这项工作是通过能源科学办公室的美国能源部资助。

1。激光系统<ol><li>使用的激光脉冲由Q开关Nd制备:在1064纳米和在10赫兹的YAG激光操作。 </li><li>聚焦激光脉冲到具有75毫米焦距镜头的样品。 </li><li>收集的等离子体光与光纤对准并放置形成在样品的等离子体附近。 </li><li>使用阶梯光栅摄谱仪/ ICCD进行光谱解析和记录LIBS谱。 </li><li>操作ICCD在使用125的增益两个非门控和门控模式。 </li><li>使用0微秒的时间延迟（T D）在非门控模式和1微秒T D在门控模式。 </li><li>对于这两种模式中，使用的20微秒与3秒曝光（在ICCD相机芯片上集成的等离子体光）的栅极宽度（T B），这将导致在被加入30个人激光照射以产生每个光谱。 </li><li>记录共有5个这样的谱分析的每个样品。 </li><li>使用数字延迟发生器控制的T激光器和ICCD选通脉冲之间IMING。实验设置显示在图1。 </li><li>验证时序用示波器。 </li><li>操作激光以10同时使用非选通和门探测脉冲能量，25，50，和100毫焦耳。 </li><li>持续监控激光能量和调整纠正漂移，如果必要的。 </li><li>安全的代价:的Nd:YAG激光器是第IV类激光器;操作激光时穿戴适当的激光防护镜在任何时候，建立联动房间与房间的门和激光结合14 </li></ol> 2。样品和样品制备<ol><li>使用合成硅酸盐证标准物质与已知元素含量作为样本，这些模仿常见的土样轻微和追踪选定的元素，涵盖了浓度范围内的量。 </li><li>该痕量元素的浓度范围为几个ppm至10,000 ppm。 表1列出了在这里监视的元素，包括用于分析他们的线型和波长。标示为I和II的线型表示中性原子或单电离原子，分别。每个硅酸盐样品的共同碱基组成为SiO 2（72％），的Al 2 O 3（15％），铁2 O 3（4％），为CaMg（CO 3）2（4％），用Na 2 SO 4（ 2.5％），和K 2 SO 4（2.5％）。 </li><li>按样品进用液压机来创建一个平滑的表面，LIBS分析31毫米直径的颗粒。光滑的表面有助于创造与LIBS结果的一致性。 </li><li>用于分析记录每个光谱一个新的样本点。 </li><li>安全考虑:合成硅酸盐样品中含有多种不同浓度的元素，在操作过程中戴手套。 </li></ol> 3。准备校准曲线<ol><li>制备校准曲线的变量在这两个门和非门控检测过测试激光能量范围项元素。 </li><li>通过绘制峰面积或比例电平的峰面积（y-轴）对元素浓度（x轴），使这些曲线。 </li><li>使用线性趋势线拟合校准曲线。 [屏幕快照1] </li><li>使用3σ检测由IUPAC定义计算的检出限。15 [计算1] </li></ol> 4。等离子体温度测定<ol><li>从测量玻尔兹曼地块等离子温度。 </li><li>使用一组的371-408纳米波长之间的铁行的[Fe（I）]用于创建玻尔兹曼曲线为:ln（Iλ/ GA）=-E U / KT - LN（4ρZ/hcN0）（公式1）在那里我是从峰面积确定过渡的强度，λ是波长，A为转移概率，g是过渡的简并，E u是上州的排放，k为玻尔兹曼常数，T是温度，Z是配分函数，h为普朗克常数，c是光速，N 0是总人口的物种。 </li><li>选择具有已知E U，G和A值铁线路。 </li></ol><ul><li>这里使用的铁（I）线是371.99，374.56，382.04，404.58，406.36 nm处。 </li><li>该E U，G和A值可以在这个网站上找到（ <a href="http://physics.nist.gov/PhysRefData/ASD/lines_form.html" target="_blank">http://physics.nist.gov/PhysRefData/ASD/lines_form.html</a> ） </li><li>确保选择的选项，以显示下打成级信息附加标准的"G"。 </li><li>用E k和克的k值。 </li></ul><ol start="4"><li>为了确定对E U温度，情节LN（Iλ/ GA）和一个线性趋势线拟合数据;斜率等于-1/kT 16,17 [屏幕快照2] </li></ol> 5。电子密度的测定<ol><li>为了测量电氮密度，使用全宽在氢线656.5 nm处的半高（FWHM）。 </li><li>采用T D借此数据= 0.5微秒和T B =对ICCD 4.5微秒。 </li><li>测量氢谱线的半高宽。 [屏幕截图3] </li><li>通过计算电子密度:无E = 8.02×10 12 [Δλ1/2 /α1/2 3/2（公式2）其中N e是电子密度，Δλ1/2的测得的半高宽氢线，α1/2是在减少的波长是温度的函数，并且电子密度。在格里姆的附件IIIa受体提供了用于减少波长的值。16-18 </li><li>使用10,000 K的温度下（这是接近等离子体的平均温度）计算的电子密度。 [屏幕截图4] </li></ol> 6。工作了所有的数据使用程序可以确定的峰面积和/或Microsoft Excel

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作者没有任何透露。

当比较非门和门控检测模式，检测限的数据表明，该门控检测模式允许对检测的所有元素，包括那些没有在非选通检测模式下使用更高的激光能量看到的。使用门控的检测，从等离子体的形成初期的高背景没有观察到与背景降低表示元素的排放更好解决。此外，检出限分别为略低使用门控检测。 通常，有计算了能量测试两个门和非门控检测范围类似的检测限。有少数情况下?...

激光诱导击穿光谱（LIBS）是元素分析的简单方法，该方法使用激光产生的火花作为激发源。激光脉冲被聚焦到一个表面上，加热，烧蚀，雾化和电离导致等离子体形成的表面材料。等离子体的光进行分光，并检测和元件用其光谱特征鉴别。如果正确校准，LIBS技术可以提供定量的结果。 LIBS技术可以分析固体，气体和液体很少或无需样品制备。1这些特性使其非常适合在实验室不能进行分析。 目前，LIBS正在研究用于许多不同的应用，特别是那些需要基于场的测量进行定量。1-8这就需要LIBS仪器的发展，使用适于基于场的系统坚固和紧凑的组件。在大多数情况下，该SE组件不会有基于实验室的仪器的全部功能，从而损害的分析性能。 LIBS结果取决于激光脉冲参数等测量条件，包括采样的几何形状，周围的气氛，以及使用门控或不控检测。9-12基于场的激光诱导击穿光谱仪器，要考虑两个重要因素是脉冲能量以及使用门控与非门控检测。这两个因素决定，在很大程度上的成本，尺寸和激光诱导击穿光谱仪的复杂性。是小的，结构坚固，激光器，可以从10〜50毫焦耳为0.3-10赫兹的重复率产生脉冲市售，将是非常有利的使用。因此，重要的是要知道，如果有的话，在检测能力损失将导致从使用这些激光器。的脉冲能量为LIBS一个关键参数，因为它决定了材料的烧蚀和汽化的量和激励炭等离子体的acteristics。此外，利用门控检测可以提高LIBS系统的成本，其结果，必须使用门控和非门控检测，以确定谱和检测能力之间的差异。 最近，进行对比侦测门控非门控检测钢中发现微量元素的研究。该结果表明，在检测限是可比较的，如果不是更好，非门控检测12 LIBS的一个重要特征是，该技术经历物理和化学基质效应。前者的例子是，激光脉冲游更有效地与导电/金属表面比非导电表面13在本研究中，我们想要确定的脉冲能量和时序参数像土壤模拟物的非导电材料的影响。 虽然，现场便携式LIBS工具已开发和使用对于一些应用，还没有被执行更高的能量和门控系统，以利用土壤模拟物较低的能量和非门控系统相比较的检测能力进行全面的研究。本研究着重于激光脉冲能量和时序参数测定复杂基质中痕量元素。激光脉冲能量范围为10至100毫焦耳取得较低和较高的能量之间的比较。还进行过相同的能量范围内使用门控与非门控检测的比较。

<table border="1">
		<tbody>
		 <tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Equipment</td>
		 </tr>
		 <tr>
			<td>Nd:YAG laser</td>
			<td>Continuum</td>
			<td>Surelite II</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Echelle spectrograh/ICCD</td>
			<td>Catalina/Andor</td>
			<td>SE200/iStar</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Digital delay generator</td>
			<td>BNC</td>
			<td>Model 575-4C</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Hydraulic Press</td>
			<td>Carver</td>
			<td>Model-C</td>
			<td></td>
		 </tr>
		 <tr>
			<td>31-mm pellet die</td>
			<td>Carver</td>
			<td>3902</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Power meter indictor model</td>
			<td>Scientech, Inc.</td>
			<td>Model number: AI310D</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Power meter detector model</td>
			<td>Scientech, Inc.</td>
			<td>Model number: AC2501S</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Oscilloscope</td>
			<td>Tektronix</td>
			<td>MSO 4054</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Optical fiber</td>
			<td>Ocean Optics</td>
			<td>QP1000-2-UV-VIS</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Lens kit (this kit contains the 75 mm f.l. lens)</td>
			<td>CVI Optics</td>
			<td>LK-24-C-1064</td>
			<td></td>
		 </tr>
		 <tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Reagent/Material list</td>
		 </tr>
		 <tr>
			<td>Synthetic silicate sample</td>
			<td>Brammer Standard Company</td>
			<td>GBW 07704 </td>
			<td></td>
		 </tr>
		 <tr>
			<td>Synthetic silicate sample</td>
			<td>Brammer Standard Company</td>
			<td>GBW 07705 </td>
			<td></td>
		 </tr>
		 <tr>
			<td>Synthetic silicate sample</td>
			<td>Brammer Standard Company</td>
			<td>GBW 07706</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Synthetic silicate sample</td>
			<td>Brammer Standard Company</td>
			<td>GBW 07708</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Synthetic silicate sample</td>
			<td>Brammer Standard Company</td>
			<td>GBW 07709</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Aluminum caps (for pressing synthetic silicate samples)</td>
			<td>SCP Science</td>
			<td>040-080-001</td>
			<td></td>
		 </tr>
		</tbody>
 </table>

dependence of laser-induced breakdown spectroscopy results on pulse energies and timing parameters using soil simulants

使用合成硅酸盐样品的某些LIBS检测能力较低的脉冲能量（&lt;100毫焦耳）和时序参数的关系进行了研究。这些样品作为模拟物对土壤和包含在一个宽的浓度范围通常存在于土壤轻微和微量元素。在这项研究中，有100校准曲线用不同的脉冲能量和定时参数制备;检测限和灵敏度是从校准曲线来确定。等离子温度采用玻尔兹曼曲线的各种能量和测试的时序参数也是衡量。等离子体的电子密度使用全宽度半最大值的氢线（FWHM）为656.5毫微米以上测试的能量进行了计算。总的来说，结果表明，使用较低的脉冲能量和非选通检测不严重影响分析结果。这些结果是非常相关的设计场并且可随身携带的激光诱导击穿光谱仪器。

合成硅酸盐样品的激光脉冲能量和检测模式对检测能力的影响。LIBS光谱使用门控和非门控检测过的测试的激光脉冲能量范围内的记录。 100校准曲线从这些数据构造来评估所述激光脉冲的能量的效果。校准曲线是通过（1）用下被分析物峰和（2）之比来分析物峰的面积与铁峰在405.58 nm处的面积的面积制备。的铁浓度为样品之间的均匀，因此，它被用作内标。之比来分析物面积与内部标?...

Watch this Scientific Journal Video about Dependence of Laser-induced Breakdown Spectroscopy Results on Pulse Energies and Timing Parameters Using Soil Simulants at JoVE.com

Dependence of Laser-induced Breakdown Spectroscopy Results on Pulse Energies and Timing Parameters Using Soil Simulants

对土壤模拟物LIBS检测功能采用了一系列的脉冲能量和时序参数的测试。校准曲线被用来确定不同的参数的检测限和灵敏度。一般地，结果表明，没有一个显著减少使用较低的脉冲能量和非选通检测的检测能力。

对脉冲能量和时序参数使用土壤仿制品激光诱导击穿光谱结果依赖

The  dependence of some LIBS detection capabilities on lower pulse energies (&lt;100  mJ) and timing parameters were examined using synthetic silicate ...

dependence-laser-induced-breakdown-spectroscopy-results-on-pulse

Research

JoVE Journal

Chemistry

11.3K 次观看.  Alvernia University. 对土壤模拟物LIBS检测功能采用了一系列的脉冲能量和时序参数的测试。校准曲线被用来确定不同的参数的检测限和灵敏度。一般地，结果表明，没有一个显著减少使用较低的脉冲能量和非选通检测的检测能力。 

视频: Dependence of Laser-induced Breakdown Spectroscopy Results on Pulse Energies and Timing Parameters Using Soil Simulants

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

Effectively determining masses of proteins is critical to many biological studies (e.g. for structural biology investigations). Accurate mass determination allows one to evaluate the correctness of protein primary sequences, the presence of mutations and/or post-translational modifications, the possible protein degradation, the sample homogeneity, and the degree of isotope incorporation in case of labelling (e.g. 13C labelling).
Electrospray ionization (ESI) mass spectrometry (MS) is widely used for mass determination of denatured proteins, but its efficiency is affected by the composition of the sample buffer. In particular, the presence of salts, detergents, and contaminants severely undermines the effectiveness of protein analysis by ESI-MS. Matrix-assisted laser desorption/ionization (MALDI) MS is an attractive alternative, due to its salt tolerance and the simplicity of data acquisition and interpretation. Moreover, the mass determination of large heterogeneous proteins (bigger than 100 kDa) is easier by MALDI-MS due to the absence of overlapping high charge state distributions which are present in ESI spectra.
Here we present an accessible approach for analyzing proteins larger than 100 kDa by MALDI-time of flight (TOF). We illustrate the advantages of using a mixture of two matrices (i.e. 2,5-dihydroxybenzoic acid and &#945;-cyano-4-hydroxycinnamic acid) and the utility of the thin layer method as approach for sample deposition. We also discuss the critical role of the matrix and solvent purity, of the standards used for calibration, of the laser energy, and of the acquisition time. Overall, we provide information necessary to a novice for analyzing intact proteins larger than 100 kDa by MALDI-MS.

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

Accurate mass measurement represents an important step during the investigation of proteins. Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) can be used for such determination and its key advantage is the tolerance to salts, detergents and contaminants. Here we illustrate an accessible approach for the analysis of proteins larger than 100 kDa by MALDI-MS.

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 ...

科研

化学

Transport of Surface-modified Carbon Nanotubes through a Soil Column

Carbon nanotubes (CNTs) are widely manufactured nanoparticles, which are being utilized in a number of consumer products, such as sporting goods, electronics and biomedical applications. Due to their accelerating production and use, CNTs constitute a potential environmental risk if they are released to soil and groundwater systems. It is therefore essential to improve the current understanding of environmental fate and transport of CNTs. The transport and retention of CNTs in both natural and artificial media have been reported in literature, but the findings widely vary and are thus not conclusive. There are a number of physical and chemical parameters responsible for variation in retention and transport. In this study, a complete procedure of selected multiwalled carbon nanotubes (MWCNTs) is presented starting from their surface modification to a complete set of laboratory column experiments at critical physical and chemical scenarios. Results indicate that the stability of the commercially available MWCNTs are critical with their attached surface functional group which can also influence the transport and retention of MWCNT through the surrounding medium.

Surface properties of a nanoparticle are important for their interaction with the surrounding medium. Therefore the surface modification of carbon nanotubes can be critical for their transport and retention through porous media. Here, lab scale column experiments are used to understand the possible transport and retention of these nanoparticles.

表面修饰碳纳米管通过土柱运输

Carbon nanotubes (CNTs) are widely manufactured nanoparticles, which are being utilized in a number of consumer products, such as sporting goods, ...

Construction of Models for Nondestructive Prediction of Ingredient Contents in Blueberries by Near-infrared Spectroscopy Based on HPLC Measurements

Nondestructive prediction of ingredient contents of farm products is useful to ship and sell the products with guaranteed qualities. Here, near-infrared spectroscopy is used to predict nondestructively total sugar, total organic acid, and total anthocyanin content in each blueberry. The technique is expected to enable the selection of only delicious blueberries from all harvested ones. The near-infrared absorption spectra of blueberries are measured with the diffuse reflectance mode at the positions not on the calyx. The ingredient contents of a blueberry determined by high-performance liquid chromatography are used to construct models to predict the ingredient contents from observed spectra. Partial least squares regression is used for the construction of the models. It is necessary to properly select the pretreatments for the observed spectra and the wavelength regions of the spectra used for analyses. Validations are necessary for the constructed models to confirm that the ingredient contents are predicted with practical accuracies. Here we present a protocol to construct and validate the models for nondestructive prediction of ingredient contents in blueberries by near-infrared spectroscopy.

We present here a protocol to construct and validate models for nondestructive prediction of total sugar, total organic acid, and total anthocyanin content in individual blueberries by near-infrared spectroscopy.

基于HPLC测量通过近红外光谱对在蓝莓成分的含量无损预测模型的构建

Nondestructive prediction of ingredient contents of farm products is useful to ship and sell the products with guaranteed qualities. Here, near-infrared ...

Original Experimental Approach for Assessing Transport Fuel Stability

The study of fuel oxidation stability is an important issue for the development of future fuels. Diesel and kerosene fuel systems have undergone several technological changes to fulfill environmental and economic requirements. These developments have resulted in increasingly severe operating conditions whose suitability for conventional and alternative fuels needs to be addressed. For example, fatty acid methyl esters (FAMEs) introduced as biodiesel are more prone to oxidation and may lead to deposit formation. Although several methods exist to evaluate fuel stability (induction period, peroxides, acids, and insolubles), no technique allows one to monitor the real-time oxidation mechanism and to measure the formation of oxidation intermediates that may lead to deposit formation. In this article, we developed an advanced oxidation procedure (AOP) based on two existing reactors. This procedure allows the simulation of different oxidation conditions and the monitoring of the oxidation progress by the means of macroscopic parameters, such as total acid number (TAN) and advanced analytical methods like gas chromatography coupled to mass spectrometry (GC-MS) and Fourier Transform Infrared - Attenuated Total Reflection (FTIR-ATR). We successfully applied AOP to gain an in-depth understanding of the oxidation kinetics of a model molecule (methyl oleate) and commercial diesel and biodiesel fuels. These developments represent a key strategy for fuel quality monitoring during logistics and on-board utilization.

Oxidation stability of transport fuels has become a concern for future fuel development. This work presents an original methodology developed by IFP Energies Nouvelles for assessing fuel stability using two different reactors. This methodology was successfully applied to gain an in-depth understanding of the oxidation kinetics and pathways of model molecules and commercial fuels.

评定运输燃料的稳定性原始实验方法

The study of fuel oxidation stability is an important issue for the development of future fuels. Diesel and kerosene fuel systems have undergone several ...

Insights into the Interactions of Amino Acids and Peptides with Inorganic Materials Using Single-Molecule Force Spectroscopy

The interactions between proteins or peptides and inorganic materials lead to several interesting processes. For example, combining proteins with minerals leads to the formation of composite materials with unique properties. In addition, the undesirable process of biofouling is initiated by the adsorption of biomolecules, mainly proteins, on surfaces. This organic layer is an adhesion layer for bacteria and allows them to interact with the surface. Understanding the fundamental forces that govern the interactions at the organic-inorganic interface is therefore important for many areas of research and could lead to the design of new materials for optical, mechanical and biomedical applications. This paper demonstrates a single-molecule force spectroscopy technique that utilizes an AFM to measure the adhesion force between either peptides or amino acids and well-defined inorganic surfaces. This technique involves a protocol for attaching the biomolecule to the AFM tip through a covalent flexible linker and single-molecule force spectroscopy measurements by atomic force microscope. In addition, an analysis of these measurements is included.

Here we present a protocol to measure the force of interactions between a well-defined inorganic surface and either peptides or amino acids by single-molecule force spectroscopy measurements using an atomic force microscope (AFM). The information obtained from the measurement is important to better understand the peptide-inorganic material interphase.

洞察氨基酸和多肽与无机材料的使用相互作用的单分子力谱

The interactions between proteins or peptides and inorganic materials lead to several interesting processes. For example, combining proteins with minerals ...

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

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

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

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

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

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 ...

The MPLEx Protocol for Multi-omic Analyses of Soil Samples

Mass spectrometry (MS)-based integrated metaproteomic, metabolomic, and lipidomic (multi-omic) studies are transforming our ability to understand and characterize microbial communities in environmental and biological systems. These measurements are even enabling enhanced analyses of complex soil microbial communities, which are the most complex microbial systems known to date. Multi-omic analyses, however, do have sample preparation challenges, since separate extractions are typically needed for each omic study, thereby greatly amplifying the preparation time and amount of sample required. To address this limitation, a 3-in-1 method for the simultaneous extraction of metabolites, proteins, and lipids (MPLEx) from the same soil sample was created by adapting a solvent-based approach. This MPLEx protocol has proven to be both simple and robust for many sample types, even when utilized for limited quantities of complex soil samples. The MPLEx method also greatly enabled the rapid multi-omic measurements needed to gain a better understanding of the members of each microbial community, while evaluating the changes taking place upon biological and environmental perturbations.

A protocol is presented for simultaneously extracting metabolites, proteins, and lipids from a single soil sample, allowing reduced sample preparation times and enabling multi-omic mass spectrometry analyses of samples with limited quantities.

土壤样品多涨价可能分析的 MPLEx 协议

Mass spectrometry (MS)-based integrated metaproteomic, metabolomic, and lipidomic (multi-omic) studies are transforming our ability to understand and ...

A New Straightforward Method for Lipophilicity (logP) Measurement using 19F NMR Spectroscopy

Fluorination has become an effective tool to optimize physicochemical properties of bioactive compounds. One of the applications of fluorine introduction is to modulate the lipophilicity of the compound. In our group, we are interested in the study of the impact of fluorination on lipophilicity of aliphatic fluorohydrins and fluorinated carbohydrates. These are not UV-active, resulting in a challenging lipophilicity determination. Here, we present a straightforward method for the measurement of lipophilicity of fluorinated compounds by 19F NMR spectroscopy. This method requires no UV-activity. Accurate solute mass, solvent and aliquot volume are also not required to be measured. Using this method, we measured the lipophilicities of a large number of fluorinated alkanols and carbohydrates.

A New Straightforward Method for Lipophilicity logP Measurement using 19F NMR Spectroscopy

A novel and straightforward variation of the shake-flask method was developed for accurate lipophilicity measurement of fluorinated compounds by 19F NMR spectroscopy.

一种利用19f 核磁共振光谱测定脂质性 (日志 p) 的新方法

Fluorination has become an effective tool to optimize physicochemical properties of bioactive compounds. One of the applications of fluorine introduction ...

Performing Spectroscopy on Plasmonic Nanoparticles with Transmission-Based Nomarski-Type Differential Interference Contrast Microscopy

Differential interference contrast (DIC) microscopy is a powerful imaging tool that is most commonly employed for imaging microscale objects using visible-range light. The purpose of this protocol is to detail a proven method for preparing plasmonic nanoparticle samples and performing single particle spectroscopy on them with DIC microscopy. Several important steps must be followed carefully in order to perform repeatable spectroscopy experiments. First, landmarks can be etched into the sample substrate, which aids in locating the sample surface and in tracking the region of interest during experiments. Next, the substrate must be properly cleaned of debris and contaminants that can otherwise hinder or obscure examination of the sample. Once a sample is properly prepared, the optical path of the microscope must be aligned, using Kohler Illumination. With a standard Nomarski style DIC microscope, rotation of the sample may be necessary, particularly when the plasmonic nanoparticles exhibit orientation-dependent optical properties. Because DIC microscopy has two inherent orthogonal polarization fields, the wavelength-dependent DIC contrast pattern reveals the orientation of rod-shaped plasmonic nanoparticles. Finally, data acquisition and data analyses must be carefully performed. It is common to represent DIC-based spectroscopy data as a contrast value, but it is also possible to present it as intensity data. In this demonstration of DIC for single particle spectroscopy, the focus is on spherical and rod-shaped gold nanoparticles.

The goal of this protocol is to detail a proven approach for the preparation of plasmonic nanoparticle samples and for performing single particle spectroscopy on them with differential interference contrast (DIC) microscopy.