Name: multi-faceted mass spectrometric investigation of neuropeptides in callinectes sapidus
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这项研究得到了美国国家科学基金会（CHE-1710140和CHE-2108223）和美国国立卫生研究院（NIH）通过R01DK071801的支持。AP得到了NIH化学 - 生物学界面培训补助金（T32 GM008505）的部分支持。N.V.Q.得到了美国国立卫生研究院的部分支持，从国家心肺和血液研究所到威斯康星大学麦迪逊分校心血管研究中心（T32 HL007936）的Ruth L. Kirschstein国家研究服务奖。L.L.感谢NIH拨款R56 MH110215，S10RR029531和S10OD025084，以及Vilas杰出成就教授职位和Charles Melbourne Johnson教授职位的资金支持，由威斯康星州校友研究基金会和威斯康星大学麦迪逊分校药学院提供资金。

所描述的所有组织采样均按照威斯康星大学麦迪逊分校的指南进行。
1. 神经肽的LC-ESI-MS分析
<ol><li>神经肽提取和脱盐<ol>
<li>在组织获取之前，制备酸化甲醇（acMeOH）（90：9：1 MeOH：水：乙酸），如16所述。</li>
		<li>从甲壳类动物17 中收集脑组织，并使用镊子立即将每个组织放入含有20μLacMeOH的0.6mL管中。 注意：不同动物和不...

<ol>
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在神经系统中发现的神经肽和内源性肽的准确鉴定，定量和定位对于理解其功能至关重要23，24。质谱是一种强大的技术，可以完成所有这些工作，即使在没有完全测序基因组的生物体中也是如此。该协议通过LC-ESI-和MALDI-MS的组合检测，定量和定位从 C. sapidus 收集的组织中的神经肽的能力得到了证明。
在LC-ESI-MS分析的样品制?...

神经系统是复杂的，需要一个神经元网络来传递整个生物体的信号。神经系统协调感觉信息和生物反应。信号传输中涉及的复杂和复杂的相互作用需要许多不同的信号分子，如神经递质，类固醇和神经肽。由于神经肽是最多样化和最有效的信号分子，在激活对压力和其他刺激的生理反应中起关键作用，因此确定它们在这些生理过程中的特定作用是有趣的。神经肽功能与其氨基酸结构有关，这决定了迁移性，受体相互作用和亲和力1。诸如组织化学之类的技术很重要，因为神经肽可以在组织的不同区域合成，储存和释放，并且电生理学已被用于研究神经肽结构和功能2，3，4，但这些方法受到通量和特异性的限制，以解决神经肽的巨大序列多样性。
质谱（MS）能够对神经肽结构和丰度进行高通量分析。这可以通过不同的MS技术进行，最常见的是液相色谱 - 电喷雾电离MS（LC-ESI-MS）5 和基质辅助激光解吸/电离MS（MALDI-MS）6。利用高精度的质量测量和MS片段化，MS提供了在没有 先验 知识的情况下将氨基酸序列和翻译后修饰（PTM）状态分配给复杂混合物中的神经肽的能力，以帮助确定其功能7，8。除定性信息外，MS还通过无标记定量（LFQ）或基于标记的方法（如同位素或等压标记）实现神经肽的定量信息9。LFQ的主要优点包括其简单性，分析成本低，样品制备步骤减少，可以最大限度地减少样品损失。然而，LFQ的缺点包括仪器时间成本增加，因为它需要多次技术重复来解决运行间变异性的定量误差。这也导致准确量化微小变异的能力下降。基于标记的方法受到的系统变化较小，因为可以使用各种稳定同位素对多个样品进行差异标记，组合成一个样品，并同时通过质谱分析。这也增加了通量，尽管同位素标记可能非常耗时且成本高昂，用于合成或购买。全扫描质谱（MS1）光谱复杂性也随着多重检测的增加而增加，这减少了能够被分割并因此被鉴定的独特神经肽的数量。相反，等压标记不会增加MS1水平的光谱复杂性，尽管它为低丰度分析物（如神经肽）带来了挑战。由于等压定量是在片段离子质谱（MS2）水平上进行的，因此低丰度神经肽可能无法定量，因为可以选择更丰富的基质成分进行片段化，并且选择的那些可能没有足够高的丰度来量化。通过同位素标记，可以对每个鉴定的肽进行定量。
除了鉴定和定量外，MS还可以通过MALDI-MS成像（MALDI-MSI）10获得定位信息。通过在样品表面上对激光进行光栅，可以将MS光谱编译为每个 m / z 值的热图图像。绘制不同区域不同条件下瞬时神经肽信号强度的图谱可以为功能测定11提供有价值的信息。神经肽的定位尤其重要，因为神经肽功能可能因位置12而异。
神经肽在 体内 的丰度低于其它信号分子，例如神经递质，因此需要灵敏的检测方法13。这可以通过去除更高丰度的基质成分来实现，例如脂质11，14。与常见的蛋白质组学工作流程相比，需要对神经肽分析进行其他考虑，主要是因为大多数神经肽组学分析忽略了酶消化。这限制了神经肽数据分析的软件选项，因为大多数都是使用基于蛋白质组学数据和肽检测通知的蛋白质匹配的算法构建的。然而，许多软件如PEAKS15 由于其 从头 测序功能而更适合神经肽分析。从提取方法到MS数据分析，神经肽的分析需要考虑几个因素。
这里描述的方案包括用于样品制备和二甲基同位素标记，数据采集以及通过LC-ESI-MS，MALDI-MS和MALDI-MSI对神经肽进行数据分析的方法。通过来自几个实验的代表性结果，证明了这些方法鉴定，定量和定位来自蓝蟹 Callinectes sapidus的神经肽的效用和能力。为了更好地理解神经系统，通常使用模型系统。许多生物体没有完全测序的基因组，这阻碍了肽水平的全面神经肽发现。为了减轻这一挑战，包括一种用于鉴定新型神经肽和转录组挖掘的协议，以生成没有完整基因组信息的生物体的数据库。这里介绍的所有方案都可以针对任何物种的神经肽样品进行优化，并应用于任何内源性肽的分析。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Chemicals, Reagents, and Consumables</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>2,5-Dihydroxybenzoic acid (DHB) matrix</td>
			<td>Supelco</td>
			<td>39319</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetic acid</td>
			<td>Fisher Chemical</td>
			<td>A38S-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetonitrile Optima LC/MS grade</td>
			<td>Fisher Chemical</td>
			<td>A955-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonium bicarbonate</td>
			<td>Sigma-Aldrich</td>
			<td>9830</td>
			<td></td>
		</tr>
		<tr>
			<td>Borane pyridine</td>
			<td>Sigma-Aldrich</td>
			<td>179752</td>
			<td></td>
		</tr>
		<tr>
			<td>Bruker peptide calibration mix</td>
			<td>Bruker Daltonics</td>
			<td>NC9846988</td>
			<td></td>
		</tr>
		<tr>
			<td>Capillary</td>
			<td>Polymicro</td>
			<td>1068150019</td>
			<td>to make nanoflow column (75 &#181;m inner diameter x 360 &#181;m outer diameter)</td>
		</tr>
		<tr>
			<td>Cryostat cup</td>
			<td>Sigma-Aldrich</td>
			<td>E6032</td>
			<td>any cup or mold should work</td>
		</tr>
		<tr>
			<td>&#160;Microcentrifuge Tubes</td>
			<td>Eppendorf</td>
			<td>30108434</td>
			<td></td>
		</tr>
		<tr>
			<td>Formaldehyde</td>
			<td>Sigma-Aldrich</td>
			<td>252549</td>
			<td></td>
		</tr>
		<tr>
			<td>Formaldehyde - D2</td>
			<td>Sigma-Aldrich</td>
			<td>492620</td>
			<td></td>
		</tr>
		<tr>
			<td>Formic acid Optima LC/MS grade</td>
			<td>Fisher Chemical</td>
			<td>A117-50</td>
			<td></td>
		</tr>
		<tr>
			<td>Gelatin</td>
			<td>Difco</td>
			<td>214340</td>
			<td>place in 37 &#176;C water bath to melt</td>
		</tr>
		<tr>
			<td>Hydrophobic barrier pen</td>
			<td>Vector Labs</td>
			<td>15553953</td>
			<td></td>
		</tr>
		<tr>
			<td>Indium tin oxide (ITO)-coated glass slides</td>
			<td>Delta Technologies</td>
			<td>CB-90IN-S107</td>
			<td>25 mm x 75 mm x 0.8 mm (width x length x thickness)</td>
		</tr>
		<tr>
			<td>LC-MS vials</td>
			<td>Thermo</td>
			<td>TFMSCERT5000-30LVW</td>
			<td></td>
		</tr>
		<tr>
			<td>Methanol Optima LC/MS Grade</td>
			<td>Fisher Chemical</td>
			<td>A456-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Parafilm</td>
			<td>Sigma-Aldrich</td>
			<td>P7793</td>
			<td>Hydrophobic film</td>
		</tr>
		<tr>
			<td>pH-Indicator strips</td>
			<td>Supelco</td>
			<td>109450</td>
			<td></td>
		</tr>
		<tr>
			<td>Red phosphorus clusters</td>
			<td>Sigma-Aldrich</td>
			<td>343242</td>
			<td></td>
		</tr>
		<tr>
			<td>Reversed phase C18 material</td>
			<td>Waters</td>
			<td>186002350</td>
			<td>manually packed into nanoflow column</td>
		</tr>
		<tr>
			<td>Wite-out pen</td>
			<td>BIC</td>
			<td>150810</td>
			<td></td>
		</tr>
		<tr>
			<td>ZipTip</td>
			<td>Millipore</td>
			<td>Z720070</td>
			<td></td>
		</tr>
		<tr>
			<td>Instruments and Tools</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Automatic matrix sprayer system- M5</td>
			<td>HTX Technologies, LLC</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge - 5424 R</td>
			<td>Eppendorf</td>
			<td>05-401-205</td>
			<td></td>
		</tr>
		<tr>
			<td>Cryostat- HM 550</td>
			<td>Thermo Fisher Scientific</td>
			<td>956564A</td>
			<td></td>
		</tr>
		<tr>
			<td>Desiccant</td>
			<td>Drierite</td>
			<td>2088701</td>
			<td></td>
		</tr>
		<tr>
			<td>Forceps</td>
			<td>WPI</td>
			<td>501764</td>
			<td></td>
		</tr>
		<tr>
			<td>MALDI stainless steel target plate</td>
			<td>Bruker Daltonics</td>
			<td>8280781</td>
			<td></td>
		</tr>
		<tr>
			<td>Pipet-Lite XLS</td>
			<td>Rainin</td>
			<td>17014391</td>
			<td>200 &#181;L</td>
		</tr>
		<tr>
			<td>Q Exactive Plus Hybrid Quadrupole-Orbitrap</td>
			<td>Thermo Fisher Scientific</td>
			<td>IQLAAEGAAPFALGMBDK</td>
			<td></td>
		</tr>
		<tr>
			<td>RapifleX MALDI-TOF/TOF</td>
			<td>Bruker Daltonics</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>SpeedVac - SVC100</td>
			<td>Savant</td>
			<td>SVC-100D</td>
			<td></td>
		</tr>
		<tr>
			<td>Ultrasonic Cleaner</td>
			<td>Bransonic</td>
			<td>2510R-MTH</td>
			<td>for sonication</td>
		</tr>
		<tr>
			<td>Ultrasonic homogenizer</td>
			<td>Fisher Scientific</td>
			<td>FB120110</td>
			<td>FB120 Sonic Dismembrator with CL-18 Probe</td>
		</tr>
		<tr>
			<td>Vaccum pump- Alcatel 2008 A</td>
			<td>Ideal Vacuum Products</td>
			<td>P10976</td>
			<td>ultimate pressure = 1 x 10-4 Torr</td>
		</tr>
		<tr>
			<td>Vortex Mixer</td>
			<td>Corning</td>
			<td>6775</td>
			<td></td>
		</tr>
		<tr>
			<td>Water bath (37C) - Isotemp 110</td>
			<td>Fisher Scientific</td>
			<td>15-460-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Data Analysis Software</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Expasy</td>
			<td>https://web.expasy.org/translate/</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>FlexAnalysis</td>
			<td>Bruker Daltonics</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>FlexControl</td>
			<td>Bruker Daltonics</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>FlexImaging</td>
			<td>Bruker Daltonics</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>PEAKS Studio</td>
			<td>Bioinformatics Solutions, Inc.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>SCiLS Lab</td>
			<td>https://scils.de/</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>SignalP 5.0</td>
			<td>https://services.healthtech.dtu.dk/service.php?SignalP-5.0</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>tBLASTn</td>
			<td>http://blast.ncbi.nlm.nih.gov/Blast.cgi?PROGRAM=tblastn&#38;BLAST_ 
			PROGRAMS=tblastn&#38;PAGE_ 
			TYPE=BlastSearch&#38;SHOW_ 
			DEFAULTS=on&#38;LINK_LOC 
			=blasthome</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

multi-faceted mass spectrometric investigation of neuropeptides in callinectes sapidus

神经肽是调节几乎所有生理和行为过程的信号分子，如发育，繁殖，食物摄入和对外部压力源的反应。然而，神经肽的生化机制和完全补充及其功能作用仍然知之甚少。这些内源性肽的表征受到这类信号分子中巨大多样性的阻碍。此外，神经肽在浓度比神经递质低100倍 -1000倍时具有生物活性，并且在突触释放后容易发生酶降解。质谱（MS）是一种高度灵敏的分析工具，无需全面的 先验 知识即可识别，定量和定位分析物。它非常适合全局分析神经肽并帮助发现新型肽。由于这类肽的低丰度和高化学多样性，几种样品制备方法，MS采集参数和数据分析策略已从蛋白质组学技术中改编，以实现最佳的神经肽表征。在这里，描述了使用液相色谱（LC）-MS和基质辅助激光解吸/电离（MALDI）-MS从复杂生物组织中分离神经肽的方法，以进行序列表征，定量和定位。包括从蓝蟹Callinectes sapidus（一种没有全面基因组信息的生物体）制备神经肽数据库的方案。这些工作流程可以适应使用各种仪器研究不同物种中的其他类别的内源性肽。

样品制备和MS分析的工作流程如图 1所示。解剖神经元组织后，进行均质化，提取和脱盐以纯化神经肽样品。如果需要基于同位素标记的定量，则再次标记样品并脱盐。通过LC-MS / MS分析所得样品以进行神经肽鉴定和定量。
通过蛋白质组学软件鉴定的神经肽应具有良好的肽片段化序列覆盖率，然而，这并不是全局定义或标准化的。对于绝对鉴定，每个氨基...

Watch this Scientific Journal Video about Multi-Faceted Mass Spectrometric Investigation of Neuropeptides in Callinectes sapidus at JoVE.com

Multi-Faceted Mass Spectrometric Investigation of Neuropeptides in Callinectes sapidus

神经肽的质谱表征提供序列、定量和定位信息。这种优化的工作流程不仅对神经肽研究有用，而且对其他内源性肽也很有用。此处提供的方案描述了使用 LC-ESI-MS、MALDI-MS 点斑和 MALDI-MS 成像的神经肽的样品制备、MS 采集、MS 分析和神经肽的数据库生成。

卡利内克特氏菌中神经肽的多方面质谱研究

Neuropeptides are signaling molecules that regulate almost all physiological and behavioral processes, such as development, reproduction, food intake, and ...

内源性肽的分析，其比大多数蛋白质小，但比许多消化的肽大，这是一个未被研究的领域。该协议解决了基于质谱的工作流程中的scap。质谱法具有高灵敏度，可用于靶向感兴趣的特定神经肽，或者可以捕获和检测样品中的一系列神经肽。通过质谱法对神经肽表达的定量和定位可以导致肽治疗的发展和各种疾病的神经肽生物标志物的发现。为了开始神经肽提取，从甲壳类动物中收集脑组织，并使用镊子立即将一个组织放入含有20微升酸化甲醇的0.6毫升管中。向样品中加入150微升酸化甲醇。将总声波患者时间设置为24秒，脉冲时间设置为8秒。在超声波均质机上暂停时间至15秒，幅度为50%，并在冰上均质样品。将样品在20， 000 GS下以4摄氏度离心20分钟。用移液器将上清液转移到管中，并在约35摄氏度的真空浓缩器中干燥。对于脱盐，在20微升0.1%甲酸中重建提取的组织样品。涡旋溶液并在室温水浴中超声处理一分钟。将0.5微升样品涂在pH条上，以确认pH值小于4。在4摄氏度和20， 000 GS下离心30秒。在错觉溶液中准备润湿平衡洗涤液。用C18树脂获得10微升脱盐头。将脱盐吸头放在设置为15微升的20微升移液器上。用润湿溶液吸出尖端三次，用等协作溶液吸出三次。在样品中吸出10次，然后在洗涤溶液中洗涤三次，每次洗涤丢弃。通过在每个错觉溶液中抽吸10次以增加乙腈的顺序进行洗脱。在真空浓缩器中干燥所暗示的神经肽。在五微升0.1%甲酸中重建干燥的脱盐神经肽。涡旋溶液并将其在室温水浴中超声处理一分钟。在 2000 GS 下短暂离心。为了发现神经肽和甲壳组织，将三微升的样品滴移液到疏水膜上。直接在样品液滴上移液三微升DHB基质。通过上下移液混合溶液。将一微升样品和基质混合物移液到MALDI不锈钢靶板的孔中，并使用移液器尖端将每个混合物分散到样品孔的边缘。将一微升的一对一口径和基质混合物放入样品附近的孔中。将含有干燥样品斑点的目标板插入MALDI串联飞行时间仪器中。DHB矩阵将激光功率设置为95%，选择自动最佳检测器增益和智能完整样品载体移动模式。在Z上获取200至3， 200 M范围内的MS光谱，并将每个点的多个光谱相加，以提高神经肽信噪比。用明胶填充半个低温恒温杯，并使其在室温下固化。将剩余的液体明胶在37摄氏度的水浴中保温。从动物中收集所需的神经元组织，并使用镊子立即将组织浸入含有去离子水的0.6毫升管中一秒钟。将组织放在固体明胶的顶部，并用液体明胶填充冷冻机杯的其余部分。使用镊子定位组织。将低温恒温杯放在平坦的表面上，用干冰冷冻。对于切片制备，通过将模具切掉，将明胶嵌入的样品从低温恒温器模具中分离出来。通过将一毫升去离子水滴移液到卡盘上，然后将嵌入的组织压到液滴上，将包埋的组织安装到低温恒温器卡盘上。一旦冷冻移液器，在组织周围有更多的去离子水，以进一步将其固定在卡盘上。以一个细胞的近似厚度切片组织。拇指将每个部分安装到铟锡氧化物涂层的载玻片上，方法是将载玻片的一侧靠近该部分，然后将手指放在载玻片的另一侧，以缓慢加热玻璃并使该部分粘附在载玻片上。仅出口从头肽。CSV 来自平均局部置信度分数大于或等于 75 的峰值。在肽列表中搜索已知的序列基序，这些基序指示属于特定神经肽家族的神经肽。选择感兴趣的已知前亲激素氨基酸序列，并使用TB blast N根据数据库搜索查询前亲激素序列。选择目标生物体并将预期阈值算法参数更改为 1000 以包括低分对齐。运行 blast 程序，然后检查结果，在查询序列和受试者序列之间是否具有高同源性分数，从而产生显著的比对。保存包含核苷酸序列的 FASTA 文件。使用 Expasy 翻译工具将前 pro 激素核苷酸序列翻译成 pre pro 激素肽序列。对于callinectes sapidus选择无脊椎动物线粒体作为遗传密码并运行该工具。使用信号P检查肽序列中的信号肽序列和激素前裂解位点.这是神经肽的片段谱，在低片段质量误差中具有100%序列覆盖率，最大限值为0.02道尔顿。这是一种神经肽的光谱，也鉴定出具有100%序列覆盖率，但片段离子数量少，因此鉴定的置信度较低。这些是单个神经肽的提取离子色谱图，该神经肽在两次独立和连续的运行中鉴定出来。即使保留时间略有不同，这仍然可以用于无标记定量，因为时间偏移小于一分钟。这是包含二甲基标记的神经肽的全扫描质谱的一个例子，导致神经肽的轻形式和重形式之间的质量偏移为4.025道尔顿。De Novo测序肽的片段离子质谱显示出良好的片段化覆盖率，其中对每个氨基酸观察到B和/或Y片段离子，质量误差低至0.02道尔顿。这表明观察到属于甲壳类RYMI神经肽家族的内源性肽。左侧显示了接触井雕刻所有边缘的好点示例。右边显示了坏点的例子。在MALDI MS对来自愈伤组织组织神经肽的成像后，获得对应于不同神经肽的各种M对Z值的离子分布图像。针对特定分析类型的萃取溶剂优化至关重要。还要确保完全均质化，并根据需要调整方法。如果未提取，则不会在下游检测到任何内容。该技术可以提供重要神经肽的基础列表，可以作为潜在的生物标志物进一步研究，并在不需要抗体的情况下提供非靶向定位信息。

Research

JoVE Journal

Chemistry

Multi-Faceted Mass Spectrometric Investigation of Neuropeptides in Callinectes sapidus

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

Matrix-assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) Mass Spectrometric Analysis of Intact Proteins Larger than 100 kDa

Matrix-assisted Laser Desorption/Ionization Time of Flight MALDI-TOF Mass Spectrometric Analysis of Intact Proteins Larger than 100 kDa

基质辅助飞行的完整蛋白质（MALDI-TOF）质谱分析激光解吸/电离飞行时间大于100 kDa的

Effectively determining masses of proteins is critical to many biological studies (e.g. for structural biology investigations). Accurate mass ...

Mass Spectrometric Approaches to Study Protein Structure and Interactions in Lyophilized Powders

质谱途径研究蛋白质结构和相互作用的冻干粉

Amide hydrogen/deuterium exchange (ssHDX-MS) and side-chain photolytic labeling (ssPL-MS) followed by mass spectrometric analysis can be valuable for ...

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 ...

HKUST-1 as a Heterogeneous Catalyst for the Synthesis of Vanillin

科大-1作为香兰素的合成的非均相催化剂

Vanillin (4-hydoxy-3-methoxybenzaldehyde) is the main component of the extract of vanilla bean. The natural vanilla scent is a mixture of approximately ...

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 ...

A Two-Step Pyrolysis-Gas Chromatography Method with Mass Spectrometric Detection for Identification of Tattoo Ink Ingredients and Counterfeit Products

一种用于检测纹身油墨成分和假冒产品的两步热解-气相色谱法

Tattoo inks are complex mixtures of ingredients. Each of them possesses different chemical properties which have to be addressed upon chemical analysis. ...

In situ FTIR Spectroscopy as a Tool for Investigation of Gas/Solid Interaction: Water-Enhanced CO2 Adsorption in UiO-66 Metal-Organic Framework

In situ FTIR Spectroscopy as a Tool for Investigation of Gas/Solid Interaction: Water-Enhanced CO2 Adsorption in UiO-66 Metal-Organic Framework

原位FTIR 光谱作为气体/固体相互作用研究工具：UiO-66 金属-有机框架中的水增强 CO2吸附

In situ infrared spectroscopy is an inexpensive, highly sensitive, and selective valuable tool to investigate the interaction of polycrystalline solids ...

Cell-Lineage Guided Mass Spectrometry Proteomics in the Developing (Frog) Embryo

Cell-Lineage Guided Mass Spectrometry Proteomics in the Developing Frog Embryo

发育（青蛙）胚胎中的细胞谱系引导质谱蛋白质组学

Characterization of molecular events as cells give rise to tissues and organs raises a potential to better understand normal development and design ...