我们承认美国能源部根据合同 DE-EE0005948 提供的资金。该中心的纳米材料和先进的光子源, 两个办公室的科学用户设施, 得到了美国能源部, 科学办公室, 能源科学办公室, 根据合同号。DE-AC02-06CH11357。这一材料是根据国家科学基金会 (nsf) 和能源部 (能源部) 在 NSF CA 号下所支助的工作为基础的。EEC-1041895。视频编辑是由亚利桑那州立大学的 VISLAB 完成的。本材料所表达的任何意见、发现和结论或建议都是作者的观点, 并不一定反映在 NSF 或能源部。T.N. 得到了由国家科学基金会资助的 IGERT-太阳奖学金 (1144616 奖) 的支持。

<ol>
	<li>Geraki, K., Farquharson, M. J., Bradley, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=X-ray+fluorescence+and+energy+dispersive+x-ray+diffraction+for+the+quantification+of+elemental+concentrations+in+breast+tissue.">X-ray fluorescence and energy dispersive x-ray diffraction for the quantification of elemental concentrations in breast tissue.</a> Phys. Med. Biol. 49, 99-110 (2004).</li><li>Paunesku, T., Vogt, S., Maser, J., Lai, B., Woloschak, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=X-ray+fluorescence+microprobe+imaging+in+biology+and+medicine.">X-ray fluorescence microprobe imaging in biology and medicine.</a> J. Cell. Biochem. 99 (6), 1489-1502 (2006).</li><li>Twining, B. 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=Quantifying+Trace+Elements+in+Individual+Aquatic+Protist+Cells+with+a+Synchrotron+X-ray+Fluorescence+Microprobe.">Quantifying Trace Elements in Individual Aquatic Protist Cells with a Synchrotron X-ray Fluorescence Microprobe.</a> Anal. Chem. 75 (15), 3806-3816 (2003).</li><li>de Jonge, M. D., 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=Quantitative+3D+elemental+microtomography+of+Cylotella+meneghiniana+at+400-nm+resolution.">Quantitative 3D elemental microtomography of Cylotella meneghiniana at 400-nm resolution.</a> Proc. Natl. Acad. Sci. 107 (36), 15676-15680 (2010).</li><li>Du&#265;i&#263;, 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=Enhancement+in+statistical+and+image+analysis+for+in+situ+&#181;SXRF+studies+of+elemental+distribution+and+co-localization,+using+Dioscorea+balcanica.">Enhancement in statistical and image analysis for in situ &#181;SXRF studies of elemental distribution and co-localization, using Dioscorea balcanica.</a> J. Synchrotron Rad. 20, 339-346 (2013).</li><li>Kemner, K. M., 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=Elemental+and+Redox+Analysis+of+Single+Bacterial+Cells+by+X-ray+Microbeam+Analysis.">Elemental and Redox Analysis of Single Bacterial Cells by X-ray Microbeam Analysis.</a> Science. 306 (5696), 686-687 (2004).</li><li>Bertoni, M. I., 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=Nanoprobe+X-ray+fluorescence+characterization+of+defects+in+large-area+solar+cells.">Nanoprobe X-ray fluorescence characterization of defects in large-area solar cells.</a> Energy Environ. Sci. 4 (10), 4252-4257 (2011).</li><li>Fenning, D. P., 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=Iron+distribution+in+silicon+after+solar+cell+processing:+Synchrotron+analysis+and+predictive+modeling.">Iron distribution in silicon after solar cell processing: Synchrotron analysis and predictive modeling.</a> Appl. Phys. Lett. 98 (162103), (2011).</li><li>Buonassisi, 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=Quantifying+the+effect+of+metal-rich+precipitates+on+minority+carrier+diffusion+length+in+multicrystalline+silicon+using+synchrotron-based+spectrally+resolved+x-ray+beam+induced+current.">Quantifying the effect of metal-rich precipitates on minority carrier diffusion length in multicrystalline silicon using synchrotron-based spectrally resolved x-ray beam induced current.</a> Appl. Phys. Lett. 87 (044101), (2005).</li><li>Stuckelberger, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Engineering+solar+cells+based+on+correlative+X-ray+microscopy.">Engineering solar cells based on correlative X-ray microscopy.</a> J. Mat. Res. 32 (10), 1825-1854 (2017).</li><li>Streeck, 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=Grazing-incidence+x-ray+fluorescence+analysis+for+non-destructive+determination+of+In+and+Ga+depth+profiles+in+Cu(In,Ga)Se2+absorber+films.">Grazing-incidence x-ray fluorescence analysis for non-destructive determination of In and Ga depth profiles in Cu(In,Ga)Se2 absorber films.</a> Appl. Phys. Lett. 103 (113904), (2013).</li><li>Luo, 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=Spatially+Heterogeneous+Chlorine+Incorporation+in+Organic-Inorganic+Perovskite+Solar+Cells.">Spatially Heterogeneous Chlorine Incorporation in Organic-Inorganic Perovskite Solar Cells.</a> Chem. Mater. 28, 6536-6543 (2016).</li><li>Stuckelberger, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Charge+Collection+in+Hybrid+Perovskite+Solar+Cells:+Relation+to+the+Nanoscale+Elemental+Distribution.">Charge Collection in Hybrid Perovskite Solar Cells: Relation to the Nanoscale Elemental Distribution.</a> IEEE J. Photovolt. 7 (2), 590-597 (2017).</li><li>Vogt, S., Maser, J., Jacobsen, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Data+analysis+for+X-ray+fluorescence+imaging.">Data analysis for X-ray fluorescence imaging.</a> J. Phys. IV France. 104, 617-622 (2003).</li><li>West, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Grain+engineering:+How+nanoscale+inhomogeneities+can+control+charge+collection+in+solar+cells.">Grain engineering: How nanoscale inhomogeneities can control charge collection in solar cells.</a> Nano Energy. 32, 488-493 (2017).</li><li>Krause, M. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atomic+Radiative+and+Radiationless+Yields+for+K+and+L+Shells.">Atomic Radiative and Radiationless Yields for K and L Shells.</a> J. Phys. Chem. Ref. Data. 8 (2), 307-327 (1979).</li><li>Hubbell, J. H., 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+Review,+Bibliography,+and+Tabulation+of+K,L,+and+Higher+Atomic+Shell+X-Ray+Fluorescence+Yields.">A Review, Bibliography, and Tabulation of K,L, and Higher Atomic Shell X-Ray Fluorescence Yields.</a> J. Phys. Chem. Ref. Data. 23 (2), 339-364 (1994).</li><li>Ravel, B., Newville, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ATHENA,+ARTEMIS,+HEPHAESTUS:+data+analysis+for+X-ray+absorption+spectroscopy+using+IFEFFIT.">ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectroscopy using IFEFFIT.</a> J. Synchrotron Rad. 12, 537-541 (2005).</li><li>West, B. M., 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=X-ray+fluorescence+at+nanoscale+resolution+for+multicomponent+layered+structures:+a+solar+cell+case+study.">X-ray fluorescence at nanoscale resolution for multicomponent layered structures: a solar cell case study.</a> J Synchrotron Rad. 24, (2017).</li><li>De Boer, D. K. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calculation+of+X-Ray+Fluorescence+Intensities+from+Bulk+and+Multilayer+Samples.">Calculation of X-Ray Fluorescence Intensities from Bulk and Multilayer Samples.</a> X-Ray Spectrom. 19 (3), 145-154 (1990).</li><li>Lachance, G. R., Claisse, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Quantitative X-ray Fluorescence Analysis: Theory and Application. , (1995).</li><li>Sokaras, D., Karydas, A. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Secondary+Fluorescence+Enhancement+in+Confocal+X-ray+Microscopy+Analysis.">Secondary Fluorescence Enhancement in Confocal X-ray Microscopy Analysis.</a> Anal. Chem. 81 (12), 4946-4954 (2009).</li></ol>

作者没有什么可透露的。

这些数字显示了使用此过程对数据进行拟合的重要性。图 1 (右) 和 2 (底端)显示了一个由适当的管接头产生的代表性结果。如果有一个不够合适的, 积分频谱图像将显着关闭, 结果量化数据将有错误, 虽然这些将很难发现在大多数情况下。对于某些样本类型, 该标准不代表样本中的元素, 特别是由于样本不包含标准中的任何元素, 因此量化仅依赖于对所有元素的推断信息。兴趣.在这样的?...

基于同步辐射的 XRF 已经在多个学科中使用了数十年。例如, 它已被用于生物学上的研究, 如 Geraki et 等, 他们在其中量化微量的金属浓度在癌和非癌性乳腺组织1。更笼统地说, 定量 XRF 已被应用于广泛的生物学研究, 涉及细胞和组织中的金属浓度, 如 Paunesku et . 所述。2. 同样, 研究了海洋原生生物的微量元素3, 4, 甚至微和营养素分布在植物细胞5 内观察到。通过 Kemner et 等进行工作。通过定量 XRF 分析, 6确定了单个细菌细胞在形态学和元素组成上的显著差异。此外, 与本文所揭示的例子特别相关的是, 研究太阳能电池器件的材料科学家利用高分辨率 XRF 研究硅半导体中亚微米金属杂质的存在7,8, 有关元素分布如何影响太阳能设备中的电气性能的相关工作9,10, 通过放牧入射 X 射线识别 CIGS 薄膜太阳能电池的深度依赖性梯度荧光 (GIXRF) 11。
许多研究不仅利用同步辐射 x 射线荧光的高分辨率能力来研究空间分布, 而且还可以定量地绘制数值结论的信息。在许多研究中, 了解与上述空间分布有关的元素浓度是至关重要的。例如, 在 Geraki et al的工作中, 该研究需要量化癌症和非癌性乳腺组织中铁、铜、锌和钾浓度的差异, 以便更好地了解哪些浓度会有害于人体组织1。同样地, 工作由罗et al。利用量化的 XRF 来识别在钙钛矿太阳能电池中合成的少量氯, 并与含有含氯的前体结合使用12。因此, 对于某些需要元素浓度的研究, 适当的量化是必要的和关键的一步。
从 X 射线荧光 (XRF) 测量中定量元素浓度的过程将荧光强度计数转化为质量浓度 (例如µg/cm2)。原始光谱显示能量色散荧光探测器收集的光子的数量作为能量的函数。光谱首先适合, 然后比较标准测量计算量化数据。特别是, 拟合荧光光谱的第一步即使对元素的定性分析也是至关重要的。这是因为在拟合之前, 计数是基于它们的能量作废的, 当样品中包含有类似荧光跃迁的两个元素时, 就成了一个问题。在这种情况下, 计数可能不正确作废, 因而与错误元素关联。
为了准确得出样品中元素相对数量的结论, 通常也需要对 XRF 光谱进行量化。如果没有适当的量化, 将直接比较重元素和轻元素的计数, 忽略捕获剖面的差异、吸收和荧光概率、荧光光子的衰减以及元素的吸收边缘, 从入射能量, 这一切都影响到光子的数量, 击中探测器。因此, 对每张地图的光谱进行拟合, 并将峰值强度与标准进行比较, 这两种方法都是在下面的过程中进行的, 对于准确量化每个元素浓度是至关重要的。
我们演示如何将荧光光子的原始计数转换为每平方厘米 (µg/cm2) 的单位, 首先拟合一个积分谱, 或者在每个测量点或像素上产生的所有单个光谱的汇总频谱。在2D 地图上。这一光谱显示了样本中不同元素的相对强度。某一元素的吸收边缘与入射光束能量的距离影响其荧光峰的强度。一般而言, 两种能量越近, 这些元素产生的强度就越大, 尽管情况并非总是如此。Ref 13中的图4显示了 methylammonium 铅钙钛矿太阳能电池中的多数元素与所产生的强度直接相关的 X 射线光子吸收长度的依赖性。这说明了元素对能量的荧光响应, 表明它不是随着入射能量距离的增加而持续减少, 而是依赖于元素本身。
这种关系的结果是, 元素通道的原始元素浓度可能会出现较高的激发能量接近入射能量, 即使这些元素的真正数量是较低的与其他元素的激发能量更远的事件。因此, 强度的能量依赖性, 以及其他因素, 如荧光率变化, 不同的吸收边缘, 探测器灵敏度, 测量背景等, 是为什么拟合数据是非常重要的, 在绘制之前关于观察到的元素数量的结论。然后, 我们将一个拟合算法应用于积分频谱, 用户可以通过文本文档定义元素和参数。
由 Vogt et创建的算法。14, 利用感兴趣的区域 (ROI) 筛选, 在其中集成了某些元素的峰值区域和主成分分析 (PCA)。首先, PCA 是为了识别非常明显的元素和峰值。这使得噪声与真实信号分离。其次, 确定的原理元件的数值量化, 这是重要的 deconvoluting 不同的元素峰值与相同的励磁能量, 例如重叠的 Au Mα和 P Kα。最后, 通过集成指定区域, ROI 筛选可以应用于数字数据。
为了将计数与元素浓度联系起来, 一个量化良好的参考 (通常称为 "标准") 是在相同的测量条件、几何和能量下测量的, 如所研究的样本。这个标准经常是从德累斯顿 AXO 或从国家标准和技术协会 (NIST)。它们覆盖了各种不同的元素, 并带有列表元素分布。在相同的测量条件下, 对标准计数的感兴趣样本计数的规范化, 为感兴趣样本的元素量化提供了依据。
更具体地说, 地图通过程序已知的标准信息 (如 AXO 和 NIST 标准的情况) 或通过输入到单独文件中的数据来确定标准的元素及其浓度 (在使用的标准不同)。根据这些信息, 该程序将测量设置下标准元素的测量强度与嵌入在地图中的预期浓度联系起来。然后, 它创建一个缩放因子来调整任何偏移量, 并将此缩放因子推断到标准中未包括的所有剩余元素。然后, 缩放系数包括测量设置的偏移量, 以及在映射中提供的与µg/cm2中的原始计数到区域密度的线性转换的信息。
在这里, 我们演示如何利用该程序, 地图, 由美国 Vogt 博士开发, 以量化数据获得从荧光能力的同步辐射在阿贡国家实验室 (这个) 14。用于演示的数据是使用10图1中所示的测量设置在这个2区 ID D 上获取的。该拟合过程也可应用于从其他同步辐射中采集的数据, 但请注意, 这个同步辐射的某些特性嵌入到程序中, 需要更新。

quantifying x-ray fluorescence data using maps

通过将原始光谱与已知标准进行拟合, 对 X 射线荧光 (XRF) 显微图进行量化是评价材料中化学成分和元素分布的关键。基于同步辐射的 XRF 已成为各种研究课题的整体表征技术, 特别是由于其无损性质和高灵敏度。今天, 同步辐射可以在微米以下的空间分辨率下获得荧光数据, 从而对纳米尺度的成分变化进行评估。通过适当的量化, 可以获得深入、高分辨率的元素隔离、化学计量关系和聚类行为的理解。
本文解释了如何使用阿贡国家实验室开发的地图拟合软件, 以量化全2维 XRF 图。我们作为一个例子, 从铜 (in, Ga) Se2太阳能电池, 采取在先进的光子源光束线 2-ID D 在阿贡国家实验室。我们展示了拟合原始数据的标准程序, 演示了如何评估合适的质量并呈现程序生成的典型输出。此外, 我们在这篇手稿中讨论了某些软件限制, 并提出了如何进一步纠正数据准确和代表性的空间解析, 元素浓度的建议。

下面的数字可以看到适当的拟合结果示例。首先, 在图 1中, 直接比较在一个较差的匹配和一个适合于积分谱之间。坏的适合是修复的两个确保没有元素丢失, 例如, 铜, 其中有一个明确的峰值在图 1(左), 但不包括在配合, 并调整 L 和 K 线的分支比率, 以提高准确性。图 2改为显示在管接头前后元素通道之间的?...

Watch this Scientific Journal Video about Quantifying X-Ray Fluorescence Data Using MAPS at JoVE.com

Quantifying X-Ray Fluorescence Data Using MAPS

在这里, 我们演示使用 X 射线荧光拟合软件, 地图, 由阿贡国家实验室创建的荧光显微数据的量化。结果的量化数据有助于了解样本中的元素分布和化学计量比率。

利用地图量化 X 射线荧光数据

The quantification of X-ray fluorescence (XRF) microscopy maps by fitting the raw spectra to a known standard is crucial for evaluating chemical ...

quantifying-x-ray-fluorescence-data-using-maps

Research

JoVE Journal

Chemistry

10.6K 次观看.  Arizona State University. 在这里, 我们演示使用 X 射线荧光拟合软件, 地图, 由阿贡国家实验室创建的荧光显微数据的量化。结果的量化数据有助于了解样本中的元素分布和化学计量比率。

视频: Quantifying X-Ray Fluorescence Data Using MAPS

Preparing Adherent Cells for X-ray Fluorescence Imaging by Chemical Fixation

X-ray fluorescence imaging allows us to non-destructively measure the spatial distribution and concentration of multiple elements simultaneously over large or small sample areas. It has been applied in many areas of science, including materials science, geoscience, studying works of cultural heritage, and in chemical biology. In the case of chemical biology, for example, visualizing the metal distributions within cells allows us to study both naturally-occurring metal ions in the cells, as well as exogenously-introduced metals such as drugs and nanoparticles. Due to the fully hydrated nature of nearly all biological samples, cryo-fixation followed by imaging under cryogenic temperature represents the ideal imaging modality currently available. However, under the circumstances that such a combination is not easily accessible or practical, aldehyde based chemical fixation remains useful and sometimes inevitable. This article describes in as much detail as possible in the preparation of adherent mammalian cells by chemical fixation for X-ray fluorescent imaging.

Here, we present a protocol on how to determine the quantity and distribution of metals in a sample using synchrotron X-ray fluorescence. We focus on adherent cells, and describe the chemical fixation method to prepare this sample. We then describe how to mount and image the sample using synchrotron X-rays.

化学固定准备贴壁细胞的X射线荧光成像

X-ray fluorescence imaging allows us to non-destructively measure the spatial distribution and concentration of multiple elements simultaneously over ...

科研

化学

X-ray Powder Diffraction in Conservation Science: Towards Routine Crystal Structure Determination of Corrosion Products on Heritage Art Objects

The crystal structure determination and refinement process of corrosion products on historic art objects using laboratory high-resolution X-ray powder diffraction (XRPD) is presented in detail via two case studies.
The first material under investigation was sodium copper formate hydroxide oxide hydrate, Cu4Na4O(HCOO)8(OH)2&#8729;4H2O (sample 1) which forms on soda glass/copper alloy composite historic objects (e.g., enamels) in museum collections, exposed to formaldehyde and formic acid emitted from wooden storage cabinets, adhesives, etc. This degradation phenomenon has recently been characterized as &#34;glass induced metal corrosion&#34;.
For the second case study, thecotrichite, Ca3(CH3COO)3Cl(NO3)2&#8729;6H2O (sample 2), was chosen, which is an efflorescent salt forming needlelike crystallites on tiles and limestone objects which are stored in wooden cabinets and display cases. In this case, the wood acts as source for acetic acid which reacts with soluble chloride and nitrate salts from the artifact or its environment.
The knowledge of the geometrical structure helps conservation science to better understand production and decay reactions and to allow for full quantitative analysis in the frequent case of mixtures.

Modern high resolution X-ray powder diffraction (XRPD) in the laboratory is used as an efficient tool to determine crystal structures of long-known corrosion products on historic objects.

X射线粉末衍射在保护科学:迈向文物艺术品腐蚀产物的常规晶体结构测定

The crystal structure determination and refinement process of corrosion products on historic art objects using laboratory high-resolution X-ray powder ...

Time-resolved Photophysical Characterization of Triplet-harvesting Organic Compounds at an Oxygen-free Environment Using an iCCD Camera

Here, we present a sensible method of the acquisition and analysis of time-resolved photoluminescence using an ultrafast iCCD camera. This system enables the acquisition of photoluminescence spectra covering the time regime from nanoseconds up to 0.1 s. This enables us to follow the changes in the intensity (decay) and emission of the spectra over time. Using this method, it is possible to study diverse photophysical phenomena, such as the emission of phosphorescence, and the contributions of prompt and delayed fluorescence in molecules showing thermally activated delayed fluorescence (TADF). Remarkably, all spectra and decays are obtained in a single experiment. This can be done for solids (thin film, powder, crystal) and liquid samples, where the only limitations are the spectral sensitivity of the camera and the excitation wavelength (532 nm, 355 nm, 337 nm, and 266 nm). This technique is, thus, very important when investigating the excited state dynamics in organic emitters for their application in organic light-emitting diodes and other areas where triplet harvesting is of paramount importance. Since triplet states are strongly quenched by oxygen, emitters with efficient TADF luminescence, or those showing room temperature phosphorescence (RTP), must be correctly prepared in order to remove any dissolved oxygen from solutions and films. Otherwise, no long-lived emission will be observed. The method of degassing solid samples as presented in this work is basic and simple, but the degassing of liquid samples creates additional difficulties and is particularly interesting. A method of minimizing solvent loss and changing the sample concentration, while still enabling to remove oxygen in a very efficient and a repeatable manner, is presented in this work.

Here, we present a method of the spectroscopic characterization of organic molecules by means of time-resolved photoluminescence spectroscopy on the nanosecond-to-millisecond timescale in oxygen-free conditions. Methods to efficiently remove oxygen from the samples and, thus, limit luminescence quenching are also described.

利用 iccd 摄像机对无氧环境下的三重收集有机化合物进行光物理表征

Here, we present a sensible method of the acquisition and analysis of time-resolved photoluminescence using an ultrafast iCCD camera. This system enables ...

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds

Cyclic voltammetry (CV) is a technique used in the analysis of organic compounds. When this technique is combined with electron paramagnetic resonance (EPR) or ultraviolet-visible and near-infrared (UV-Vis-NIR) spectroscopies, we obtain useful information such as electron affinity, ionization potential, band-gap energies, the type of charge carriers, and degradation information that can be used to synthesize stable organic electronic devices. In this study, we present electrochemical and spectroelectrochemical methods to analyze the processes occurring in active layers of an organic device as well as the generated charge carriers.

In this article, we describe electrochemical, electron paramagnetic resonance, and ultraviolet-visible and near-infrared spectroelectrochemical methods to analyze organic compounds for application in organic electronics.

利用循环伏安法、紫外-近红外光谱和 EPR 光谱电化学对有机化合物进行分析

Cyclic voltammetry (CV) is a technique used in the analysis of organic compounds. When this technique is combined with electron paramagnetic resonance ...

Obtaining 3D Chemical Maps by Energy Filtered Transmission Electron Microscopy Tomography

Energy filtered transmission electron microscopy tomography (EFTEM tomography) can provide three-dimensional (3D) chemical maps of materials at a nanometric scale. EFTEM tomography can separate chemical elements that are very difficult to distinguish using other imaging techniques. The experimental protocol described here shows how to create 3D chemical maps to understand the chemical distribution and morphology of a material. Sample preparation steps for data segmentation are presented. This protocol permits the 3D distribution analysis of chemical elements in a nanometric sample. However, it should be noted that currently, the 3D chemical maps can only be generated for samples that are not beam sensitive, since the recording of filtered images requires long exposure times to an intense electron beam. The protocol was applied to quantify the chemical distribution of the components of two different heterogeneous catalyst supports. In the first study, the chemical distribution of aluminum and titanium in titania-alumina supports was analyzed. The samples were prepared using the swing-pH method. In the second, the chemical distribution of aluminum and silicon in silica-alumina supports that were prepared using the sol-powder and mechanical mixture methods was examined.

This paper describes a protocol to achieve 3D chemical maps combining energy filtered imaging and electron tomography. The chemical distribution of two catalyst supports formed by elements that are difficult to distinguish by other imaging techniques was studied. Each application consists of mapping overlapped chemical elements - respectively spaced-ionization edges.

通过能量过滤透射电镜成像获得3D 化学图

Energy filtered transmission electron microscopy tomography (EFTEM tomography) can provide three-dimensional (3D) chemical maps of materials at a ...

Microfluidic Chips for In Situ Crystal X-ray Diffraction and In Situ Dynamic Light Scattering for Serial Crystallography

This protocol describes fabricating microfluidic devices with low X-ray background optimized for goniometer based fixed target serial crystallography. The devices are patterned from epoxy glue using soft lithography and are suitable for in situ X-ray diffraction experiments at room temperature. The sample wells are lidded on both sides with polymeric polyimide foil windows that allow diffraction data collection with low X-ray background. This fabrication method is undemanding and inexpensive. After the sourcing of a SU-8 master wafer, all fabrication can be completed outside of a cleanroom in a typical research lab environment. The chip design and fabrication protocol utilize capillary valving to microfluidically split an aqueous reaction into defined nanoliter sized droplets. This loading mechanism avoids the sample loss from channel dead-volume and can easily be performed manually without using pumps or other equipment for fluid actuation. We describe how isolated nanoliter sized drops of protein solution can be monitored in situ by dynamic light scattering to control protein crystal nucleation and growth. After suitable crystals are grown, complete X-ray diffraction datasets can be collected using goniometer based in situ fixed target serial X-ray crystallography at room temperature. The protocol provides custom scripts to process diffraction datasets using a suite of software tools to solve and refine the protein crystal structure. This approach avoids the artefacts possibly induced during cryo-preservation or manual crystal handling in conventional crystallography experiments. We present and compare three protein structures that were solved using small crystals with dimensions of approximately 10-20 &#181;m grown in chip. By crystallizing and diffracting in situ, handling and hence mechanical disturbances of fragile crystals is minimized. The protocol details how to fabricate a custom X-ray transparent microfluidic chip suitable for in situ serial crystallography. As almost every crystal can be used for diffraction data collection, these microfluidic chips are a very efficient crystal delivery method.

Microfluidic Chips for In Situ Crystal X-ray Diffraction and In Situ Dynamic Light Scattering for Serial Crystallography

This protocol describes in detail how to fabricate and operate microfluidic devices for X-ray diffraction data collection at room temperature. Additionally, it describes how to monitor protein crystallization by dynamic light scattering and how to process and analyze obtained diffraction data.

用于原位晶体 x 射线衍射和原位的微流控芯片系列晶体学的动态光散射

This protocol describes fabricating microfluidic devices with low X-ray background optimized for goniometer based fixed target serial crystallography. The ...

Essential Metal Uptake in Gram-negative Bacteria: X-ray Fluorescence, Radioisotopes, and Cell Fractionation

We demonstrate a scalable method for the separation of the bacterial periplasm from the cytoplasm. This method is used to purify periplasmic protein for the purpose of biophysical characterization, and measure substrate transfer between periplasmic and cytoplasmic compartments. By carefully limiting the time that the periplasm is separated from the cytoplasm, the experimenter can extract the protein of interest and assay each compartment individually for substrate without carry-over contamination between compartments. The extracted protein from fractionation can then be further analyzed for three-dimensional structure determination or substrate-binding profiles. Alternatively, this method can be performed after incubation with a radiotracer to determine total percent uptake, as well as distribution of the tracer (and hence metal transport) across different bacterial compartments. Experimentation with a radiotracer can help differentiate between a physiological substrate and artefactual substrate, such as those caused by mismetallation.
X-ray fluorescence can be used to discover the presence or absence of metal incorporation in a sample, as well as measure changes that may occur in metal incorporation as a product of growth conditions, purification conditions, and/or crystallization conditions. X-ray fluorescence also provides a relative measure of abundance for each metal, which can be used to determine the best metal energy absorption peak to use for anomalous X-ray scattering data collection. Radiometal uptake can be used as a method to validate the physiological nature of a substrate detected by X-ray fluorescence, as well as support the discovery of novel substrates.

A protocol for the extraction of a periplasmic transition metal chaperone in the context of its native binding partners, and biophysical characterization of its substrate contents by X-ray fluorescence and radiometal uptake is presented.

革兰氏阴性菌的基本金属摄取: x 射线荧光、放射性同位素和细胞分馏

We demonstrate a scalable method for the separation of the bacterial periplasm from the cytoplasm. This method is used to purify periplasmic protein for ...

Elemental-sensitive Detection of the Chemistry in Batteries through Soft X-ray Absorption Spectroscopy and Resonant Inelastic X-ray Scattering

Energy storage has become more and more a limiting factor of today's sustainable energy applications, including electric vehicles and green electric grid based on volatile solar and wind sources. The pressing demand of developing high-performance electrochemical energy storage solutions, i.e., batteries, relies on both fundamental understanding and practical developments from both the academy and industry. The formidable challenge of developing successful battery technology stems from the different requirements for different energy-storage applications. Energy density, power, stability, safety, and cost parameters all have to be balanced in batteries to meet the requirements of different applications. Therefore, multiple battery technologies based on different materials and mechanisms need to be developed and optimized. Incisive tools that could directly probe the chemical reactions in various battery materials are becoming critical to advance the field beyond its conventional trial-and-error approach. Here, we present detailed protocols for soft X-ray absorption spectroscopy (sXAS), soft X-ray emission spectroscopy (sXES), and resonant inelastic X-ray scattering (RIXS) experiments, which are inherently elemental-sensitive probes of the transition-metal 3d and anion 2p states in battery compounds. We provide the details on the experimental techniques and demonstrations revealing the key chemical states in battery materials through these soft X-ray spectroscopy techniques.

Here, we present a protocol for typical experiments of soft X-ray absorption spectroscopy (sXAS) and resonant inelastic X-ray scattering (RIXS) with applications in battery material studies.

软 x 射线吸收光谱和共振非弹性 x 射线散射法检测电池化学成分的元素敏感度

Energy storage has become more and more a limiting factor of today's sustainable energy applications, including electric vehicles and green electric grid ...

Analysis of Minerals Produced by hFOB 1.19 and Saos-2 Cells Using Transmission Electron Microscopy with Energy Dispersive X-ray Microanalysis

This video presents the use of transmission electron microscopy with energy dispersive X-ray microanalysis (TEM-EDX) to compare the state of minerals in vesicles released by two human bone cell lines: hFOB 1.19 and Saos-2. These cell lines, after treatment with ascorbic acid (AA) and &#946;-glycerophosphate (&#946;-GP), undergo complete osteogenic transdifferentiation from proliferation to mineralization and produce matrix vesicles (MVs) that trigger apatite nucleation in the extracellular matrix (ECM).
Based on Alizarin Red-S (AR-S) staining and analysis of the composition of minerals in cell lysates using ultraviolet (UV) light or in vesicles using TEM imaging followed by EDX quantitation and ion mapping, we can infer that osteosarcoma Saos-2 and osteoblastic hFOB 1.19 cells reveal distinct mineralization profiles. Saos-2 cells mineralize more efficiently than hFOB 1.19 cells and produce larger mineral deposits that are not visible under UV light but are similar to hydroxyapatite (HA) in that they have more Ca and F substitutions.
The results obtained using these techniques allow us to conclude that the process of mineralization differs depending on the cell type. We propose that, at the cellular level, the origin and properties of vesicles predetermine the type of minerals.

We present a protocol to compare the state of minerals in vesicles released by two human bone cell lines: hFOB 1.19 and Saos-2. Their mineralization profiles were analyzed by Alizarin Red-S (AR-S) staining, ultraviolet (UV) light visualization, transmission electron microscopy (TEM) imaging and energy dispersive X-ray microanalysis (EDX).

透射电镜 hFOB 1.19 和 Saos-2 细胞产生的能量色散 X 射线显微分析

This video presents the use of transmission electron microscopy with energy dispersive X-ray microanalysis (TEM-EDX) to compare the state of minerals in ...

Ligand-Mediated Nucleation and Growth of Palladium Metal Nanoparticles

The size, size distribution and stability of colloidal nanoparticles are greatly affected by the presence of capping ligands. Despite the key contribution of capping ligands during the synthesis reaction, their role in regulating the nucleation and growth rates of colloidal nanoparticles is not well understood. In this work, we demonstrate a mechanistic investigation of the role of trioctylphosphine (TOP) in Pd nanoparticles in different solvents (toluene and pyridine) using in situ SAXS and ligand-based kinetic modeling. Our results under different synthetic conditions reveal the overlap of nucleation and growth of Pd nanoparticles during the reaction, which contradicts the LaMer-type nucleation and growth model. The model accounts for the kinetics of Pd-TOP binding for both, the precursor and the particle surface, which is essential to capture the size evolution as well as the concentration of particles in situ. In addition, we illustrate the predictive power of our ligand-based model through designing the synthetic conditions to obtain nanoparticles with desired sizes. The proposed methodology can be applied to other synthesis systems and therefore serves as an effective strategy for predictive synthesis of colloidal nanoparticles.

The main goal of this work is to elucidate the role of capping agents in regulating the size of palladium nanoparticles by combining in situ small angle x-ray scattering (SAXS) and ligand-based kinetic modeling.

配体介导成核与钯金属纳米粒子的生长

The size, size distribution and stability of colloidal nanoparticles are greatly affected by the presence of capping ligands. Despite the key contribution ...