Name: standardized identification of compound structure in tibetan medicine using ion trap mass spectrometry and multiple-stage fragmentation analysis
Uploaded: 2023-03-17T14:10:00
Description: Watch this Scientific Journal Video about Standardized Identification of Compound Structure in Tibetan Medicine Using Ion Trap Mass Spectrometry and Multiple-Stage Fragmentation Analysis at JoVE.com

这项工作由成都中医药大学杏林人才计划（030058191号）、四川省自然科学基金（2022NSFSC1470）和国家自然科学基金（82204765）资助。

1. 样品制备
<ol><li>准确称取 1 g AMS 样品，并将其放入装有 30 mL 80% 甲醇的锥形烧瓶中。将混合物转移到超声浴超声仪中，在25°C下提取30分钟。 将样品以14，000 x g 离心5分钟。 注意：超声波浴超声仪的频率为40 KHz。</li>
	<li>准备注射器和微孔膜过滤器（0.22μm，仅有机）。将上清液过滤到 2 mL 样品瓶中。</li>
</ol>2. 质谱设置
<ol><li>打开真空泵的?...

<ol>
	<li>Chen, X. -. F., Wu, H. -. T., Tan, G. -. G., Zhu, Z. -. Y., Chai, Y. -. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liquid+chromatography+coupled+with+time-of-flight+and+ion+trap+mass+spectrometry+for+qualitative+analysis+of+herbal+medicines.">Liquid chromatography coupled with time-of-flight and ion trap mass spectrometry for qualitative analysis of herbal medicines.</a> Journal of Pharmaceutical Analysis. 1 (4), 235-245 (2011).</li><li>Ou, C., 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=Systematically+investigating+the+pharmacological+mechanism+of+Dazhu+Hongjingtian+in+the+prevention+and+treatment+of+acute+mountain+sickness+by+integrating+UPLC/Q-TOF-MS/MS+analysis+and+network+pharmacology.">Systematically investigating the pharmacological mechanism of Dazhu Hongjingtian in the prevention and treatment of acute mountain sickness by integrating UPLC/Q-TOF-MS/MS analysis and network pharmacology.</a> Journal of Pharmaceutical and Biomedical Analysis. 179, 113028 (2020).</li><li>Kind, T., 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=Identification+of+small+molecules+using+accurate+mass+MS/MS+search.">Identification of small molecules using accurate mass MS/MS search.</a> Mass Spectrometry Reviews. 37 (4), 513-532 (2018).</li><li>Phetsanthad, A., Vu, N. Q., Li, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multi-faceted+mass+spectrometric+investigation+of+neuropeptides+in+Callinectes+sapidus.">Multi-faceted mass spectrometric investigation of neuropeptides in Callinectes sapidus.</a> Journal of Visualized Experiments. (183), e63322 (2022).</li><li>Seetaloo, N., Phillips, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Millisecond+hydrogen/deuterium-exchange+mass+spectrometry+for+the+study+of+alpha-synuclein+structural+dynamics+under+physiological+conditions.">Millisecond hydrogen/deuterium-exchange mass spectrometry for the study of alpha-synuclein structural dynamics under physiological conditions.</a> Journal of Visualized Experiments. (184), e64050 (2022).</li><li>Karas, B. F., 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=Dose+uptake+of+platinum-and+ruthenium-based+compound+exposure+in+zebrafish+by+inductively+coupled+plasma+mass+spectrometry+with+broader+applications.">Dose uptake of platinum-and ruthenium-based compound exposure in zebrafish by inductively coupled plasma mass spectrometry with broader applications.</a> Journal of Visualized Experiments. (182), e6358 (2022).</li><li>Chang, H. -. L., 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=Uracil-DNA+glycosylase+assay+by+matrix-assisted+laser+desorption/ionization+time-of-flight+mass+spectrometry+analysis.">Uracil-DNA glycosylase assay by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis.</a> Journal of Visualized Experiments. (182), e63089 (2022).</li><li>Wang, S., 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=Structural+characterization+and+identification+of+major+constituents+in+Jitai+tablets+by+high-performance+liquid+chromatography/diode-array+detection+coupled+with+electrospray+ionization+tandem+mass+spectrometry.">Structural characterization and identification of major constituents in Jitai tablets by high-performance liquid chromatography/diode-array detection coupled with electrospray ionization tandem mass spectrometry.</a> Molecules. 17 (9), 10470-10493 (2012).</li><li>Pang, B., Zhu, Y., Lu, L., Gu, F., Chen, 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+applications+and+features+of+liquid+chromatography-mass+spectrometry+in+the+analysis+of+traditional+Chinese+medicine.">The applications and features of liquid chromatography-mass spectrometry in the analysis of traditional Chinese medicine.</a> Evidence-Based Complementary and Alternative Medicine. 2016, 3837270 (2016).</li><li>Ichou, F., 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=Comparison+of+the+activation+time+effects+and+the+internal+energy+distributions+for+the+CID,+PQD+and+HCD+excitation+modes.">Comparison of the activation time effects and the internal energy distributions for the CID, PQD and HCD excitation modes.</a> Journal of Mass Spectrometry. 49 (6), 498-508 (2014).</li><li>Fu, X., 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=Suppression+of+oligomer+formation+in+glucose+dehydration+by+CO2+and+tetrahydrofuran.">Suppression of oligomer formation in glucose dehydration by CO2 and tetrahydrofuran.</a> Green Chemistry. 19 (14), 3334-3343 (2017).</li><li>Fu, X., 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=Solvent+effects+on+degradative+condensation+side+reactions+of+fructose+in+its+initial+conversion+to+5-Hydroxymethylfurfural.">Solvent effects on degradative condensation side reactions of fructose in its initial conversion to 5-Hydroxymethylfurfural.</a> ChemSusChem. 13 (3), 501-512 (2020).</li><li>Yang, S., Wang, Z., Zhao, H., Ren, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modern+research+of+Tibetan+medicine.">Modern research of Tibetan medicine.</a> World Journal of Traditional Chinese Medicine. 5 (2), 131-138 (2019).</li><li>Shang, X., 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=Ethno-veterinary+survey+of+medicinal+plants+in+Ruoergai+region,+Sichuan+province,+China.">Ethno-veterinary survey of medicinal plants in Ruoergai region, Sichuan province, China.</a> Journal of Ethnopharmacology. 142 (2), 390-400 (2012).</li><li>Su, J., 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=Chalcone+derivatives+from+Abelmoschus+manihot+seeds+restrain+NLRP3+inflammasome+assembly+by+inhibiting+ASC+oligomerization.">Chalcone derivatives from Abelmoschus manihot seeds restrain NLRP3 inflammasome assembly by inhibiting ASC oligomerization.</a> Frontiers in Pharmacology. 13, 932198 (2022).</li><li>Fu, X., 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=Mapping+out+the+reaction+network+of+humin+formation+at+the+initial+stage+of+fructose+dehydration+in+water.">Mapping out the reaction network of humin formation at the initial stage of fructose dehydration in water.</a> Green Energy &amp; Environment. , (2022).</li><li>Hua, Y., Jenke, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increasing+the+sensitivity+of+an+LC-MS+method+for+screening+material+extracts+for+organic+extractables+via+mobile+phase+optimization.">Increasing the sensitivity of an LC-MS method for screening material extracts for organic extractables via mobile phase optimization.</a> Journal of Chromatographic Science. 50 (3), 213-227 (2012).</li><li>Kumar, S., Singh, A., Bajpai, V., Kumar, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+characterization+and+distribution+of+monoterpene+indole+alkaloids+in+Rauwolfia+species+by+Orbitrap+Velos+Pro+mass+spectrometer.">Identification characterization and distribution of monoterpene indole alkaloids in Rauwolfia species by Orbitrap Velos Pro mass spectrometer.</a> Journal of Pharmaceutical and Biomedical Analysis. 118, 183-194 (2016).</li><li>Bayat, P., Lesage, D., Cole, R. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tutorial:+Ion+activation+in+tandem+mass+spectrometry+using+ultra-high+resolution+instrumentation.">Tutorial: Ion activation in tandem mass spectrometry using ultra-high resolution instrumentation.</a> Mass Spectrometry Reviews. 39 (5-6), 680-702 (2020).</li><li>Wu, S. -. L., 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=Mass+spectrometric+determination+of+disulfide+linkages+in+recombinant+therapeutic+proteins+using+online+LC&#8722;MS+with+electron-transfer+dissociation.">Mass spectrometric determination of disulfide linkages in recombinant therapeutic proteins using online LC&#8722;MS with electron-transfer dissociation.</a> Analytical Chemistry. 81 (1), 112-122 (2009).</li><li>Echterbille, J., Quinton, L., Gilles, N., De Pauw, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ion+mobility+mass+spectrometry+as+a+potential+tool+to+assign+disulfide+bonds+arrangements+in+peptides+with+multiple+disulfide+bridges.">Ion mobility mass spectrometry as a potential tool to assign disulfide bonds arrangements in peptides with multiple disulfide bridges.</a> Analytical Chemistry. 85 (9), 4405-4413 (2013).</li></ol>

IT-MS及其MSn 技术为鉴定痕量中药化合物的结构提供了一种新方法。与无法深度识别碎片离子的Q-TOF-MS不同，采用MSn 技术的IT-MS因其分离和积累离子的能力而表现出色。本文概述了一种使用IT-MS和MSn 技术鉴定藏药中痕量化合物的方法。该方法利用MS n中的n 值来确定所提供的碎片离子信息的量。该方法的关键步骤包括选择合适的扫描范围和调整CE值，从而鉴定有价值的?...

中药微量成分的定性分析已成为研究中的重要课题。由于中药中的化合物数量众多，很难将其分离出来用于核磁共振波谱仪（NMR）或X射线衍射仪（XRD）分析，这使得只需要低样品量的质谱（MS）方法越来越受欢迎。此外，液相色谱（LC）与MS联用近年来已广泛应用于中药研究中，用于改进复杂样品的分离和化合物的定性分析1。一种常用的方法是液相色谱-电喷雾电离飞行时间质谱（LC-ESI-TOF-MS），广泛用于藏药的定性研究2。使用这种方法，复杂组分在LC色谱柱中富集和分离，并使用MS检测器观察加合物离子的质荷比（m / z）。搜索串联 MS（MS/MS 或 MS2）数据库是目前使用四极杆飞行时间 （Q-TOF） MS 和 Orbitrap MS3 进行小分子分析中可靠化合物注释的最快方法。然而，数据库质量差和各种异构体的存在阻碍了未知化合物的鉴定。此外，MS/MS数据库提供的信息仅限于4，5，6，7。使用可广泛应用于其他中药的通用方案研究每种中药中的化合物具有重要意义。
IT-MS通过向环形电极施加不同的射频（RF）电压来捕获各种离子8。IT-MS可以按不同的时间顺序进行时间序列多阶段MS扫描，提供成分多阶段MS（MS n）碎片，其中n是产物离子级数9。线性IT-MS被认为是结构识别的最佳选择，因为它可用于顺序MSn 实验10。目标离子可以分离并积累在线性IT-MS 1中。IT-MS中的MSn （n ≥ 3）比Q-TOF-MS中的MS/MS提供更多的片段信息。由于IT-MS不能锁定目标离子及其碎片离子，因此它是阐明未知化合物（包括异构体1）结构的有力工具。MSn 技术已广泛应用于未知蛋白、多肽和多糖的结构分析11，12。MSn 中碎片离子的丰度水平比Q-TOF-MS中的MS/MS提供更多的复杂样品中靶向化合物的分子碎片信息。因此，将MSn 技术应用于中医的结构鉴定至关重要。
藏医药是中医13的重要组成部分，这些药物主要来源于高原地区14发现的动物、植物和矿物质。藏药Abelmoschus manihot种子（AMS）是Abelmoschus manihot（linn.medicus）的种子。AMS 是一种传统草药，用于治疗特应性皮炎、风湿病和麻风病等疾病。它含有查耳酮，具有抗菌，抗真菌，抗癌，抗氧化和抗炎作用15。本研究改进了MS n程序，并开发了一种使用IT-MS和MSn鉴定藏药AMS化合物结构的详细方法。优化了某些MS参数，包括离子模式、扫描范围和碰撞模式，以克服鉴定痕量化合物的问题。本研究旨在促进中药微量化合物的标准化结构鉴定。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Acetonitrile</td>
			<td>Thermo Scientific</td>
			<td>CAS 75-05-8</td>
			<td>LC-MS grade</td>
		</tr>
		<tr>
			<td>Formic Acid</td>
			<td>Knowles</td>
			<td>CAS 64-18-6</td>
			<td>HPLC grade</td>
		</tr>
		<tr>
			<td>Linear ion trap mass spectrometer</td>
			<td>Thermo Scientific</td>
			<td>LTQ XL</td>
			<td></td>
		</tr>
		<tr>
			<td>liquid chromatograph</td>
			<td>Thermo Scientific</td>
			<td>U3000</td>
			<td></td>
		</tr>
		<tr>
			<td>LTQ Tune</td>
			<td>Thermo Scientific</td>
			<td>version 2.8.0</td>
			<td>MS control software</td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Thermo Scientific</td>
			<td>CAS 67-56-1</td>
			<td>LC-MS grade</td>
		</tr>
		<tr>
			<td>Pure water</td>
			<td>Thermo Scientific</td>
			<td>CAS 7732-18-5</td>
			<td>LC-MS grade</td>
		</tr>
		<tr>
			<td>Xcalibur</td>
			<td>Thermo Scientific</td>
			<td>version 2.0</td>
			<td>LC-IT-MS operational software</td>
		</tr>
	</tbody>
</table>

standardized identification of compound structure in tibetan medicine using ion trap mass spectrometry and multiple-stage fragmentation analysis

藏药复杂，含有许多未知化合物，因此对其分子结构的深入研究至关重要。液相色谱-电喷雾电离飞行时间质谱（LC-ESI-TOF-MS）常用于提取藏药;然而，在使用光谱数据库后，仍然存在许多不可预测的未知化合物。本文开发了一种使用离子阱质谱（IT-MS）鉴定藏药成分的通用方法。该方法包括用于样品制备、MS设置、LC预运行、方法建立、MS采集、多阶段MS操作和手动数据分析的标准化和编程方案。采用多阶段碎裂法鉴定藏药 Abelmoschus 种子中的两种代表性化合物，并对典型化合物结构进行了详细分析。此外，本文还讨论了离子模式选择、流动相位调整、扫描范围优化、碰撞能量控制、碰撞模式切换、碎片因素和方法局限性等方面。所开发的标准化分析方法是通用的，可以应用于藏药中的未知化合物。

以玻璃二糖为模型，验证了MSn在正离子模式下的可行性。如图2A所示，纤维二糖[C 12 H22O11]+的ESI-MS（正离子模式）在m / z 365处产生质子化分子[M + H]+。[M+H]+ 在 m/z 365 处的产物离子扫描 （CID-MS/MS） 在 m/z 305 处产生第二个碎片离子（图 2B），并使用 MS3 和 MS4 分析对其进行进一步分析（图 2C...

Watch this Scientific Journal Video about Standardized Identification of Compound Structure in Tibetan Medicine Using Ion Trap Mass Spectrometry and Multiple-Stage Fragmentation Analysis at JoVE.com

Standardized Identification of Compound Structure in Tibetan Medicine Using Ion Trap Mass Spectrometry and Multiple-Stage Fragmentation Analysis

在这里，我们描述了一种通用方案和设计，可用于鉴定藏药中复杂的天然产物制剂（基质）中的痕量和微量成分。

利用离子阱质谱和多级碎裂分析对藏药化合物结构进行标准化鉴定

Tibetan medicines are complex and contain numerous unknown compounds, making in-depth research on their molecular structures crucial. Liquid ...

这种方法可以帮助研究人员分析藏药化合物的结构，尤其是树的成分。它可以为天然药物中化合物含量的定性研究提供见解。该技术的主要优点是在这种情况下获得的化合物结构的准确性高于数据库。该技术可用于膀胱或尿液中代谢中间体的结构分析。首先，藏药Abelmoschus manihot的种子样品制备。准确称取一克AMS，并将其放入装有30毫升80%甲醇的锥形烧瓶中。使用40千赫兹的超声波浴超声仪，在25摄氏度下对混合物进行30分钟的提取。然后，将样品以14， 000g离心五分钟。制备注射器和有机0.22微米微孔膜过滤器，并将上清液过滤到两毫升样品瓶中。打开真空泵的开关后，打开氩气缸的主阀和分压阀，并将压力调节到大约0.3兆帕。然后，打开氮气阀。启动质谱或MS控制软件。单击软件面板中的加热 ESI 源并设置 MS 参数，包括加热器温度、气体流速、正负模式的喷雾电压以及毛细管温度。单击“应用”按钮激活用于液相色谱或LC的离子源，分别使用0.1%甲酸在纯乙腈的水溶液中制备流动相A和B。在将它们分别连接到 A 和 B 流体通道之前，在超声浴超声仪中以 40 千赫兹脱气至少 15 分钟。准备 1：9 体积的甲醇水溶液，然后手动将其填充到泵和注射器的清洁液瓶中。启动LC-MS控制软件后，单击直接控制以打开LC控制面板。在泵模块上以逆时针方向打开吹扫阀。单击更多选项以打开泵设置，并将吹扫参数设置为每分钟 5 毫升，持续三分钟。单击清除以开始去除气泡。完成后，关闭吹扫阀。然后，单击Prime注射器冲洗注射器三个周期，洗涤缓冲液循环冲洗环一个周期，外部洗涤针头洗涤针头一个周期。将样品瓶放入取样器中。单击“仪器设置”打开“方法编辑”窗口，然后单击“新建”创建新的LC-MS仪器方法。为方法建立总运行时间并设置压力限制。方法编辑窗口中的总流速、流动梯度、样品温度、柱温和就绪温度增量。对于 MS 方法，请选择常规 MS 或 MSn 实验类型。输入采集时间、极性、质量范围、分流值数和持续时间的值。单击“保存”将设置配置为仪器方法。单击序列设置以打开序列表，其中输入有关样品类型、文件、名称、路径、样品 ID、仪器方法、位置和进样体积的信息。通过单击“保存”记录序列表，然后实施设置并启动MS采集。要将MS数据加载到数据处理软件中，请在资源管理器中双击原始文件。在基础峰色谱图BPI中，通过单击并拖动鼠标选择曲线或AUC下的最大面积。相应的MS谱图将显示在同一窗口中。选择目标离子进行下一次MS/MS分析。重新打开方法编辑窗口，在MSn设置表中，将目标离子的m/z设置为父质量数列中的小数点后一位。接下来，选择碰撞模式并输入碰撞能量或CE值。设置 MS/MS 扫描范围。单击“保存”以记录 MS 方法，并在序列表中输入新的文件名。单击“开始”按钮以启动 MS/MS 采集。采集完成后，双击资源管理器中的原始文件，将MS / MS原始文件加载到数据处理软件中。鉴定光谱中最强的碎片离子，并在MSn方法列表中输入其m/z值。在 MSn 设置表中，设置 MS3 参数，包括碰撞模式、CE 值和扫描范围。再次单击“保存”以记录 MS 方法，并在序列表中输入新的文件名。单击“开始”以启动 MS3 获取。如前所述，双击资源管理器中的原始文件，将MS3原始文件加载到数据处理软件中，然后重复步骤获取MS4频谱。要分析数据，请双击原始文件以打开从MS到MSn的所有质谱图。 手动计算离子和相应碎片离子之间的m / z差异值。然后，根据MS4结果手动绘制核心结构，并根据m / z差值使用官能团或分子链段导出原始结构。根据MSn中的每个分子结构手动绘制分子切割路径。模型碳水化合物纤维二糖的ESI-MS在阳性模式下在m / z 365处产生蛋白质化分子M H。产物离子扫描或CID MS/MS在m / z 305处产生第二个碎片离子。此外，MS3和MS4分析依次在m/z 254和m/z 185处产生第三和第四碎片离子。MS/MS分析揭示了离子碎裂的顺序，即开环水解、CC裂解和脱水。因此，发现这种方法适用于碳水化合物。使用LC Q-TOF MS对AMS进行的初步定性分析揭示了许多未知化合物的存在。m/z 617处M H离子的阴性MSn分析在m / z 571处产生了第二个碎片离子。MS3分析该碎片离子在m/z 525处通过损失羟乙基作为甲醇对应于32道尔顿和羟基作为水而产生第三个碎片离子，即18道尔顿。MS4分析在m / z 344和273处产生了第四个碎片离子。手动鉴定核心结构揭示了化合物在m/z 617处的分子结构及其在MSn中的切割路径。对另一种未知化合物的M H离子进行了产物离子扫描，揭示了其分子结构和裂解机理。真空泵打开后，等待至少五个小时，以确保实验条件下有足够的真空度。统计分析可用于整理具有相同或相似质荷比的片段。随着质谱溶液的增加，该技术可以帮助研究人员在天然药物中获得新的化合物。

Research

JoVE Journal

Chemistry

Untargeted Metabolomics from Biological Sources Using Ultraperformance Liquid Chromatography-High Resolution Mass Spectrometry (UPLC-HRMS)

Untargeted Metabolomics from Biological Sources Using Ultraperformance Liquid Chromatography-High Resolution Mass Spectrometry UPLC-HRMS

不相关的代谢组学，生物源使用超高效液相色谱 - 高分辨质谱（UPLC-HRMS）

Here we present a workflow to analyze the metabolic profiles for biological samples of interest including; cells, serum, or tissue. The sample is first ...

科研

化学

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

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 ...

Sequencing of Plant Wall Heteroxylans Using Enzymic, Chemical (Methylation) and Physical (Mass Spectrometry, Nuclear Magnetic Resonance) Techniques

Sequencing of Plant Wall Heteroxylans Using Enzymic, Chemical Methylation and Physical Mass Spectrometry, Nuclear Magnetic Resonance Techniques

使用酶法，化学（甲基化）和物理（质谱，核磁共振）技术，植物墙Heteroxylans测序

This protocol describes the specific techniques used for the characterization of reducing end (RE) and internal region glycosyl sequence(s) of ...

Characterization, Quantification and Compound-specific Isotopic Analysis of Pyrogenic Carbon Using Benzene Polycarboxylic Acids (BPCA)

Characterization, Quantification and Compound-specific Isotopic Analysis of Pyrogenic Carbon Using Benzene Polycarboxylic Acids BPCA

表征，气相炭用苯聚羧酸的定量和特定化合物同位素分析（BPCA）

Fire-derived, pyrogenic carbon (PyC), sometimes called black carbon (BC), is the carbonaceous solid residue of biomass and fossil fuel combustion, such as ...

Rapid High-throughput Species Identification of Botanical Material Using Direct Analysis in Real Time High Resolution Mass Spectrometry

植物材料的快速高通量物种鉴定实时高分辨质谱法直接分析

We demonstrate that direct analysis in real time-high resolution mass spectrometry can be used to produce mass spectral profiles of botanical material, ...

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

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 ...

Synthesis and Mass Spectrometry Analysis of Oligo-peptoids

寡 peptoids 的合成及质谱分析

Peptoids are sequence-controlled peptide-mimicking oligomers consisting of N-alkylated glycine units. Among many potential applications, peptoids have ...

Imaging Corrosion at the Metal-Paint Interface Using Time-of-Flight Secondary Ion Mass Spectrometry

利用飞行时二次离子质谱法成像金属颜料界面的腐蚀

Corrosion developed at the paint and aluminum (Al) metal-paint interface of an aluminum alloy is analyzed using time-of-flight secondary ion mass ...

Ion Mobility-Mass Spectrometry Techniques for Determining the Structure and Mechanisms of Metal Ion Recognition and Redox Activity of Metal Binding Oligopeptides