根据DE-AC05-RL01830和FWP-47319合同，美国能源部、科学办公室、基础能源科学办公室、化学科学、生物科学和地球科学催化计划支持对催化剂应用的审查。国家卫生研究所、国家环境卫生科学研究所根据R21ES029778赠款支持对生物医学应用的审查。实验在EMSL（网格.436923.9）进行，EMSL是能源部科学用户设施办公室，由生物和环境研究办公室赞助，位于太平洋西北国家实验室（PNNL）。PNNL 是巴特尔根据 DE-AC05-RL01830 和 FWP-47319 合同为美国能源部运营的多项目国家实验室。

协议分为四个部分，其中规定1）制备系统中使用的任何固体材料或激活或清除不受欢迎的受体物种，2）在NMR转子中添加固体和液体材料，3）在转子中添加气体，4）在光谱仪中进行NMR实验。该过程代表一个典型的序列，但可以修改以适应实验的具体需要。
1. 预处理固体样品
<ol><li>重量大约是 NMR 实验所需的固体样品质量的两倍（对于 7.5 毫米转子，~250 毫克），并将固体样品放入用于处理炉系统材料的石英样品管中，用石英羊毛堵塞管子以保持材料到位。</li>
	<li>通过将管子放入冷却炉并拧紧连接，将隔离阀连接到固体处理 1） 流或 2） 真空系统。</li>
	<li>将石英管端贴在开阔位置的气体隔离阀上。</li>
	<li>开始治疗。<ol>
<li>对于流系统：<ol>
<li>将热电偶贴在管子外部，用耐热材料将其固定到位。</li>
			<li>开始处理气体的流动（例如，N 2 在 100 sccm），以清除固体表面或激活材料。</li>
		</ol>
</li>
		<li>或者，对于真空系统：<ol>
<li>关闭真空系统的隔离阀并启动真空泵。</li>
			<li>当完全真空建立时，非常缓慢地打开隔离阀将真空涂抹在样品上，定期暂停，使系统保持平衡。继续，直到阀门打开。</li>
		</ol>
</li>
	</ol>
</li>
	<li>打开炉子控制器，将温度坡道程序设置为所需的条件（例如，以 5 °C/min 的坡道速率在 4 小时内 300 °C）。</li>
	<li>启动温度程序并让它运行。</li>
	<li>完成后，允许样品冷却到可行的温度。</li>
	<li>关闭温度控制器并停止流量/真空。</li>
	<li>使用隔离阀快速密封样品，以保持所需的样品环境。</li>
	<li>将石英管与处理系统断开，并将管子和封闭的阀门转移到干燥的 N2净化手套箱的安泰坎伯。</li>
	<li>清空并重新填充安泰坎伯至少4次，并将管子转移到手套箱内。</li>
</ol>2. 将固体样品加载到 NMR 转子中
<ol><li>用转子盖称空和干净的高压、高温 NMR 转子。</li>
	<li>将 NMR 转子放在支架中以保持方向性。</li>
	<li>将样品漏斗放入转子孔中。</li>
	<li>从样品管中取出隔离阀，将少量固体材料倒入漏斗中。</li>
	<li>将粉末向下敲入漏斗中，必要时用包装棒轻轻引导粉末进入转子。</li>
	<li>重复逐步添加固体材料，直到达到所需的数量（例如 1/2 转子）。</li>
	<li>将 NMR 转子（和盖子）与样品进行称重，以确定添加的样本数量。</li>
	<li>如果需要，绘制任何液体样品的指定数量，然后用微型注射器缓慢地将液体注入 NMR 转子的中心。</li>
	<li>将盖子放在顶部并逆时针与转子帽位对接以接合转子，使转子和盖之间的 O 形环接合，从而密封转子。请注意，可能需要定期使用新的 O 环以防止泄漏，特别是使用化学磨蚀性混合物或氢气等小气体时。</li>
	<li>称量 NMR 转子以确定添加样本的总质量。</li>
</ol>3. 在所需条件下向 NMR 转子充电，使用所需的化学品
<ol><li>将密封的 NMR 转子放入转子阶段，确保舞台插入的大小与转子大小兼容，并用手拧紧螺母以固定到位。请注意，在此步骤中，支架中转子的紧度将决定盖封的紧度。</li>
	<li>将转子阶段降低到高压暴露装置的下部。</li>
	<li>使用 Allen 扳手将其中一个螺钉 90° 将转子阶段固定到暴露设备的底部。</li>
	<li>将 NMR 加载设备的顶部部分放入底部部分并放在底部部分的顶部，将 NMR 盖位排列到 NMR 转子的盖头顶部，以确保其接合。</li>
	<li>将 2 个夹子放在唇部顶部，暴露装置的上部和下部在上面和下部相遇并将其锁定到位。</li>
	<li>拧紧暴露装置上部顶部的 6 个螺栓，使上部和下部之间的密封表面接合。</li>
	<li>将 NMR 暴露装置的上部连接到煤气管入口和插座。</li>
	<li>将 NMR 暴露装置上部的热电偶连接到温度传感器。</li>
	<li>如有需要，将加热胶带缠绕在燃气管线和暴露装置的上部，以便与相应的控制器进行加热。热板也可以接合。</li>
	<li>确保暴露室插座打开并关闭气源阀，打开真空泵以清除暴露装置和相关线路中的空气。</li>
	<li>用所需的气体或惰性气体清除线路，在真空和大气压力之间循环三次，以确保线路清除空气。</li>
	<li>从 1） 高压输送系统或 2） 流动系统中准备所需的气体组成，以便在指定压力下引入蒸汽。<ol>
<li>用于高压或真空样品制备：<ol>
<li>关闭暴露装置气体出口，设置气体歧管阀，绕过液体喷射管。</li>
			<li>在高压输送系统的高压注射器泵上设置所需的压力。</li>
			<li>打开高压注射器泵上的气源阀门，运行泵上设置的程序，监控暴露装置内部的实际压力。</li>
			<li>当暴露装置内达到所需的压力时，请停止注射器泵并关闭源气阀。</li>
			<li>通过顺时针旋转外部螺杆机制打开 NMR 转子，该机制与内部 NMR 盖位耦合。</li>
			<li>允许所需压力的气体进入 NMR 转子并平衡。</li>
			<li>通过逆时针旋转外部螺杆机制重新塞入 NMR 转子。查看窗口将帮助确定转子何时关闭。</li>
			<li>通过打开暴露装置气体出口阀，缓慢地压低系统。</li>
		</ol>
</li>
		<li>用于流动气体或蒸汽样本制备：<ol>
<li>确保暴露装置气体出口打开，防止压力过大。</li>
			<li>在质量流量控制器上设置所需的气体流速，并开始气流。</li>
			<li>将液体供应线从液体注射器泵连接到气体歧管。</li>
			<li>设置气体歧管阀，使液体注入线能够流动。</li>
			<li>设置液体注射器泵上的液体流速，以达到所需的蒸汽压力，并开始液体注入。</li>
			<li>通过顺时针旋转与内部 NMR 盖位耦合的外部螺钉机制打开 NMR 转子。</li>
			<li>允许系统平衡到 NMR 转子内部所需的气体压力，并通过逆时针旋转外部螺杆机制重新塞入 NMR 转子。查看窗口将帮助确定转子何时关闭。</li>
			<li>停止液体注射器泵喷射并配置阀门以绕过液体喷射管，使泵与系统断开连接。</li>
			<li>停止流动的气体。</li>
		</ol>
</li>
	</ol></li>
	<li>用惰性气体清除系统，以清除任何潜在的有毒或易燃气体。</li>
	<li>停止任何加热，让系统冷却。</li>
	<li>断开任何加热胶带和热电偶。</li>
	<li>断开输气管和出口煤气管道。</li>
	<li>松开暴露装置顶部的 6 个螺栓，以损坏密封件。</li>
	<li>拆开 2 个夹紧部分，并将它们从曝光设备中删除。</li>
	<li>小心地向上和向下抬起上部。</li>
	<li>使用艾伦扳手松开转子阶段，并用螺纹杆绘制。</li>
	<li>松开转子阶段上的螺母，从设备组件中取下转子。</li>
	<li>称量转子，以确保所需的气体量。</li>
</ol>4. 进行 MAS NMR 实验
<ol><li>将 NMR 转子放入 NMR 探头上的 NMR 线圈中。</li>
	<li>将探头举到磁铁孔中并锁定到位。</li>
	<li>使用 MAS 控制框启动样品旋转，并调整到所需的转子旋转速率。</li>
	<li>使用计算机在所需的通道上开始调整/匹配序列。</li>
	<li>调整探头上的调谐/匹配设置，以优化探头电子设备。</li>
	<li>退出计算机上的调谐/匹配序列，并设置所需的实验参数（如脉冲序列、实验阵列、温度等）。</li>
	<li>收集 MAS NMR 数据。</li>
</ol>

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Z., 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=A+large+sample+volume+magic+angle+spinning+nuclear+magnetic+resonance+probe+for+in+situ+investigations+with+constant+flow+of+reactants.">A large sample volume magic angle spinning nuclear magnetic resonance probe for in situ investigations with constant flow of reactants.</a> Physical Chemistry Chemical Physics. 14 (7), 2137-2143 (2012).</li><li>Jiang, Y., 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=In+situ+MAS+NMR-UV/Vis+investigation+of+H-SAPO-34+catalysts+partially+coked+in+the+methanol-to-olefin+conversion+under+continuous-flow+conditions+and+of+their+regeneration.">In situ MAS NMR-UV/Vis investigation of H-SAPO-34 catalysts partially coked in the methanol-to-olefin conversion under continuous-flow conditions and of their regeneration.</a> Microporous and Mesoporous Materials. 105 (1-2), 132-139 (2007).</li><li>Xu, S., Zhang, W., Liu, X., Han, X., Bao, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhanced+In+situ+Continuous-Flow+MAS+NMR+for+Reaction+Kinetics+in+the+Nanocages.">Enhanced In situ Continuous-Flow MAS NMR for Reaction Kinetics in the Nanocages.</a> Journal of the American Chemical Society. 131 (38), 13722-13727 (2009).</li><li>Graham, T. R., 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=In+situ+Al-27+NMR+Spectroscopy+of+Aluminate+in+Sodium+Hydroxide+Solutions+above+and+below+Saturation+with+Respect+to+Gibbsite.">In situ Al-27 NMR Spectroscopy of Aluminate in Sodium Hydroxide Solutions above and below Saturation with Respect to Gibbsite.</a> Inorganic Chemistry. 57 (19), 11864-11873 (2018).</li><li>Zhang, 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=Boehmite+and+Gibbsite+Nanoplates+for+the+Synthesis+of+Advanced+Alumina+Products.">Boehmite and Gibbsite Nanoplates for the Synthesis of Advanced Alumina Products.</a> ACS Applied Nano Materials. 1 (12), 7115-7128 (2018).</li><li>Zhang, 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=Transformation+of+Gibbsite+to+Boehmite+in+Caustic+Aqueous+Solution+at+Hydrothermal+Conditions.">Transformation of Gibbsite to Boehmite in Caustic Aqueous Solution at Hydrothermal Conditions.</a> Crystal Growth &amp; Design. 19 (10), 5557-5567 (2019).</li><li>Hu, J. Z., Jaegers, N. R., Hu, M. Y., Mueller, K. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+situ+and+ex+situ+NMR+for+battery+research.">In situ and ex situ NMR for battery research.</a> Journal of Physics: Condensed Matter. 30 (46), (2018).</li><li>Hu, J. Z., 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=Adsorption+and+Thermal+Decomposition+of+Electrolytes+on+Nanometer+Magnesium+Oxide:+An+in+situ+C-13+MAS+NMR+Study.">Adsorption and Thermal Decomposition of Electrolytes on Nanometer Magnesium Oxide: An in situ C-13 MAS NMR Study.</a> ACS Applied Materials &amp; Interfaces. 11 (42), 38689-38696 (2019).</li></ol>

作者宣布以下相互竞争的经济利益。J.Z.H和他的同事拥有转子设计（US9151813B2）的专利。J.Z.H.、N.R.J.等人已经就暴露装置提出了临时专利申请。

此处概述的 MAS NMR 光谱测量方法代表了进行高温、高压 MAS NMR 的最先进的技术状态。这些方法能够以可靠、可重复的方式观察在真空大气中发生的相互作用，以及从低温（远低于0°C至250°C）。在灵活的化学环境中探测含有固体、液体和气体混合物的系统的能力，使各种兴趣的实验得以进行。
虽然以前的许多努力都集中在低磁场（300 MHz）中相对较大的（7.5毫米）NMR转子的利用...

样品光谱分析是一种分析工具，用于获取有关感兴趣的材料（如化学状态、结构或反应性）的宝贵信息。从简单的角度来看，核磁共振（NMR）是利用强磁场操纵原子核自旋状态以更好地了解感兴趣物种的化学环境的技术之一。核自旋状态是指由旋转核运动引起的磁力矩的相对方向，这是一种带正电荷的粒子。在没有磁场的情况下，核自旋是随机方向的，但在磁场存在的情况下，核自旋优先与处于低能量自旋状态的磁体外部磁场对齐。将自旋状态拆分为离散能量值称为 Zeeman 效应。这些能量水平（ΔE）之间的差额按方程 1 建模： <img alt="Equation 1" src="/files/ftp_upload/61794/61794equ01.jpg"> h是浮力的常数，B0 是外部磁场的强度，γ是原子核的陀螺磁比。这些自旋的化学环境也对这些能量水平施加轻微的扰动。相应频率的无线电波可用于激发核，随着纵向磁化（基于平行和反平行状态的自旋群）的减少，由于自旋获得相干性，核产生横向磁化。当原子核继续在磁场轴上预切时，旋转磁运动产生一个磁场，该磁场也在旋转并产生电场。该字段调节 NMR 检测线圈中的电子，生成 NMR 信号。样品中核化学环境的微小差异会影响线圈中检测到的频率。
对固体样品的NMR分析引入了流体中未发现的复杂性。在流体中，分子以快速的速度下降，平均原子核周围的化学环境。在固体样品中，没有出现这种平均效应，在NMR信号中引入了方向依赖的化学环境和宽广的光谱线。为了减轻这些挑战，一种称为魔角旋转（MAS）的技术被采用1，2。在 MAS NMR 中，样品在 54.7356° 的角度快速旋转（几千赫），外部磁场使用外部旋转机制处理 NMR 的定向依赖（非热带）相互作用。这大大缩小了 NMR 特征，并通过平均化学移位单极、二极相互作用和四极相互作用的定向依赖条件来增强光谱分辨率。两个值得注意的例外确实妨碍了MAS NMR的线路缩小能力。第一种是强同核耦合，有时存在于1H NMR 中，需要高旋转速度 （~70 kHz） 才能去除。然而，高温应用温度的显著升高将通过传授增强的热运动来大大抑制1H同核相互作用，从而大大降低样品旋转率，从而显著提高光谱分辨率。此外，随着技术的不断发展，现在可以制造直径较小的转子，以达到远超5 kHz的旋转速率，这有助于进一步抑制1H同核二极相互作用。第二个例外是自旋超过一半的核的残余二阶四极相互作用，因为只有第一个顺序术语在神奇的角度被消除，留下更复杂的线形，只有更强的外部磁场才能改进。需要强调的是，2D MQMAS技术可以轻易地融入到目前的技术中，从而以与标准MQMAS实验3类似的方式获得真正的同位素化学移位光谱。
MAS NMR 实现了固体材料的详细定性，加强了观测质量。然而，在NMR转子（样品持有人）中以高速率旋转样品的必要性，也给在高温和压力下进行实验带来了挑战，这些实验可能与感兴趣的条件更相关。有时，在对NMR转子相对苛刻的条件下检查材料是可取的。多项工作已成功改造液态NMR技术，进行高温、高压NMR 4、5、6、7：但是，用于固态 MAS NMR 的商用转子盖可能会在高压下从转子中排出，对设备造成重大损坏。通过检查大大增加样品持有人压力的分解反应，可以加剧这种影响。因此，需要新的设计来有效和安全地进行原位NMR实验。例如，转子必须坚持多种品质才能在 MAS NMR 中有效使用，即非磁性、轻量级、耐用性、耐温性、低 NMR 背景材料、可密封性、高强度和耐化学性。转子必须承受的压力相当大。转子不仅要承受样品中所含的压力（例如高压气体），而且设备的旋转还传递离心力，这种离心力对系统总压力有其自身的贡献8，PT，方程 2： <img alt="Equation 2" src="/files/ftp_upload/61794/61794equ02.jpg"> RI 和RO 分别是内转子和外转子半径，ω是每秒半径的旋转频率，P是 样品压力。
已制定多项策略，以解决这些问题。早期的例子类似于火焰密封管10，11，12或聚合物插入13，14，这不足以在高温和压力下延长，精细控制操作。转子设计的迭代由于使用环氧树脂或陶瓷插入物8、15、16的样品体积减少而受制于最高工作温度的限制。最近的一项技术通过在商用转子套管中采用简单的捕捉功能来降低单位生产成本，但相对较少地控制其可操作17的条件。这里采用的设计是一个全氧化锌，洞穴风格的转子袖子磨与螺纹顶部18。盖子也螺纹，以允许安全密封。反向螺纹可防止样品旋转松开氧化锌帽，O 形环构成密封表面。这种转子设计可见图1和类似的转子和说明，使他们已获得专利19。这种策略具有较高的机械强度、耐化学性和耐温性。
这些设计适用于温度和压力至少 250 °C 和 100 bar，受现成的 NMR 探针技术限制温度。与专业的样品制备设备相结合后，它代表了一种真正强大的技术，用于碳固存、催化、储能和生物医学20等影响深远的应用。此类设备包括一种预处理固体材料的方法，以去除不需要的表面物种，如水。这一步骤通常使用熔炉。干盒通常用于将固体样品加载到 NMR 转子中。从那里，转子被转移到一个曝光装置，使转子可以在严格控制的大气层下打开，将所需的气体或混合物装载到转子中。图 2中描绘了这样的设备。

<table>
	<tbody>
		<tr>
			<td>1) Preparation of Solids Samples</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Gas maniforld</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Gas Mass Flow Controllers</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Vacuum Pump</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Tube Furnace</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Temperature Controller</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Thermocouple</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Quartz Tube</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Isolation Valves</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Quartz Wool</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>2) Loading solid samples into the rotor</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Dry glove box</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>High-temperature, high-pressure NMR rotor</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sample funnel</td>
			<td></td>
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		</tr>
		<tr>
			<td>Sample packing rod</td>
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			<td></td>
		</tr>
		<tr>
			<td>Rotor holder</td>
			<td></td>
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		</tr>
		<tr>
			<td>Analytical Balance</td>
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			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Microsyringe</td>
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			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Rotor cap bit</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>3) Addition of gases to the rotor</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>NMR loading chamber</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Rotor stage and appropriately sized inserts</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Vacuum Pump</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Gas maniforld</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Gas Mass Flow Controllers</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Vacuum Pump</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Heating Tape</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Temperature Controller</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Thermocouple</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Allen wrench</td>
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		</tr>
		<tr>
			<td>Threaded rod</td>
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		</tr>
		<tr>
			<td>Wrenchs</td>
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			<td></td>
		</tr>
		<tr>
			<td>Pressure Gauge</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>High-pressure syringe pump</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Liquid syringe pump</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>4) Conducting the NMR experiments</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>MAS NMR probe</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>NMR spectrometer</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Computer to control the spectrometer</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

high-temperature and high-pressure in situ magic angle spinning nuclear magnetic resonance spectroscopy

核磁共振（NMR）光谱是了解分子结构和粘合环境的重要技术。存在一种驱动，即在与感兴趣的化学过程相关的条件下对材料进行定性。为了解决这个问题，已经开发了原位高温、高压 MAS NMR 方法，以便能够观察一系列压力（真空到几百柱）和温度（远低于 0 °C 至 250 °C）的化学相互作用。此外，样品的化学标识可以由固体、液体、气体或三者的混合物组成。该方法集成了全硅NMR转子（MAS NMR的样品持有人），可以使用螺纹帽密封以压缩O环。该转子具有极大的耐化学性、温度兼容性、低NMR背景，可承受高压。这些综合因素使它能够在广泛的系统组合中加以利用，这反过来又允许它在碳固存、催化、材料科学、地球化学和生物学等不同领域使用。这项技术的灵活性使它成为来自众多学科的科学家的一个有吸引力的选择。

NMR 光谱仪的输出采用自由感应衰减 （FID） 的形式，即兴奋旋转在放松回到热力学平衡时发出的时间域信号。这样的FID类似于图3。当 Fourier 从时间域转换为频率域（频率到 PPM 的方程 3，其中差绝对频率和参考值除以 NMR 光谱仪的载体频率）时，它表示 NMR 频谱，每个峰值表示在独特的化学环境中的核（图 3）。 <img alt="Equation 3" src="/files/ftp_upload/61794/6...

Watch this Scientific Journal Video about High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy at JoVE.com

High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy

固体、液体、气体和混合物的分子结构和动力学对不同的科学领域至关重要。高温、高压原位MAS NMR使在严格控制的化学环境中，能够检测混合相系统中成分的化学环境。

高温高压原位魔角旋转核磁共振光谱

Nuclear magnetic resonance (NMR) spectroscopy represents an important technique to understand the structure and bonding environments of molecules. There ...

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5.4K 次观看.  Pacific Northwest National Laboratory. 固体、液体、气体和混合物的分子结构和动力学对不同的科学领域至关重要。高温、高压原位MAS NMR使在严格控制的化学环境中，能够检测混合相系统中成分的化学环境。

视频: High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy

In Situ SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions

Soft landing of mass-selected ions onto surfaces is a powerful approach for the highly-controlled preparation of materials that are inaccessible using conventional synthesis techniques. Coupling soft landing with in situ characterization using secondary ion mass spectrometry (SIMS) and infrared reflection absorption spectroscopy (IRRAS) enables analysis of well-defined surfaces under clean vacuum conditions. The capabilities of three soft-landing instruments constructed in our laboratory are illustrated for the representative system of surface-bound organometallics prepared by soft landing of mass-selected ruthenium tris(bipyridine) dications, [Ru(bpy)3]2+ (bpy = bipyridine), onto carboxylic acid terminated self-assembled monolayer surfaces on gold (COOH-SAMs). In situ time-of-flight (TOF)-SIMS provides insight into the reactivity of the soft-landed ions. In addition, the kinetics of charge reduction, neutralization and desorption occurring on the COOH-SAM both during and after ion soft landing are studied using in situ Fourier transform ion cyclotron resonance (FT-ICR)-SIMS measurements. In situ IRRAS experiments provide insight into how the structure of organic ligands surrounding metal centers is perturbed through immobilization of organometallic ions on COOH-SAM surfaces by soft landing. Collectively, the three instruments provide complementary information about the chemical composition, reactivity and structure of well-defined species supported on surfaces.

In Situ SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions

Soft landing of mass-selected ions onto surfaces is a powerful approach for the highly-controlled preparation of novel materials. Coupled with analysis by in situ secondary ion mass spectrometry (SIMS) and infrared reflection absorption spectroscopy (IRRAS), soft landing provides unprecedented insights into the interactions of well-defined species with surfaces.

在质谱选择离子软着陆准备好定义的表面原位二次离子质谱和红外光谱

Soft landing of mass-selected ions onto surfaces is a powerful approach for the highly-controlled preparation of materials that are inaccessible using ...

科研

化学

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

This protocol describes the specific techniques used for the characterization of reducing end (RE) and internal region glycosyl sequence(s) of heteroxylans. De-starched wheat endosperm cell walls were isolated as an alcohol-insoluble residue (AIR)1 and sequentially extracted with water (W-sol Fr) and 1 M KOH containing 1% NaBH4 (KOH-sol Fr) as described by Ratnayake et al. (2014)2. Two different approaches (see summary in Figure 1) are adopted. In the first, intact W-sol AXs are treated with 2AB to tag the original RE backbone chain sugar residue and then treated with an endoxylanase to generate a mixture of 2AB-labelled RE and internal region reducing oligosaccharides, respectively. In a second approach, the KOH-sol Fr is hydrolyzed with endoxylanase to first generate a mixture of oligosaccharides which are subsequently labelled with 2AB. The enzymically released ((un)tagged) oligosaccharides from both W- and KOH-sol Frs are then methylated and the detailed structural analysis of both the native and methylated oligosaccharides is performed using a combination of MALDI-TOF-MS, RP-HPLC-ESI-QTOF-MS and ESI-MSn. Endoxylanase digested KOH-sol AXs are also characterized by nuclear magnetic resonance (NMR) that also provides information on the anomeric configuration. These techniques can be applied to other classes of polysaccharides using the appropriate endo-hydrolases.

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

This protocol describes the specific techniques used for the structural characterization of reducing end (RE) and internal region glycosyl sequence(s) of heteroxylans by tagging the RE with 2 aminobenzamide prior to enzymatic (endoxylanase) hydrolysis and then analysis of the resultant oligosaccharides using mass spectrometry (MS) and nuclear magnetic resonance (NMR).

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 ...

High Pressure Single Crystal Diffraction at PX^2

In this report we describe detailed procedures for carrying out single crystal X-ray diffraction experiments with a diamond anvil cell (DAC) at the GSECARS 13-BM-C beamline at the Advanced Photon Source. The DAC program at 13-BM-C is part of the Partnership for Extreme Xtallography (PX^2) project. BX-90 type DACs with conical-type diamond anvils and backing plates are recommended for these experiments. The sample chamber should be loaded with noble gas to maintain a hydrostatic pressure environment. The sample is aligned to the rotation center of the diffraction goniometer. The MARCCD area detector is calibrated with a powder diffraction pattern from LaB6. The sample diffraction peaks are analyzed with the ATREX software program, and are then indexed with the RSV software program. RSV is used to refine the UB matrix of the single crystal, and with this information and the peak prediction function, more diffraction peaks can be located. Representative single crystal diffraction data from an omphacite (Ca0.51Na0.48)(Mg0.44Al0.44Fe2+0.14Fe3+0.02)Si2O6 sample were collected. Analysis of the data gave a monoclinic lattice with P2/n space group at 0.35 GPa, and the lattice parameters were found to be: a = 9.496 &#177;0.006 &#197;, b = 8.761 &#177;0.004 &#197;, c = 5.248 &#177;0.001 &#197;, &#946; = 105.06 &#177;0.03&#186;, &#945; = &#947; = 90&#186;.

In this report, we describe detailed procedures for carrying out single crystal X-ray diffraction experiments with a diamond anvil cell at the GSECARS 13-BM-C beamline at the Advanced Photon Source. ATREX and RSV programs are used to analyze the data.

高压单晶衍射PX ^ 2

In this report we describe detailed procedures for carrying out single crystal X-ray diffraction experiments with a diamond anvil cell (DAC) at the ...

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance imaging (MRI). Their purpose is to enhance the relaxation rate of water protons in tissue, thus increasing the MR image contrast and the specificity of the MRI measurements. Current clinically approved contrast agents are low molecular weight molecules that are rapidly cleared from the body. The use of dendrimers as carriers of paramagnetic chelators can play an important role in the future development of more efficient MRI contrast agents. Specifically, the increase in local concentration of the paramagnetic species results in a higher signal contrast. Furthermore, this CA provides a longer tissue retention time due to its high molecular weight and size. Here, we demonstrate a convenient procedure for the preparation of macromolecular MRI contrast agents based on poly(amidoamine) (PAMAM) dendrimers with monomacrocyclic DOTA-type chelators (DOTA &#8211; 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate). The chelating unit was appended by exploiting the reactivity of the isothiocyanate (NCS) group towards the amine surface groups of the PAMAM dendrimer to form thiourea bridges. Dendrimeric products were purified and analyzed by means of nuclear magnetic resonance spectroscopy, mass spectrometry, and elemental analysis. Finally, high resolution MR images were recorded and the signal contrasts obtained from the prepared dendrimeric and the commercially available monomeric agents were compared.

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

This protocol describes the preparation and characterization of a dendrimeric magnetic resonance imaging (MRI) contrast agent that carries cyclen-based macrocyclic chelates coordinating paramagnetic gadolinium ions. In a series of MRI experiments in vitro, this agent produced an amplified MRI signal when compared to the commercially available monomeric analogue.

制备及<em&gt;体外</em&gt;磁共振成像基于树状大分子造影剂的表征

Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance ...

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. They offer new possibilities for the characterization of living systems and are particularly appropriate for detecting, localizing and quantifying the presence of metal oxide nanoparticles both in biological specimens and the environment. Indeed, these techniques all meet relevant requirements in terms of (i) sensitivity (from 1 up to 10 &#181;g.g-1 of dry mass), (ii) micrometer range spatial resolution, and (iii) multi-element detection. Given these characteristics, microbeam chemical element imaging can powerfully complement routine imaging techniques such as optical and fluorescence microscopy. This protocol describes how to perform a nuclear microprobe analysis on cultured cells (U2OS) exposed to titanium dioxide nanoparticles. Cells must grow on and be exposed directly in a specially designed sample holder used on the optical microscope and in the nuclear microprobe analysis stages. Plunge-freeze cryogenic fixation of the samples preserves both the cellular organization and the chemical element distribution. Simultaneous nuclear microprobe analysis (scanning transmission ion microscopy, Rutherford backscattering spectrometry and particle induced X-ray emission) performed on the sample provides information about the cellular density, the local distribution of the chemical elements, as well as the cellular content of nanoparticles. There is a growing need for such analytical tools within biology, especially in the emerging context of Nanotoxicology and Nanomedicine for which our comprehension of the interactions between nanoparticles and biological samples must be deepened. In particular, as nuclear microprobe analysis does not require nanoparticles to be labelled, nanoparticle abundances are quantifiable down to the individual cell level in a cell population, independently of their surface state.

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis

We describe a procedure for the detection of chemical elements present in situ in human cells as well as their in vitro quantification. The method is well-suited to any cell type and is particularly useful for quantitative chemical analyses in single cells following in vitro metal oxide nanoparticles exposure.

原位金属氧化物纳米粒子的核探针检测与单细胞定量研究

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. ...

Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry

A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose of efficiently driving non-equilibrium chemistry is discussed. The advantage of a flowing plasma reactor is that continuous chemical processes can be driven with the flexibility of startup times in the seconds timescale. The plasma approach is generically suitable for conversion/activation of stable molecules such as CO2, N2 and CH4. Here the reduction of CO2 to CO is used as a model system: the complementary diagnostics illustrate how a baseline thermodynamic equilibrium conversion can be exceeded by the intrinsic non-equilibrium from high vibrational excitation. Laser (Rayleigh) scattering is used to measure the reactor temperature and Fourier Transform Infrared Spectroscopy (FTIR) to characterize in situ internal (vibrational) excitation as well as the effluent composition to monitor conversion and selectivity.

This article describes a flowing microwave reactor that is used to drive efficient non-equilibrium chemistry for the application of conversion/activation of stable molecules such as CO2, N2 and CH4. The goal of the procedure described here is to measure the in situ gas temperature and gas conversion.

用于高效高温化学的非平衡微波等离子体

A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose ...

Microfluidic Dry-spinning and Characterization of Regenerated Silk Fibroin Fibers

The protocol demonstrates a method for mimicking the spinning process of silkworm. In the native spinning process, the contracting spinning duct enables the silk proteins to be compact and ordered by shearing and elongation forces. Here, a biomimetic microfluidic channel was designed to mimic the specific geometry of the spinning duct of the silkworm. Regenerated silk fibroin (RSF) spinning doped with high concentration, was extruded through the microchannel to dry-spin fibers at ambient temperature and pressure. In the post-treated process, the as-spun fibers were drawn and stored in ethanol aqueous solution. Synchrotron radiation wide-angle X-ray diffraction (SR-WAXD) technology was used to investigate the microstructure of single RSF fibers, which were fixed to a sample holder with the RSF fiber axis normal to the microbeam of the X-ray. The crystallinity, crystallite size, and crystalline orientation of the fiber were calculated from the WAXD data. The diffraction arcs near the equator of the two-dimensional WAXD pattern indicate that the post-treated RSF fiber has a high orientation degree.

A protocol for the microfluidic spinning and microstructure characterization of regenerated silk fibroin monofilament is presented.

微流控干纺及再生丝素纤维的表征

The protocol demonstrates a method for mimicking the spinning process of silkworm. In the native spinning process, the contracting spinning duct enables ...

A Convenient Method for Extraction and Analysis with High-Pressure Liquid Chromatography of Catecholamine Neurotransmitters and Their Metabolites

The extraction and analysis of catecholamine neurotransmitters in biological fluids is of great importance in assessing nervous system function and related diseases, but their precise measurement is still a challenge. Many protocols have been described for neurotransmitter measurement by a variety of instruments, including high-pressure liquid chromatography (HPLC). However, there are shortcomings, such as complicated operation or hard-to-detect multiple targets, which cannot be avoided, and presently, the dominant analysis technique is still HPLC coupled with sensitive electrochemical or fluorimetric detection, due to its high sensitivity and good selectivity. Here, a detailed protocol is described for the pretreatment and detection of catecholamines with high pressure liquid chromatography with electrochemical detection (HPLC-ECD) in real urine samples of infants, using electrospun composite nanofibers composed of polymeric crown ether with polystyrene as adsorbent, also known as the packed-fiber solid phase extraction (PFSPE) method. We show how urine samples can be easily precleaned by a nanofiber-packed solid phase column, and how the analytes in the sample can be rapidly enriched, desorbed, and detected on an ECD system. PFSPE greatly simplifies the pretreatment procedures for biological samples, allowing for decreased time, expense, and reduction of the loss of targets. 
Overall, this work illustrates a simple and convenient protocol for solid-phase extraction coupled to an HPLC-ECD system for simultaneous determination of three monoamine neurotransmitters (norepinephrine (NE), epinephrine (E), dopamine (DA)) and two of their metabolites (3-methoxy-4-hydroxyphenylglycol (MHPG) and 3,4-dihydroxy-phenylacetic acid (DOPAC)) in infants' urine. The established protocol was applied to assess the differences of urinary catecholamines and their metabolites between high-risk infants with perinatal brain damage and healthy controls. Comparative analysis revealed a significant difference in urinary MHPG between the two groups, indicating that the catecholamine metabolites may be an important candidate marker for early diagnosis of cases at risk for brain damage in infants.

We present a convenient solid-phase extraction coupled to high-pressure liquid chromatography (HPLC) with electrochemical detection (ECD) for simultaneous determination of three monoamine neurotransmitters and two of their metabolites in infants' urine. We also identify the metabolite MHPG as a potential biomarker for the early diagnosis of brain damage for infants.

用高压液相色谱法提取和分析儿茶酚胺神经递质及其代谢物的简便方法

The extraction and analysis of catecholamine neurotransmitters in biological fluids is of great importance in assessing nervous system function and ...

In Situ Lithiated Reference Electrode: Four Electrode Design for In-operando Impedance Spectroscopy

Extending operating voltage of Li-ion batteries results in higher energy output from these devices. High voltages, however, may trigger or accelerate multiple processes responsible for long-term performance decay. Given the complexity of physical processes occurring inside the cell, it is often challenging to achieve a full understanding of the root causes of this performance degradation. This difficulty arises in part from the fact that any electrochemical measurement of a battery will return the combined contributions of all components in the cell. Incorporation of a reference electrode can solve part of the problem, as it allows the electrochemical reactions of the cathode and the anode to be individually probed. A variation in the voltage range experienced by the cathode, for example, can indicate alterations in the pool of cyclable lithium ions in the full-cell. The structural evolution of the many interphases existing in the battery can also be monitored, by measuring the contributions of each electrode to the overall cell impedance. Such wealth of information amplifies the reach of diagnostic analysis in Li-ion batteries and provides valuable input to the optimization of individual cell components. In this work, we introduce the design of a test cell able to accommodate multiple reference electrodes, and present reference electrodes that are appropriate for each specific type of measurement, detailing the assembly process in order to maximize the accuracy of the experimental results.

The incorporation of reference electrodes in a Li-ion battery provides valuable information to elucidate degradation mechanisms at high voltages. In this article, we present a cell design that accommodates multiple reference electrodes, along with the assembly steps to assure maximum accuracy of the data obtained in electrochemical measurements.

原位锂化参考电极: 四原位阻抗谱的电极设计

Extending operating voltage of Li-ion batteries results in higher energy output from these devices. High voltages, however, may trigger or accelerate ...

Characterizing Lewis Pairs Using Titration Coupled with In Situ Infrared Spectroscopy

Lewis acid-activation of carbonyl-containing substrates is a fundamental basis for facilitating transformations in organic chemistry. Historically, characterization of these interactions has been limited to models equivalent to stoichiometric reactions. Here, we report a method utilizing in situ infrared spectroscopy to probe the solution interactions between Lewis acids and carbonyls under synthetically relevant conditions. Using this method, we were able to identify 1:1 complexation between GaCl3 and acetone and a highly ligated complex for FeCl3 and acetone. The impact of this technique on mechanistic understanding is illustrated by application to the mechanism of Lewis acid-mediated carbonyl-olefin metathesis in which we were able to observe competitive binding interactions between substrate carbonyl and product carbonyl with the catalyst.

Here, we present a method for the observation of solution interactions between Lewis acids and bases by employing in situ infrared spectroscopy as a detector for titration under synthetically relevant conditions. By examining solution interactions, this method represents a complement to X-ray crystallography, and provides an alternative to NMR spectroscopy.

使用滴定与原位红外光谱相结合，对刘易斯对进行特征化

Lewis acid-activation of carbonyl-containing substrates is a fundamental basis for facilitating transformations in organic chemistry. Historically, ...