Este trabajo fue apoyado por las Ciencias Naturales e Ingeniería de Investigación de Canadá Equipo, Descubrimiento y Discovery Accelerator subvenciones concedidas a JMBNRB reconoce el apoyo de la Institución Carnegie de programa de becas de postdoctorado Washington. Stephen Elardo también dio las gracias por su ayuda antes de la filmación con la prensa de cilindro y pistón en el Laboratorio de Geofísica.

Los autores no tienen nada que revelar.

Los resultados de los experimentos de inclusión gratuita realizados utilizando los protocolos descritos aquí anteriormente se han comparado con los datos de la literatura en las referencias 29 (Os, Ir, Au), 30 (Re, Au) y 31 (Pt). Pt es muy instructivo para demostrar la utilidad de run-productos-de inclusión gratuita. Para los experimentos dirigidos a baja f O 2, Ertel y col. 48 asignados inclusiones a un origen estable y, por tanto, limita la re...

Acreción Terrestre se cree que han ocurrido como una serie de colisiones entre planetesimales con una composición mayor condrítico, que termina en una fase de gigante impacto cree responsable de la formación de la Luna 1,2. El calentamiento de la proto-Tierra por impactos y la desintegración de los isótopos de vida corta era suficiente para causar una amplia fusión y la formación de un océano de magma o estanques a través del cual densa Fe-ricos se derrite metálicos podrían descender. Al llegar a la base del océano de magma, masas fundidas metálicas encuentran con un límite reológico, parada, y se someten a equilibrio de silicato de metal final antes de eventualmente descendente a través del manto sólido a la creciente núcleo 2. Además la comunicación química entre el metal y las fases de silicato como fusión metálica atraviesa la parte sólida del manto se cree que está excluida debido al gran tamaño y rápido descenso de diapiros metálicos 3. Esta diferenciación primaria de la Tierra en un núcleo metálico y mant silicatole es revelado hoy por ambas observaciones geofísicas y geoquímicas 4-6. Interpretación de estas observaciones para producir condiciones plausibles para el equilibrio-silicato de metal en la base de un océano de magma, sin embargo, requiere una base de datos adecuada de los resultados experimentales. El manto superior primitiva (PUM) es un depósito hipotético que comprende el residuo de silicato de formación de núcleo y su composición, por tanto, refleja el comportamiento de los elementos traza en el equilibrio de metal-silicato. Los elementos traza se distribuyen entre el metal y el silicato se derrite durante la segregación núcleo sobre la base de su afinidad geoquímica. La magnitud de una preferencia elementos para la fase de metal puede ser descrita por el coeficiente de partición de metal-silicato <img alt="Ecuación 1" src="/files/ftp_upload/52725/52725eq1.jpg" /><img alt="Ecuación 2" src="/files/ftp_upload/52725/52725eq2.jpg" /> (1) Dónde <img alt="Ecuación 3" src="/files/ftp_upload/52725/52725eq3.jpg" /> y <img alt="Ecuación 4" src="/files/ftp_upload/52725/52725eq4.jpg" /> denotan la concentración del elemento i en metal y silicato derrito respectivamente. Los valores de <img alt="Ecuación 5" src="/files/ftp_upload/52725/52725eq5.jpg" /> &gt; 1 indican siderophile comportamiento (hierro amante) y los &lt;1 lithophile (rock amante) comportamiento. Las estimaciones de la composición espectáculo PUM que sidérophile elementos se agotan en relación con las condritas 7, normalmente considerados como representativos de la composición mayor de la Tierra 6,8. Este agotamiento es debido al secuestro de elementos siderófilos por el núcleo, y por elementos refractarios su magnitud debe reflejar directamente valores de <img alt="Ecuación 5" src="/files/ftp_upload/52725/52725eq5.jpg" /> . Por lo tanto, los experimentos de laboratorio tratan de determinar los valores de <img alt="Ecuación 5" src="/files/ftp_upload/52725/52725eq5.jpg" /> durante un raESN de la presión (P), temperatura (T) y la fugacidad de oxígeno (O 2 f) las condiciones que son relevantes para la segregación de metal de la base de un océano de magma. Los resultados de estos experimentos pueden usarse entonces para delinear las regiones de P - T - f O 2 espacio que son compatibles con la abundancia PUM de múltiples elementos siderófilos (por ejemplo, 9-11). Las altas presiones y temperaturas correspondientes a un escenario océano de magma se puede recrear en el laboratorio utilizando un pistón de cilindro o de prensa multi-yunque. El aparato de cilindro y pistón proporciona acceso a las condiciones de presión moderada (~ 2 GPa) y alta temperatura (~ 2573 K), pero permite que grandes volúmenes de muestra y una variedad de materiales de cápsula para ser utilizado fácilmente. La tasa de enfriamiento rápido también permite extinción de una gama de composiciones de fusión de silicato a un vaso, lo que simplifica la interpretación de textura de los run-productos.El aparato multi-yunque emplea normalmente volúmenes de muestra más pequeños pero con diseños de montaje adecuados puede alcanzar presiones de hasta ~ 27 GPa y temperaturas de ~ 3000 K. El uso de estos métodos ha permitido que los datos de partición para muchos de los moderadamente y ligeramente siderófilos elementos sean reunidos en una gran gama de P - condiciones T. Las predicciones de la composición PUM basado en estos datos sugieren equilibrio de silicato de metal ocurrió a las condiciones de presión y temperatura promedio en exceso de ~ 29 GPa y 3000 K, respectivamente, aunque los valores exactos dependen del modelo. Con el fin de dar cuenta de la abundancia de elementos sensibles PUM cierta redox (por ejemplo, V, Cr) el 2 también se cree que evolucionar durante la acreción de ~ 4 a 2 unidades logarítmicas por debajo de la impuesta por co-existente hierro y wüstite f O (FeO ) en condiciones PT equivalentes (el tampón de hierro wüstite) 12. Aunque la abundancia de PUM mcualquier elemento siderófilos pueden explicarse por el equilibrio de metal de silicato en la base de un océano de magma profundo, ha resultado difícil evaluar si esta situación también se aplica a los elementos más altamente siderophile (HSE). La afinidad extrema de los HSE para el hierro metálico indicado por baja presión (P ~ 0,1 MPa) y la temperatura (T &lt;1673 K) experimentos sugiere la tierra de silicato debe ser fuertemente empobrecido en estos elementos. Las estimaciones sobre el contenido de HSE para PUM, sin embargo, sólo indican una disminución moderada con respecto a condrita (Figura 1). Una solución comúnmente postulado al exceso HSE evidente es que la Tierra experimentó una tarde-acreción de material condrítico posterior al núcleo de formación de 13. Este material-acretado tarde habría mezclado con el PUM y elevadas concentraciones de HSE, pero tenía un efecto insignificante sobre los elementos más abundantes. Alternativamente, se ha sugerido que la naturaleza extremadamente siderophile de HSE indicado por P baja </em&gt; - Experimentos T no persisten las altas condiciones PT presentes durante núcleo de formación de 14,15. Con el fin de probar estas hipótesis, los experimentos deben llevarse a cabo para determinar la solubilidad y metal-silicato de partición de HSE en condiciones apropiadas. La contaminación de la parte de silicato de encontronazos productos templados en muchos estudios previos sin embargo, ha complicado el análisis previo del producto y oscurecido los verdaderos coeficientes de reparto de HSE entre metal y se derrite silicato. En experimentos de partición, donde los HSE están presentes a niveles de concentración apropiados a la naturaleza, el extremo preferencia de estos elementos para Fe-metálico impide su medición en la masa fundida de silicato. Para sortear este problema, se realizan mediciones de solubilidad en el que la masa fundida de silicato está saturado en el HSE de interés y los valores de <img alt="Ecuación 5" src="/files/ftp_upload/52725/52725eq5.jpg" /> se calculan utilizando el formalismo de Borisov etal., 16. Silicato Templado ejecutar subproductos de experimentos de solubilidad HSE realizadas en condiciones de reducción, sin embargo, a menudo muestran evidencia de contaminación por dispersa HSE ± Fe inclusiones 17. A pesar de la ubicuidad cerca de estas inclusiones en bajo f O 2 experimentos que contienen Pt, Ir, Os, Re y Ru, (por ejemplo, 18 - 27), no es notable variabilidad entre los estudios en su presentación de textura; comparar, por ejemplo, hace referencia a 22 y 26. Aunque se ha demostrado que las inclusiones pueden formar que son una fase estable a las condiciones de ejecución de un experimento 28, esto no impide la formación de inclusiones como se extingue la muestra. La incertidumbre que rodea el origen de inclusiones hace que el tratamiento de los resultados analíticos difícil, y ha dado lugar a la ambigüedad sobre la verdadera solubilidad de HSE en la reducción de silicato se derrita. Run-productos-de inclusión gratuita son necesarios para evaluarque los estudios han adoptado un enfoque analítico que produce concentraciones de HSE disueltos precisos. Un progreso considerable en la supresión de la formación de metal-inclusiones en condiciones reductoras ahora se ha demostrado en experimentos que utilizan un aparato de pistón-cilindro, en el que el diseño de la muestra fue modificado a partir de estudios anteriores, ya sea mediante la adición de Au o Si a los materiales de partida 29-31. La adición de Au o elemental Si a los materiales de partida altera la geometría de la muestra o f O 2 evolución del experimento respectivamente. Estos métodos están destinados a suprimir la formación de la inclusión de metal mediante la alteración de la temporización de HSE in-difusión versus la reducción de la muestra, y se discuten en Bennett et al. 31. A diferencia de algunos intentos anteriores para limpiar la masa fundida de silicato de inclusiones, tales como equilibración asistida mecánicamente y la centrifugación de pistón-cilindro, el presente protocolo puede implementarse sin appar especializadoATUS y es adecuado para experimentos de alta PT. Descrito en detalle aquí es un enfoque basado en pistón-cilindro para determinar la solubilidad de Re, Os, Ir, Ru, Pt y Au en masa fundida de silicato a alta temperatura (&gt; 1873 K), 2 GPa y un f O 2 similar a la de el tampón de hierro wüstite. Aplicación de un diseño experimental similar también puede resultar exitosa en experimentos de HSE en otras presiones, proporcionando las relaciones de fase requeridos, humectantes y relaciones cinéticas persistir las condiciones elegidas. Sin embargo los datos existentes no son suficientes para predecir si nuestro diseño de la muestra tendrá éxito a presiones correspondientes a un océano de magma profundo. También se indica es un enfoque general que se utiliza para determinar el elemento siderophile moderada y ligeramente (MSE y SSE respectivamente) partición utilizando un dispositivo multi-yunque. Ampliación del conjunto de datos inclusión libre para HSE a alta presión es probable que el empleo de métodos múltiples yunque similares. Togéter, estos procedimientos proporcionan un medio para limitar tanto las condiciones de core-segregación y las etapas de acreción terrestre.

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	<tbody>
		<tr>
			<td>G10 Epoxy/Fiberglass Sheet</td>
			<td>Accurate plastics, Inc.</td>
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		<tr>
			<td>Powdered starting materials- -Oxides, metals, carbonates</td>
			<td>Alfa Aesar</td>
			<td>Specific to desired experiment</td>
			<td></td>
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		<tr>
			<td>Castable 2-part MgO ceramic</td>
			<td>Aremco</td>
			<td>Ceramcast - 584</td>
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			<td>C-Type Thermocouple Wire (W26%Re, W5%Re)</td>
			<td>Concept Alloys</td>
			<td>N/A</td>
			<td>~0.25 mm diameter is suitable for most experiments</td>
		</tr>
		<tr>
			<td>Zirconia Cement</td>
			<td>Cotronics; Resbond 940 2-part cement</td>
			<td>N/A</td>
			<td>Use 100 parts powder for every 25 to 28 parts activator</td>
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			<td>Polyvinyl Acetate (PVA) Glue</td>
			<td>e.g Bostik</td>
			<td>N/A</td>
			<td>Often sold as &#39;white glue&#39;</td>
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			<td>Cyanoacrylate Glue</td>
			<td>e.g Krazy Glue/Loctite</td>
			<td>N/A</td>
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			<td>Piston cylinder pressure vessel and WC piston</td>
			<td>Hi-Quality Carbide Tooling Inc.</td>
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			<td>Custom Order</td>
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			<td>Crushable ZrO2 tubes</td>
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			<td>Crushable MgO rods and tubes</td>
			<td>Saint-Gobain</td>
			<td>Custom Order</td>
			<td></td>
		</tr>
		<tr>
			<td>WC cubes for multi-anvil experiments</td>
			<td>Tungaloy</td>
			<td>Custom Order</td>
			<td>Cubes are grade-F WC alloy</td>
		</tr>
		<tr>
			<td>Single hole alumina tube for multi-anvil thermocouple</td>
			<td>Vesuvius McDanel</td>
			<td>AXS071730-04-06</td>
			<td></td>
		</tr>
		<tr>
			<td>4-hole alumina tube for piston cylinder thermocouple</td>
			<td>Vesuvius McDanel</td>
			<td>AXF1159--07-12&#160;</td>
			<td></td>
		</tr>
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			<td>4-hole alumina tube for multi-anvil thermocouple</td>
			<td>Vesuvius McDanel</td>
			<td>AXF1159-04-06</td>
			<td></td>
		</tr>
	</tbody>
</table>

metal-silicate partitioning at high pressure and temperature: experimental methods and a protocol to suppress highly siderophile element inclusions

Estimates of the primitive upper mantle (PUM) composition reveal a depletion in many of the siderophile (iron-loving) elements, thought to result from their extraction to the core during terrestrial accretion. Experiments to investigate the partitioning of these elements between metal and silicate melts suggest that the PUM composition is best matched if metal-silicate equilibrium occurred at high pressures and temperatures, in a deep magma ocean environment. The behavior of the most highly siderophile elements (HSEs) during this process however, has remained enigmatic. Silicate run-products from HSE solubility experiments are commonly contaminated by dispersed metal inclusions that hinder the measurement of element concentrations in the melt. The resulting uncertainty over the true solubility and metal-silicate partitioning of these elements has made it difficult to predict their expected depletion in PUM. Recently, several studies have employed changes to the experimental design used for high pressure and temperature solubility experiments in order to suppress the formation of metal inclusions. The addition of Au (Re, Os, Ir, Ru experiments) or elemental Si (Pt experiments) to the sample acts to alter either the geometry or rate of sample reduction respectively, in order to avoid transient metal oversaturation of the silicate melt. This contribution outlines procedures for using the piston-cylinder and multi-anvil apparatus to conduct solubility and metal-silicate partitioning experiments respectively. A protocol is also described for the synthesis of uncontaminated run-products from HSE solubility experiments in which the oxygen fugacity is similar to that during terrestrial core-formation. Time-resolved LA-ICP-MS spectra are presented as evidence for the absence of metal-inclusions in run-products from earlier studies, and also confirm that the technique may be extended to investigate Ru. Examples are also given of how these data may be applied.

Los siguientes ejemplos y centrar el debate en los experimentos para determinar HSE solubilidad en silicato funde a baja f O 2. Para ejemplos completos de cómo se pueden usar MSE y datos de partición SSE a partir de experimentos multi-yunque para restringir el P - T - f O 2 condiciones de segregación de metal base, se remite al lector a las referencias. 9 - 11 Figura 7B-D muestra la espalda imágenes de electrones dispersos de encon...

Watch this Scientific Journal Video about Metal-silicate Partitioning at High Pressure and Temperature: Experimental Methods and a Protocol to Suppress Highly Siderophile Element Inclusions at JoVE.co

Metal-silicate Partitioning at High Pressure and Temperature: Experimental Methods and a Protocol to Suppress Highly Siderophile Element Inclusions

We present a procedure to determine the metal-silicate partitioning of siderophile elements, emphasizing techniques that suppress the formation of metal inclusions in experiments for the noble metals. The results of these experiments are used to demonstrate the effect of core-formation on the highly siderophile element composition of the mantle.

-Metal silicato de particionamiento a alta presión y temperatura: Métodos experimentales y un Protocolo para Reprimir altamente sidérophile Element Inclusiones

Estimates of the primitive upper mantle (PUM) composition reveal a depletion in many of the siderophile (iron-loving) elements, thought to result from ...

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12.4K vistas.  University of Toronto. We present a procedure to determine the metal-silicate partitioning of siderophile elements, emphasizing techniques that suppress the formation of metal inclusions in experiments for the noble metals. The results of these experiments are used to demonstrate the effect of core-formation on the highly siderophile element composition of the mantle.

Video: Metal-silicate Partitioning at High Pressure and Temperature: Experimental Methods and a Protocol to Suppress Highly Siderophile Element Inclusions

High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems

The high pressure sapphire cell apparatus was constructed to visually determine the composition of multiphase systems without physical sampling. Specifically, the sapphire cell enables visual data collection from multiple loadings to solve a set of material balances to precisely determine phase composition. Ternary phase diagrams can then be established to determine the proportion of each component in each phase at a given condition. In principle, any ternary system can be studied although ternary systems (gas-liquid-liquid) are the specific examples discussed herein. For instance, the ternary THF-Water-CO2 system was studied at 25 and 40&#160;&#176;C and is described herein. Of key importance, this technique does not require sampling. Circumventing the possible disturbance of the system equilibrium upon sampling, inherent measurement errors, and technical difficulties of physically sampling under pressure is a significant benefit of this technique. Perhaps as important, the sapphire cell also enables the direct visual observation of the phase behavior. In fact, as the CO2 pressure is increased, the homogeneous THF-Water solution phase splits at about 2 MPa. With this technique, it was possible to easily and clearly observe the cloud point and determine the composition of the newly formed phases as a function of pressure.
The data acquired with the sapphire cell technique can be used for many applications. In our case, we measured swelling and composition for tunable solvents, like gas-expanded liquids, gas-expanded ionic liquids and Organic Aqueous Tunable Systems (OATS)1-4. For the latest system, OATS, the high-pressure sapphire cell enabled the study of (1) phase behavior as a function of pressure and temperature, (2) composition of each phase (gas-liquid-liquid) as a function of pressure and temperature and (3) catalyst partitioning in the two liquid phases as a function of pressure and composition. Finally, the sapphire cell is an especially effective tool to gather accurate and reproducible measurements in a timely fashion.

High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems

The high pressure sapphire cell apparatus is a unique tool to study, without sampling, phase behavior under a wide range of pressures. Using a cathetometer, very precise volume measurements can be recorded to measure liquid expansion and phase composition. Thus, this synthetic method enables the study of (1) phase equilibria of multi-component mixtures and (2) the partition behavior of catalyst or model compounds as a function of pressure.

De alta presión de la célula de zafiro para la Fase Equilibrios mediciones de CO<sub&gt; 2</sub&gt; / Orgánicos / Sistemas de Agua

The high pressure sapphire cell apparatus was constructed to visually determine the composition of multiphase systems without physical sampling. ...

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Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization

We demonstrate a method for high-throughput catalyst screening using a parallel pressure reactor starting from the initial synthesis of a nickel &#945;-diimine ethylene polymerization catalyst. Initial polymerizations with the catalyst lead to optimized reaction conditions, including catalyst concentration, ethylene pressure and reaction time. Using gas-uptake data for these reactions, a procedure to calculate the initial rate of propagation (kp) is presented. Using the optimized conditions, the ability of the nickel &#945;-diimine polymerization catalyst to undergo chain transfer with diethylzinc (ZnEt2) during ethylene polymerization was investigated. A procedure to assess the ability of the catalyst to undergo chain transfer (from molecular weight and 13C NMR data), calculate the degree of chain transfer, and calculate chain transfer rates (ke) is presented.

A protocol for the high-throughput analysis of polymerization catalyst, chain transfer polymerizations, polyethylene characterization, and reaction kinetic analysis is presented.

Las polimerizaciones de etileno utilizando reactores de presión paralelas y un análisis cinético de la cadena de transferencia de polimerización

We demonstrate a method for high-throughput catalyst screening using a parallel pressure reactor starting from the initial synthesis of a nickel ...

Preparation of Carbon Nanosheets at Room Temperature

Amphiphilic molecules equipped with a reactive, carbon-rich "oligoyne" segment consisting of conjugated carbon-carbon triple bonds self-assemble into defined aggregates in aqueous media and at the air-water interface. In the aggregated state, the oligoynes can then be carbonized under mild conditions while preserving the morphology and the embedded chemical functionalization. This novel approach provides direct access to functionalized carbon nanomaterials. In this article, we present a synthetic approach that allows us to prepare hexayne carboxylate amphiphiles as carbon-rich siblings of typical fatty acid esters through a series of repeated bromination and Negishi-type cross-coupling reactions. The obtained compounds are designed to self-assemble into monolayers at the air-water interface, and we show how this can be achieved in a Langmuir trough. Thus, compression of the molecules at the air-water interface triggers the film formation and leads to a densely packed layer of the molecules. The complete carbonization of the films at the air-water interface is then accomplished by cross-linking of the hexayne layer at room temperature, using UV irradiation as a mild external stimulus. The changes in the layer during this process can be monitored with the help of infrared reflection-absorption spectroscopy and Brewster angle microscopy. Moreover, a transfer of the carbonized films onto solid substrates by the Langmuir-Blodgett technique has enabled us to prove that they were carbon nanosheets with lateral dimensions on the order of centimeters.

We present the synthesis of an amphiphilic hexayne and its use in the preparation of carbon nanosheets at the air-water interface from a self-assembled monolayer of these reactive, carbon-rich molecular precursors.

Preparación de nanoláminas de carbono a temperatura ambiente

Amphiphilic molecules equipped with a reactive, carbon-rich "oligoyne" segment consisting of conjugated carbon-carbon triple bonds self-assemble into ...

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of trifluoromethoxylated aromatic compounds remains a formidable challenge in organic synthesis. Conventional approaches often suffer from poor substrate scope, or require use of highly toxic, difficult-to-handle, and/or thermally labile reagents. Herein, we report a user-friendly protocol for the synthesis of methyl 4-acetamido-3-(trifluoromethoxy)benzoate using 1-trifluoromethyl-1,2-benziodoxol-3(1H)-one (Togni reagent II). Treating methyl 4-(N-hydroxyacetamido)benzoate (1a) with Togni reagent II in the presence of a catalytic amount of cesium carbonate (Cs2CO3) in chloroform at RT afforded methyl 4-(N-(trifluoromethoxy)acetamido)benzoate (2a). This intermediate was then converted to the final product methyl 4-acetamido-3-(trifluoromethoxy)benzoate (3a) in nitromethane at 120 &#176;C. This procedure is general and can be applied to the synthesis of a broad spectrum of ortho-trifluoromethoxylated aniline derivatives, which could serve as useful synthetic building blocks for the discovery and development of new pharmaceuticals, agrochemicals, and functional materials.

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

An operationally simple procedure for the synthesis of ortho-trifluoromethoxylated aniline derivatives via a two-step sequence of O-trifluoromethylation of N-aryl-N-hydroxyacetamide followed by thermally induced intramolecular OCF3-migration is reported.

Protocolo para la Síntesis de<em&gt; Ortho</em&gt; derivados de anilina -trifluoromethoxylated

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of ...

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

We demonstrate that direct analysis in real time-high resolution mass spectrometry can be used to produce mass spectral profiles of botanical material, and that these chemical fingerprints can be used for plant species identification. The mass spectral data can be acquired rapidly and in a high throughput manner without the need for sample extraction, derivatization or pH adjustment steps. The use of this technique bypasses challenges presented by more conventional techniques including lengthy chromatography analysis times and resource intensive methods. The high throughput capabilities of the direct analysis in real time-high resolution mass spectrometry protocol, coupled with multivariate statistical analysis processing of the data, provide not only class characterization of plants, but also yield species and varietal information. Here, the technique is demonstrated with two psychoactive plant products, Mitragyna speciosa (Kratom) and Datura (Jimsonweed), which were subjected to direct analysis in real time-high resolution mass spectrometry followed by statistical analysis processing of the mass spectral data. The application of these tools in tandem enabled the plant materials to be rapidly identified at the level of variety and species.

A method for species identification of botanical material by direct analysis in real time-high resolution mass spectrometry and multivariate statistical analysis is presented.

Rápida de alto rendimiento Identificación de Especies de material botánico Uso del análisis directo en tiempo real de alta resolución Espectrometría de Masas

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

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.

Alta Presión cristal único Difracción en 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 ...

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.

Plasma de microondas sin equilibrio para una química eficiente a altas temperaturas

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

A Straightforward Method for Glucosinolate Extraction and Analysis with High-pressure Liquid Chromatography (HPLC)

Glucosinolates are a well-studied and highly diverse class of natural plant compounds. They play important roles in plant resistance, rapeseed oil quality, food flavoring, and human health. The biological activity of glucosinolates is released upon tissue damage, when they are mixed with the enzyme myrosinase. This results in the formation of pungent and toxic breakdown products, such as isothiocyanates and nitriles. Currently, more than 130 structurally different glucosinolates have been identified. The chemical structure of the glucosinolate is an important determinant of the product that is formed, which in turn determines its biological activity. The latter may range from detrimental (e.g., progoitrin) to beneficial (e.g., glucoraphanin). Each glucosinolate-containing plant species has its own specific glucosinolate profile. For this reason, it is important to correctly identify and reliably quantify the different glucosinolates present in brassicaceous leaf, seed, and root crops or, for ecological studies, in their wild relatives. Here, we present a well-validated, targeted, and robust method to analyze glucosinolate profiles in a wide range of plant species and plant organs. Intact glucosinolates are extracted from ground plant materials with a methanol-water mixture at high temperatures to disable myrosinase activity. Thereafter, the resulting extract is brought onto an ion-exchange column for purification. After sulfatase treatment, the desulfoglucosinolates are eluted with water and the eluate is freeze-dried. The residue is taken up in an exact volume of water, which is analyzed by high-pressure liquid chromatography (HPLC) with a photodiode array (PDA) or ultraviolet (UV) detector. Detection and quantification are achieved by conducting comparisons of the retention times and UV spectra of commercial reference standards. The concentrations are calculated based on a sinigrin reference curve and well-established response factors. The advantages and disadvantages of this straightforward method, when compared to faster and more technologically advanced methods, are discussed here.

A Straightforward Method for Glucosinolate Extraction and Analysis with High-pressure Liquid Chromatography HPLC

Here, we describe in great detail an established and robust protocol for the extraction of glucosinolates from ground plant materials. After an on-column sulfatase treatment of the extracts, the desulfoglucosinolates are eluted and analyzed by high-pressure liquid chromatography.

Un método sencillo para glucosinolatos Extracción y análisis de alta presión con cromatografía líquida (HPLC)

Glucosinolates are a well-studied and highly diverse class of natural plant compounds. They play important roles in plant resistance, rapeseed oil ...

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.

Un método conveniente para la extracción y análisis con cromatografía líquida de alta presión de los neurotransmisores catecolaminas y sus metabolitos

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

Experimental Methods for Efficient Solar Hydrogen Production in Microgravity Environment

Long-term space flights and cis-lunar research platforms require a sustainable and light life-support hardware which can be reliably employed outside the Earth's atmosphere. So-called 'solar fuel' devices, currently developed for terrestrial applications in the quest for realizing a sustainable energy economy on Earth, provide promising alternative systems to existing air-revitalization units employed on the International Space Station (ISS) through photoelectrochemical water-splitting and hydrogen production. One obstacle for water (photo-) electrolysis in reduced gravity environments is the absence of buoyancy and the consequential, hindered gas bubble release from the electrode surface. This causes the formation of gas bubble froth layers in proximity to the electrode surface, leading to an increase in ohmic resistance and cell-efficiency loss due to reduced mass transfer of substrates and products to and from the electrode. Recently, we have demonstrated efficient solar hydrogen production in microgravity environment, using an integrated semiconductor-electrocatalyst system with p-type indium phosphide as the light-absorber and a rhodium electrocatalyst. By nanostructuring the electrocatalyst using shadow nanosphere lithography and thereby creating catalytic 'hot spots' on the photoelectrode surface, we could overcome gas bubble coalescence and mass transfer limitations and demonstrated efficient hydrogen production at high current densities in reduced gravitation. Here, the experimental details are described for the preparations of these nanostructured devices and further on, the procedure for their testing in microgravity environment, realized at the Bremen Drop Tower during 9.3 s of free fall.

Efficient solar-hydrogen production has recently been realized on functionalized semiconductor-electrocatalyst systems in a photoelectrochemical half-cell in microgravity environment at the Bremen Drop Tower. Here, we report the experimental procedures for manufacturing the semiconductor-electrocatalyst device, details of the experimental set-up in the drop capsule and the experimental sequence during free fall.

Métodos experimentales para la producción eficiente de hidrógeno solar en el entorno de microgravedad

Long-term space flights and cis-lunar research platforms require a sustainable and light life-support hardware which can be reliably employed outside the ...