immense and widely unrecognized. Therefore, convenient methodologies to perform wide-ranging evaluation of their functions in nature and potential human benefits (e.g., for drug discovery applications) are desired. This protocol describes the combination of genome mining (GM) and molecular networking (MN), two contemporary approaches that match gene cluster-encoded annotations in whole genome sequencing with chemical structure signatures from crude metabolic extracts. This is the first step towards the discovery of new natural entities. These concepts, when applied together, are defined here as MS-guided genome mining. In this method, the main components are previously designated (using MN), and structurally related new candidates are associated with genome sequence annotations (using GM). Combining GM and MN is a profitable strategy to target new molecule backbones or harvest metabolic profiles in order to identify analogues from already known compounds.

A mass spectrometry-guided genome mining protocol is established and described here. It is based on genome sequence information and LC-MS/MS analysis and aims to facilitate identification of molecules from complex microbial and plant extracts.

质谱导览基因组挖掘作为发现新天然产品的工具

The chemical space covered by natural products is immense and widely unrecognized. Therefore, convenient methodologies to perform wide-ranging evaluation ...

Gas Chromatography-Mass Spectrometry Paired with Total Vaporization Solid-Phase Microextraction as a Forensic Tool

Gas Chromatography &#8211; Mass Spectrometry (GC-MS) is a frequently used technique for the analysis of numerous analytes of forensic interest, including controlled substances, ignitable liquids, and explosives. GC-MS can be coupled with Solid-Phase Microextraction (SPME), in which a fiber with a sorptive coating is placed into the headspace above a sample or immersed in a liquid sample. Analytes are sorbed onto the fiber which is then placed inside the heated GC inlet for desorption. Total Vaporization Solid-Phase Microextraction (TV-SPME) utilizes the same technique as immersion SPME but immerses the fiber into a completely vaporized sample extract. This complete vaporization results in a partition between only the vapor phase and the SPME fiber without interference from a liquid phase or any insoluble materials. Depending upon the boiling point of the solvent used, TV-SPME allows for large sample volumes (e.g., up to hundreds of microliters). On-fiber derivatization may also be performed using TV-SPME. TV-SPME has been used to analyze drugs and their metabolites in hair, urine, and saliva. This simple technique has also been applied to street drugs, lipids, fuel samples, post-blast explosive residues, and pollutants in water. This paper highlights the use of TV-SPME to identify illegal adulterants in very small samples (microliter quantities) of alcoholic beverages. Both gamma-hydroxybutyrate (GHB) and gamma-butyrolactone (GBL) were identified at levels that would be found in spiked drinks. Derivatization by a trimethylsilyl agent allowed for conversion of the aqueous matrix and GHB into their TMS derivatives. Overall, TV-SPME is quick, easy, and requires no sample preparation aside from placing the sample into a headspace vial.

Total Vaporization Solid Phase Microextraction (TV-SPME) completely vaporizes a liquid sample whilst analytes are sorbed onto a SPME fiber. This allows for partitioning of the analyte between only the solvent vapor and the SPME fiber coating.

气相色谱-质量光谱学与总蒸发固体相微切成一对，作为取证工具

Gas Chromatography &#8211; Mass Spectrometry (GC-MS) is a frequently used technique for the analysis of numerous analytes of forensic interest, including ...

Organic Solvent-Based Protein Precipitation for Robust Proteome Purification Ahead of Mass Spectrometry

While multiple advances in mass spectrometry (MS) instruments have improved qualitative and quantitative proteome analysis, more reliable front-end approaches to isolate, enrich, and process proteins ahead of MS are critical for successful proteome characterization. Low, inconsistent protein recovery and residual impurities such as surfactants are detrimental to MS analysis. Protein precipitation is often considered unreliable, time-consuming, and technically challenging to perform compared to other sample preparation strategies. These concerns are overcome by employing optimal protein precipitation protocols. For acetone precipitation, the combination of specific salts, temperature control, solvent composition, and precipitation time is critical, while the efficiency of chloroform/methanol/water precipitation depends on proper pipetting and vial manipulation. Alternatively, these precipitation protocols are streamlined and semi-automated within a disposable spin cartridge. The expected outcomes of solvent-based protein precipitation in the conventional format and using a disposable, two-stage filtration and extraction cartridge are illustrated in this work. This includes the detailed characterization of proteomic mixtures by bottom-up LC-MS/MS analysis. The superior performance of SDS-based workflows is also demonstrated relative to non-contaminated protein.

The present protocol describes solvent-based protein precipitation under controlled conditions for robust and rapid recovery and purification of proteome samples prior to mass spectrometry.

有机溶剂基蛋白质沉淀，在质谱分析之前实现强大的蛋白质组纯化

While multiple advances in mass spectrometry (MS) instruments have improved qualitative and quantitative proteome analysis, more reliable front-end ...