Financial support provided by National Science Foundation (CAREER award CHE-0847262. We thank Vapourtec Ltd and Enwave Optronics for equipment support, and Daniel Daleb of the University of Connecticut for his assistance in construction of the flow cell apparatus.

1. Encontre sinais adequados para monitoramento de reações <ol><li> Obter espectros Raman para todos os materiais de partida e do produto. </li><li> Overlay espectros e identificar uma banda intensa que é exclusivo para o produto. </li><li> Utilizar esta banda de Raman para monitorar o progresso da reacção. Uma banda em 1.608 cm-1 foi seleccionado neste caso. </li></ol> 2. Configure a célula de fluxo <ol><li> Obter uma célula de fluxo adequado. Aqui utilizar um com as seguintes dimensões: largura de 6,5 mm, altura de 20 mm, e um comprimento do percurso de 5 mm (Figura 2A). </li><li> Coloque a célula de fluxo de um recipiente que fornece um ambiente livre de luz ambiente. </li><li> Conectar tubagem para a entrada ea saída da célula de fluxo (neste caso, 1 mm ID tubagem PFA). </li></ol> 3. Interface do espectrômetro Raman com a célula de fluxo <ol><li> Obter um espectrómetro de Raman adequado com um conjunto óptico flexível que pode ser colocado em Cperder proximidade com a célula de fluxo. </li><li> Colocar o conjunto óptico através de uma abertura de tamanho adequado na caixa que contém o conjunto da célula de fluxo (Figura 2B). </li><li> Deslize o conjunto óptico até que toque a célula de fluxo e, em seguida, puxe-o de volta deixando uma lacuna de ~ 2 mm. </li><li> Encha com a célula de fluxo de 100% de acetona. </li><li> Ligue o espectrômetro Raman e adquirir espectros em modo contínuo-scan. </li><li> Concentre-se o laser movendo suavemente o tubo de luz uma fração de cada vez. Mantenha mover-se do tubo de luz até que o sinal é, na sua maior intensidade e os picos são nítidas e bem definidas. </li></ol><img alt="Figura 2" src="/files/ftp_upload/52393/52393fig2.jpg" /> Figura 2. (A) célula de fluxo e de interface (B) Raman utilizado. <a href="https://www.jove.com/files/ftp_upload/52393/52393fig2large.jpg" target="_blank">Por favor clique aqui para ver uma maior ve</a>rsion desta figura. 4. Prepare o Reagente e soluções solventes <ol><li> Adicionar salicilaldeído (6,106 g, 50 mmol, 1 equiv) e acetoacetato de etilo (6,507 g, 50 mmol, 1 equiv) para um balão volumétrico de 50 ml. </li><li> Adiciona-se acetato de etilo para um volume total de 50 ml e, em seguida, misturar completamente os conteúdos. </li><li> Transferir uma alíquota de 10 ml da solução de estoque a um frasco de vidro de 20 ml contendo uma barra de agitação magnética. Marque esse &quot;reagente&quot;. Vial </li><li> Em lugar de uma garrafa de 100 ml de 90 ml de acetato de etilo. Rotular esta garrafa &quot;solvente&quot;. Em lugar de uma garrafa de 100 ml de 90 ml de acetona. Rotular esta garrafa &quot;interceptar solvente&quot;. </li></ol> 5. Prepare o Aparelho Fluxo <ol><li> Assegure-se que a unidade de fluxo tem, pelo menos, duas bombas e classificá-los &quot;P1&quot; e &quot;P2&quot;. Identificar linhas de entrada de solventes e reagentes para cada bomba. Coloque as linhas de saída do &quot;Collect&quot; e linhas de &quot;resíduos&quot; em dois individual garrafas de 100 ml rotulado &quot;produto&quot; e &quot;resíduos&quot;, respectivamente. </li><li> Como um reactor, utilizar uma bobina de 10 ml de capacidade PFA susceptível de ser aquecida. </li><li> Ligar o tubo de saída P1 para a entrada do reactor de bobina PFA. </li><li> Instale um três portas éter-cetona de poliéter (PEEK) T-mixer após a bobina do reator. </li><li> Ligue o tubo de saída P2 para o tee-mixer, 180 ° do tubo de saída da bobina do reator. Conecte-se um pedaço de tubo para a terceira porta do Tee-mixer. Na outra extremidade deste tubo colocar um regulador de contra-pressão. </li><li> Conectar uma linha a partir da saída do regulador de contra-pressão para a entrada da célula de fluxo. Conecte uma linha a partir da saída da célula de fluxo para o &quot;/ recolha de resíduos&quot; switch. </li><li> Primeiro as linhas de solvente para ambos P1 e P2, bem como a linha de reagente para P1 com solvente. Mova a linha de reagente para P1 do frasco de solvente para o frasco de reagente. </li><li> Usando P1, passar acetato de etilo através do reactorbobina a 2 ml / min, até que ela está cheia. Passe acetona através de P2, com um caudal de 2 ml / min durante 2 min. </li><li> Ajustar as taxas de fluxo de solvente para ambos P1 e P2 para 1 ml / min. Ajuste o regulador de contra-pressão a uma pressão de 7 bar. Ajustar a temperatura da bobina do reactor até à temperatura desejada. </li><li> Verifique a equipamento é configurado como mostrado no esquema na Figura 3. </li><li> Uma vez que o sistema atinge a temperatura e pressão constante, verificar se há vazamentos e, em seguida, executar a reação. </li></ol><img alt="Figura 3" src="/files/ftp_upload/52393/52393fig3.jpg" /> Figura 3. Diagrama esquemático da configuração do equipamento utilizado para experiências de monitoramento de reação. <a href="https://www.jove.com/files/ftp_upload/52393/52393fig3large.jpg" target="_blank">Por favor clique aqui para ver uma versão maior desta figura.</a> 6. Monitorar o Reaction <ol><li> TakEA fundo de digitalização do / acetona sistema de solvente acetato de etilo, uma vez que passou através da célula de fluxo. Este será automaticamente subtraído de todas as verificações subseqüentes. </li><li> Configurar o espectrómetro de tomar varreduras de 15 segundos cada (neste caso, o espectrómetro de Raman foi definido como um tempo de integração 10 s, vagão = 3, e a média = 1). </li><li> Injectar piperidina (0,05 mL, 0,05 mmol, 0,1 equiv) de uma vez para dentro do frasco de vidro etiquetados &quot;reagente&quot;. </li><li> Depois de misturar muito bem, interruptor P1 de &quot;solvente&quot; para &quot;reagente&quot;. Defina o fluxo de saída para &quot;recolher&quot;. </li><li> Quando todo o material está completamente carregado, interruptor P1 do &quot;reagente&quot; de volta para &quot;solvente&quot;. Continue fluindo solvente através da bobina reactor durante mais 30 minutos. Uma vez transcorrido este tempo, desligar o aquecimento. </li><li> Por sua vez, bombas P1 e P2 desligado quando a temperatura da serpentina do reactor ter arrefecido até abaixo de 50 ° C. </li></ol> 7. Analisar os dados <ol&gt; <li> Exportar os dados do espectrômetro Raman para uma planilha e enredo Raman intensidade em 1.608 centímetros -1 vs. Tempo. </li><li> Para otimizar as condições, realizar a reacção através de um número de caudais e temperaturas do reactor de forma iterativa. </li><li> Gráficos sobrepostos de Raman intensidade em 1608 centímetros -1 vs. Tempo. Nota: Raman Superior intensidade correlaciona-se com uma conversão mais elevada do produto. </li></ol> 8. Execute o Reaction Usando condições otimizadas <ol><li> Tendo rastreadas várias condições (taxas de fluxo variando / temperaturas do reator), executar a reação utilizando as condições otimizadas para proporcionar o maior conversão do produto. </li></ol> 9. Isolar o produto <ol><li> Tome o conteúdo do frasco do produto e despeje-o em um copo contendo 100 ml de gelo e 20 ml de HCl 2 M. </li><li> Lavar o balão de produto com uma quantidade mínima de acetato de etilo (2 ml) e transferir para a proveta. </li><li> Mexa a mistura geladaaté que todo o gelo é completamente derretido. </li><li> Configurar um sistema de filtração com um funil de Hirsch, frasco lateral-braço, colar de borracha e um pedaço de tubo de vácuo de borracha. </li><li> Filtra-se o precipitado resultante sob vácuo, lavar com éter dietílico frio (10 ml) e permitir que ele para secar sob uma lâmpada de calor (2-3 h) ou O seco / N sob vácuo. </li><li> Confirmam a identidade do produto por 1H ressonância magnética (RMN) nuclear usando CDCI3 como solvente. Para um espectrómetro de RMN de 500 MHz, os dados de 1 H RMN de 3-acetylcoumarin é como se segue: δ = 2,73 (s, 3 H) 7,31 - 7,40 (m, 2 H) 7,65 (ddd, J = 7,53, 4,37, 2,60 Hz , 2 H) 8,51 (s, 1H) ppm, 13 de dados C RMN: δ = 30,84 (CH3) 117.00 (CH), 118,56 (C), 124,86 (CH), 125,27 (CH), 130,51 (CH), 134,68 (C) 147,74 (CH) 155,64 (C), 159,52 (C), 195,77 (C) ppm. </li></ol>

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The authors have nothing to disclose.

A facilidade com que o espectrómetro de Raman pode ser interligado com a unidade de fluxo faz com que esta técnica valiosa para a monitorização em linha de reacção. Um certo número de variáveis ​​de reacção pode ser sondado de modo expedito, permitindo que o utilizador chegar a condições de reacção optimizadas rápido do que quando utilizando métodos off-line. A aplicação das técnicas aqui descritas, permite também a monitorização da formação de produtos secundários, assumindo uma banda aprop...

Ao usar o processamento de fluxo contínuo, os químicos estão descobrindo que eles podem realizar uma série de reações químicas de forma segura, eficaz e com facilidade 1,2. Como resultado, química equipamento fluxo está se tornando uma ferramenta integral para a execução de reações tanto em ambientes industriais, bem como laboratórios de pesquisa em instituições acadêmicas. Uma ampla variedade de transformações de química de síntese foram efectuadas em reactores de fluxo de 3,4. Em casos seleccionados, as reacções que não funcionam em modo descontínuo têm sido mostrados para prosseguir suavemente sob condições de fluxo contínuo 5. Para tanto optimização da reacção e o controlo de qualidade, monitorização da incorporação de reacção em conformidade com o processamento de fluxo oferece vantagens significativas. Monitoramento em linha fornece uma análise contínua com resposta em tempo real às condições reais de amostra. Isto é mais rápido e, em alguns casos, mais fiável do que as técnicas comparáveis ​​off-line. Um número de técnicas de análise em linha foram interface com fbaixos reatores 7. Exemplos incluem 8,9 infravermelho, ultravioleta-visível 10,11, 12,13 RMN, espectroscopia de Raman, 14,15, 16,17 e espectrometria de massa. Nosso grupo de pesquisa tem interagido um espectrômetro Raman com uma unidade de microondas científica 18. Usando isso, uma série de reações foram monitoradas, tanto qualitativa e quantitativa 20 19 ponto de vista. Com base neste sucesso, temos interface recentemente o nosso espectrômetro Raman com uma de nossas unidades de fluxo contínuo e empregou-o para o monitoramento de uma série de transformações orgânicas chave relevantes para a medicinalmente reacção in-line. 21 Em cada caso, foi possível monitorar o reacções e também num exemplo, por meio de uma curva de calibração, que pode determinar a conversão do produto a partir dos dados de espectroscopia Raman. Na Aqui nós descrevemos como configurar o aparelho e usá-lo para monitorar reações. Usamos a síntese catalisada por piperidina de 3-acetylcoumarin (1) a partir de salicilaldeído com acetoacetato de etilo (Figura 1) como o modelo de reacção aqui. <img alt="figura 1" src="/files/ftp_upload/52393/52393fig1.jpg" /> Figura 1. Base de reação catalisada condensação entre salicilaldeï¿½o e acetoacetato de etilo para produzir 3-acetylcoumarin (1). <a href="https://www.jove.com/files/ftp_upload/52393/52393fig1large.jpg" target="_blank">Por favor clique aqui para ver uma versão maior desta figura.</a>

<table border="0">
	<tbody>
		<tr>
			<td>Salicylaldehyde</td>
			<td>Sigma-Aldrich</td>
			<td>S356</td>
			<td>Reagent Grade, 98%</td>
		</tr>
		<tr>
			<td>Ethyl acetoacetate</td>
			<td>Acros Organics</td>
			<td>117970010</td>
			<td>99%</td>
		</tr>
		<tr>
			<td>Piperidine</td>
			<td>Sigma-Aldrich</td>
			<td>104094</td>
			<td>Reagent Plus, 99%</td>
		</tr>
		<tr>
			<td>Hydrochloric acid</td>
			<td>Sigma-Aldrich</td>
			<td>320331</td>
			<td>ACS Reagent, 37%</td>
		</tr>
		<tr>
			<td>Ethyl acetate</td>
			<td>Sigma-Aldrich</td>
			<td>34858</td>
			<td>CHROMASOLV, for HPLC, &#62;99.7%</td>
		</tr>
		<tr>
			<td>Acetone</td>
			<td>Sigma-Aldrich</td>
			<td>650501</td>
			<td>CHROMASOLV, for HPLC, &#62;99.9%</td>
		</tr>
		<tr>
			<td>Flow cell</td>
			<td>Starna Cells</td>
			<td></td>
			<td>583.65.65-Q-5/Z20</td>
		</tr>
		<tr>
			<td>Flow unit</td>
			<td>Vapourtec</td>
			<td></td>
			<td>E-series system</td>
		</tr>
		<tr>
			<td>Raman spectrometer</td>
			<td>Enwave Optronics Inc</td>
			<td></td>
			<td>Model EZRaman-L</td>
		</tr>
	</tbody>
</table>

real-time monitoring of reactions performed using continuous-flow processing: the preparation of 3-acetylcoumarin as an example

Ao utilizar a monitorização em linha, é possível optimizar as reacções realizadas utilizando o processamento contínuo de fluxo de uma maneira simples e rápida. Também é possível assegurar uma qualidade de produto consistente ao longo do tempo utilizando esta técnica. Nós aqui mostrar como a interface de uma unidade de fluxo disponível comercialmente com um espectrômetro Raman. A célula de fluxo de Raman é colocado após o regulador de contra-pressão, o que significa que ele pode ser operado à pressão atmosférica. Além disso, o facto de a corrente de produto passa através de um comprimento de tubagem antes de entrar na célula de fluxo significa que o material é, à TA. É importante que os espectros são adquiridas sob condições isotérmicas uma vez que a intensidade do sinal de Raman é dependente da temperatura. Tendo reunido o aparelho, que em seguida mostram como monitorar uma reacção química, a síntese catalisada por piperidina de 3-acetylcoumarin de salicilaldeído e acetoacetato de etilo a ser utilizado como um exemplo. A reacção pode ser realizada sobre uma gama de caudais umatemperaturas D, a ferramenta de monitoramento in-situ sendo usado para otimizar as condições de forma simples e fácil.

A preparação contínua de fluxo de 3-acetylcoumarin foi escolhido como representativo de uma reacção para a monitorização em linha. No lote, a reacção processa-se bem quando se utiliza acetato de etilo como o solvente. No entanto, o produto (1) não é completamente solúvel à temperatura ambiente. Para evitar potencial entupimento do regulador de contra-pressão, bem como minimizar o risco de ter partículas sólidas na célula de fluxo que iria perturbar a aquisição de sinal, utilizou-se um...

Watch this Scientific Journal Video about Real-time Monitoring of Reactions Performed Using Continuous-flow Processing: The Preparation of 3-Acetylcoumarin as an Example at JoVE.com

Real-time Monitoring of Reactions Performed Using Continuous-flow Processing: The Preparation of 3-Acetylcoumarin as an Example

Monitoramento em tempo real permite a otimização rápida de reações realizadas utilizando o processamento de fluxo contínuo. Aqui, a preparação de 3-acetylcoumarin é utilizado como um exemplo. O aparelho para a realização in situ de monitorização de Raman está descrito, assim como os passos necessários para a optimização da reacção.

Monitoramento em tempo real de Reações realizada utilizando processamento de fluxo contínuo: A Preparação de 3-Acetylcoumarin como Exemplo

By using inline monitoring, it is possible to optimize reactions performed using continuous-flow processing in a simple and rapid way. It is also possible ...

real-time-monitoring-reactions-performed-using-continuous-flow

Research

JoVE Journal

Chemistry

9.6K visualizações.  University of Connecticut.  Monitoramento em tempo real permite a otimização rápida de reações realizadas utilizando o processamento de fluxo contínuo. Aqui, a preparação de 3-acetylcoumarin é utilizado como um exemplo. O aparelho para a realização in situ de monitorização de Raman está descrito, assim como os passos necessários para a optimização da reacção. 

Vídeo: Real-time Monitoring of Reactions Performed Using Continuous-flow Processing: The Preparation of 3-Acetylcoumarin as an Example

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 alta capacidade: Identificação de Espécies de material botânico Usando Direct Análise em Tempo Real alta resolução Espectrometria de Massa

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

Química

Capillary Electrophoresis to Monitor Peptide Grafting onto Chitosan Films in Real Time

Free-solution capillary electrophoresis (CE) separates analytes, generally charged compounds in solution through the application of an electric field. Compared to other analytical separation techniques, such as chromatography, CE is cheap, robust and effectively requires no sample preparation (for a number of complex natural matrices or polymeric samples). CE is fast and can be used to follow the evolution of mixtures in real time (e.g., chemical reaction kinetics), as the signals observed for the separated compounds are directly proportional to their quantity in solution.
Here, the efficiency of CE is demonstrated for monitoring the covalent grafting of peptides onto chitosan films for subsequent biomedical applications. Chitosan&#39;s antimicrobial and biocompatible properties make it an attractive material for biomedical applications such as cell growth substrates. Covalently grafting the peptide RGDS (arginine - glycine - aspartic acid - serine) onto the surface of chitosan films aims at improving cell attachment. Historically, chromatography and amino acid analysis have been used to provide a direct measurement of the amount of grafted peptide. However, the fast separation and absence of sample preparation provided by CE enables equally accurate yet real-time monitoring of the peptide grafting process. CE is able to separate and quantify the different components of the reaction mixture: the (non-grafted) peptide and the chemical coupling agents. In this way the use of CE results in improved films for downstream applications.
The chitosan films were characterized through solid-state NMR (nuclear magnetic resonance) spectroscopy. This technique is more time-consuming and cannot be applied in real time, but yields a direct measurement of the peptide and thus validates the CE technique.

Free solution capillary electrophoresis is a fast, cheap and robust analytical method that enables the quantitative monitoring of chemical reactions in real time. Its utility for rapid, convenient and precise analysis is demonstrated here through analysis of covalent peptide grafting onto chitosan films for improved cell adhesion.

Eletroforese Capilar para monitorar Peptide Enxertia em quitosana Films em Tempo real

Free-solution capillary electrophoresis (CE) separates analytes, generally charged compounds in solution through the application of an electric field. ...

A Protocol for Safe Lithiation Reactions Using Organolithium Reagents

Organolithium reagents are powerful tools in the synthetic chemist&#39;s toolbox. However, the extreme pyrophoric nature of the most reactive reagents warrants proper technique, thorough training, and proper personal protective equipment. To aid in the training of researchers using organolithium reagents, a thorough, step-by-step protocol for the safe and effective use of tert-butyllithium on an inert gas line or within a glovebox is described. As a model reaction, preparation of lithium tert-butyl amide by the reaction of tert-butyl amine with one equivalent of tert-butyl lithium is presented.

The safe and proper use of organolithium reagents is described.

Um protocolo para reações seguras litiação Usando organolï¿½io Reagentes

Organolithium reagents are powerful tools in the synthetic chemist&#39;s toolbox. However, the extreme pyrophoric nature of the most reactive reagents ...

Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering

We demonstrate a protocol to effectively monitor the gelation process of a high concentration solution of conjugated polymer both in the presence and absence of white light exposure. By instituting a controlled temperature ramp, the gelation of these materials can be precisely monitored as they proceed through this structural evolution, which effectively mirrors the conditions experienced during the solution deposition phase of organic electronic device fabrication. Using small angle neutron scattering (SANS) and ultra-small angle neutron scattering (USANS) along with appropriate fitting protocols we quantify the evolution of select structural parameters throughout this process. Thorough analysis indicates that continued light exposure throughout the gelation process significantly alters the structure of the ultimately formed gel. Specifically, the aggregation process of poly(3-hexylthiophene-2,5-diyl) (P3HT) nano-scale aggregates is negatively affected by the presence of illumination, ultimately resulting in the retardation of growth in conjugated polymer microstructures and the formation of smaller scale macro-aggregate clusters.

A protocol for the analysis of gels formed from the optoelectronic conjugated polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) using small and ultra-small angle neutron scattering in both the presence and absence of illumination is presented.

Monitorização dos efeitos de iluminação sobre a estrutura do polímero conjugado géis usando Neutron Scattering

We demonstrate a protocol to effectively monitor the gelation process of a high concentration solution of conjugated polymer both in the presence and ...

Measurements of Long-range Electronic Correlations During Femtosecond Diffraction Experiments Performed on Nanocrystals of Buckminsterfullerene

The precise details of the interaction of intense X-ray pulses with matter are a topic of intense interest to researchers attempting to interpret the results of femtosecond X-ray free electron laser (XFEL) experiments. An increasing number of experimental observations have shown that although nuclear motion can be negligible, given a short enough incident pulse duration, electronic motion cannot be ignored. The current and widely accepted models assume that although electrons undergo dynamics driven by interaction with the pulse, their motion could largely be considered &#39;random&#39;. This would then allow the supposedly incoherent contribution from the electronic motion to be treated as a continuous background signal and thus ignored. The original aim of our experiment was to precisely measure the change in intensity of individual Bragg peaks, due to X-ray induced electronic damage in a model system, crystalline C60. Contrary to this expectation, we observed that at the highest X-ray intensities, the electron dynamics in C60 were in fact highly correlated, and over sufficiently long distances that the positions of the Bragg reflections are significantly altered. This paper describes in detail the methods and protocols used for these experiments, which were conducted both at the Linac Coherent Light Source (LCLS) and the Australian Synchrotron (AS) as well as the crystallographic approaches used to analyse the data.

We describe an experiment designed to probe the electronic damage induced in nanocrystals of Buckminsterfullerene (C60) by intense, femtosecond pulses of X-rays. The experiment found that, surprisingly, rather than being stochastic, the X-ray induced electron dynamics in C60 are highly correlated, extending over hundreds of unit cells within the crystals1.

Medições de correlações eletrônicas de longo alcance durante experimentos de difração de femtossegundo realizados em nanocristais de Buckminsterfulereno

The precise details of the interaction of intense X-ray pulses with matter are a topic of intense interest to researchers attempting to interpret the ...

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.

Análise de respiração em tempo real usando o Nanoelectrospray secundário ionização acoplada a espectrometria de massa de alta resolução

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

Continuous Flow Chemistry: Reaction of Diphenyldiazomethane with p-Nitrobenzoic Acid

Continuous flow technology has been identified as instrumental for its environmental and economic advantages leveraging superior mixing, heat transfer and cost savings through the &#34;scaling out&#34; strategy as opposed to the traditional &#34;scaling up&#34;. Herein, we report the reaction of diphenyldiazomethane with p-nitrobenzoic acid in both batch and flow modes. To effectively transfer the reaction from batch to flow mode, it is essential to first conduct the reaction in batch. As a consequence, the reaction of diphenyldiazomethane was first studied in batch as a function of temperature, reaction time, and concentration to obtain kinetic information and process parameters. The glass flow reactor set-up is described and combines two types of reaction modules with &#34;mixing&#34; and &#34;linear&#34; microstructures. Finally, the reaction of diphenyldiazomethane with p-nitrobenzoic acid was successfully conducted in the flow reactor, with up to 95% conversion of the diphenyldiazomethane in 11 min. This proof of concept reaction aims to provide insight for scientists to consider flow technology&#39;s competitiveness, sustainability, and versatility in their research.

Continuous Flow Chemistry: Reaction of Diphenyldiazomethane with p-Nitrobenzoic Acid

Flow chemistry carries environmental and economic advantages by leveraging superior mixing, heat transfer and cost benefits. Herein, we provide a blueprint to transfer chemical processes from batch to flow mode. The reaction of diphenyldiazomethane (DDM) with p-nitrobenzoic acid, conducted in batch and flow, was chosen for proof of concept.

Química de Fluxo Contínuo: Reação de Difenildiazometano com Ácido p-Nitrobenzoico

Continuous flow technology has been identified as instrumental for its environmental and economic advantages leveraging superior mixing, heat transfer and ...

A Continuous-flow Photocatalytic Reactor for the Precisely Controlled Deposition of Metallic Nanoparticles

In this work, a novel photocatalytic reactor for the pulsed and controlled excitation of the photocatalyst and the precise deposition of metallic nanoparticles is developed. Guidelines for the replication of the reactor and its operation are provided in detail. Three different composite systems (Pt/graphene, Pt/TiO2, and Au/TiO2) with monodisperse and uniformly distributed particles are produced by this reactor, and the photodeposition mechanism, as well as the synthesis optimization strategy, are discussed. The synthesis methods and their technical aspects are described comprehensively. The role of the ultraviolet (UV) dose (in each excitation pulse) on the photodeposition process is investigated and the optimum values for each composite system are provided.

For a continuous and scalable synthesis of noble-metal-based nanocomposites, a novel photocatalytic reactor is developed and its structure, operation principles, and product quality optimization strategies are described.

Um reator de fluxo contínuo fotocatalítico para a deposição controlada precisamente de nanopartículas metálicas

In this work, a novel photocatalytic reactor for the pulsed and controlled excitation of the photocatalyst and the precise deposition of metallic ...

Technical Aspect of the Automated Synthesis and Real-Time Kinetic Evaluation of [11C]SNAP-7941

Positron emission tomography (PET) is an essential molecular imaging technique providing insights into pathways and using specific targeted radioligands for in vivo investigations. Within this protocol, a robust and reliable remote-controlled radiosynthesis of [11C]SNAP-7941, an antagonist to the melanin-concentrating hormone receptor 1, is described. The radiosynthesis starts with cyclotron produced [11C]CO2 that is subsequently further reacted via a gas-phase transition to [11C]CH3OTf. Then, this reactive intermediate is introduced to the precursor solution and forms the respective radiotracer. Chemical as well as the radiochemical purity are determined by means of RP-HPLC, routinely implemented in the radiopharmaceutical quality control process. Additionally, the molar activity is calculated as it is a necessity for the following real-time kinetic investigations. Furthermore, [11C]SNAP-7941 is applied to MDCKII-WT and MDCKII-hMDR1 cells for evaluating the impact of P-glycoprotein (P-gp) expression on cell accumulation. For this reason, the P-gp expressing cell line (MDCKII-hMDR1) is either used without or with blocking prior to experiments by means of the P-gp substrate (&#177;)-verapamil and the results are compared to the ones observed for the wildtype cells. The overall experimental approach demonstrates the importance of a precise time-management that is essential for every preclinical and clinical study using PET tracers radiolabelled with short-lived nuclides, such as carbon-11 (half-life: 20 min).

Technical Aspect of the Automated Synthesis and Real-Time Kinetic Evaluation of [11C]SNAP-7941

Here, we represent a protocol for the fully automated radiolabelling of [11C]SNAP-7941 and the analysis of the real-time kinetics of this PET-tracer on P-gp expressing and non-expressing cells.

Aspecto técnico da síntese automatizada e avaliação cinética em tempo real de [11C] SNAP-7941

Positron emission tomography (PET) is an essential molecular imaging technique providing insights into pathways and using specific targeted radioligands ...

Optimization of Radiochemical Reactions using Droplet Arrays

Current automated radiosynthesizers are designed to produce large clinical batches of radiopharmaceuticals. They are not well suited for reaction optimization or novel radiopharmaceutical development since each data point involves significant reagent consumption, and contamination of the apparatus requires time for radioactive decay before the next use. To address these limitations, a platform for performing arrays of miniature droplet-based reactions in parallel, each confined within a surface-tension trap on a patterned polytetrafluoroethylene-coated silicon "chip", was developed. These chips enable rapid and convenient studies of reaction parameters including reagent concentrations, reaction solvent, reaction temperature and time. This platform permits the completion of hundreds of reactions in a few days with minimal reagent consumption, instead of taking months using a conventional radiosynthesizer.

This method describes the use of a novel high-throughput methodology, based on droplet chemical reactions, for the rapid and economical optimization of radiopharmaceuticals using nanomole amounts of reagents.