T_1ρ is an NMR relaxation mode which is sensitive to low frequency molecular motions, making it a... more T_1ρ is an NMR relaxation mode which is sensitive to low frequency molecular motions, making it an especially valuable tool in biomolecular research. Here, we introduce a new method, SPICY,...
Microreactors attract a significant interest for chemical synthesis due to benefits of small scal... more Microreactors attract a significant interest for chemical synthesis due to benefits of small scales such as high surface to volume ratio, rapid thermal ramping and well-understood laminar flows. The suitability of atomic layer deposition for applying of both the catalyst nanoparticles and the support material on the surfaces of channels of microfabricated silicon microreactors is demonstrated in this research. Continuous flow hydrogenation of propene into propane at low temperatures with TiO 2 supported catalytic Pt nanoparticles was used as a model reaction. Reaction yield and mass transport were monitored by high sensitivity microcoil Nuclear Magnetic Resonance (NMR) spectroscopy as well as time-of-flight remote detection NMR imaging. The microreactors were shown to be very efficient in propene conversion into propane. The yield of 100 % was achieved at 50 °C with a reactor decorated with Pt nanoparticles of average size of ca. 1 nm and surface coverage of 3.2 % in 20 mm long reaction channels with the residence time of 1100 ms. The activity of the Pt catalyst surfaces was on the order of few to tens of mmol s-1 m-2 .
The development of microfluidic processes requires information-rich detection methods. Here we in... more The development of microfluidic processes requires information-rich detection methods. Here we introduce the concept of remote detection exchange NMR spectroscopy (RD-EXSY), and show that, along with indirect spatial information extracted from time-of-flight data, it provides unique information about the active regions, reaction pathways, and intermediate products in a lab-on-a-chip reactor. Furthermore, we demonstrate that direct spatial resolution can be added to RD-EXSY efficiently by applying the principles of Hadamard spectroscopy. Microfluidics exhibit revolutionary new technological capabilities due to the precise and flexible channel design, efficient heat exchange, high mechanical stability, and economical use of reactants. [1] Microfluidic processes, such as chemical reactions, protein crystallization, cell growth, drug discovery, and health diagnostics, [2] are traditionally monitored by optical, electrochemical, and mass spectrometry methods. [3] Nuclear magnetic resonance (NMR) spectroscopy [4] is one of the most powerful analytical techniques, because it provides versatile spectroscopic, spatial, and dynamic information, and, contrary to optical methods, it allows the noninvasive, tracer-less analysis of opaque materials. The versatile analytical toolbox of NMR spectroscopy can also be exploited in microfluidic applications, if the sensitivity is boosted by using ultrasensitive miniaturized coil designs,
The subject of this thesis is the characterization of chemical reactions and adsorption by means ... more The subject of this thesis is the characterization of chemical reactions and adsorption by means of remote detection (RD) method of nuclear magnetic resonance (NMR). The thesis consists of three related topics: In the first one, novel RD NMR based methods for characterizing chemical reactions were presented. In the second topic RD NMR methods were used to study the performance of new kind of microfluidic reactors. The third project concentrated on the development of a novel way to quantify the adsorption of flowing gas mixtures in porous materials. Even though all the topics cover quite different areas of research, they have few common nominators: remote detection NMR, microfluidics and method development. Microfluidic devices are of interest for many areas of science (such as molecular biology, disease diagnosis, chemistry) as they offer great promises for future technologies. Small dimensions enable, among many other things, the benefits of small sample volumes, large surface to v...
The exchange of molecules between different physical or chemical environments due to diffusion or... more The exchange of molecules between different physical or chemical environments due to diffusion or chemical transformations has a crucial role in a plethora of fundamental processes such as breathing, protein folding, chemical reactions and catalysis. Here, we introduce a method for a single-scan, ultrafast NMR analysis of molecular exchange based on the diffusion coefficient contrast. The method shortens the experiment time by one to four orders of magnitude. Consequently, it opens the way for high sensitivity quantification of important transient physical and chemical exchange processes such as in cellular metabolism. As a proof of principle, we demonstrate that the method reveals the structure of aggregates formed by surfactants relevant to aerosol research.
The exchange of molecules between different physical or chemical environments due to diffusion or... more The exchange of molecules between different physical or chemical environments due to diffusion or chemical transformations has a crucial role in a plethora of fundamental processes such as breathing, protein folding, chemical reactions and catalysis. Here, we introduce a method for a single-scan, ultrafast NMR analysis of molecular exchange based on the diffusion coefficient contrast. The method shortens the experiment time by one to four orders of magnitude. Consequently, it opens the way for high sensitivity quantification of important transient physical and chemical exchange processes such as in cellular metabolism. As a proof of principle, we demonstrate that the method reveals the structure of aggregates formed by surfactants relevant to aerosol research.
The development of microfluidic processes requires information-rich detection methods. Here we in... more The development of microfluidic processes requires information-rich detection methods. Here we introduce the concept of remote detection exchange NMR spectroscopy (RD-EXSY), and show that, along with indirect spatial information extracted from time-of-flight data, it provides unique information about the active regions, reaction pathways, and intermediate products in a lab-on-a-chip reactor. Furthermore, we demonstrate that direct spatial resolution can be added to RD-EXSY efficiently by applying the principles of Hadamard spectroscopy.
T_1ρ is an NMR relaxation mode which is sensitive to low frequency molecular motions, making it a... more T_1ρ is an NMR relaxation mode which is sensitive to low frequency molecular motions, making it an especially valuable tool in biomolecular research. Here, we introduce a new method, SPICY,...
Microreactors attract a significant interest for chemical synthesis due to benefits of small scal... more Microreactors attract a significant interest for chemical synthesis due to benefits of small scales such as high surface to volume ratio, rapid thermal ramping and well-understood laminar flows. The suitability of atomic layer deposition for applying of both the catalyst nanoparticles and the support material on the surfaces of channels of microfabricated silicon microreactors is demonstrated in this research. Continuous flow hydrogenation of propene into propane at low temperatures with TiO 2 supported catalytic Pt nanoparticles was used as a model reaction. Reaction yield and mass transport were monitored by high sensitivity microcoil Nuclear Magnetic Resonance (NMR) spectroscopy as well as time-of-flight remote detection NMR imaging. The microreactors were shown to be very efficient in propene conversion into propane. The yield of 100 % was achieved at 50 °C with a reactor decorated with Pt nanoparticles of average size of ca. 1 nm and surface coverage of 3.2 % in 20 mm long reaction channels with the residence time of 1100 ms. The activity of the Pt catalyst surfaces was on the order of few to tens of mmol s-1 m-2 .
The development of microfluidic processes requires information-rich detection methods. Here we in... more The development of microfluidic processes requires information-rich detection methods. Here we introduce the concept of remote detection exchange NMR spectroscopy (RD-EXSY), and show that, along with indirect spatial information extracted from time-of-flight data, it provides unique information about the active regions, reaction pathways, and intermediate products in a lab-on-a-chip reactor. Furthermore, we demonstrate that direct spatial resolution can be added to RD-EXSY efficiently by applying the principles of Hadamard spectroscopy. Microfluidics exhibit revolutionary new technological capabilities due to the precise and flexible channel design, efficient heat exchange, high mechanical stability, and economical use of reactants. [1] Microfluidic processes, such as chemical reactions, protein crystallization, cell growth, drug discovery, and health diagnostics, [2] are traditionally monitored by optical, electrochemical, and mass spectrometry methods. [3] Nuclear magnetic resonance (NMR) spectroscopy [4] is one of the most powerful analytical techniques, because it provides versatile spectroscopic, spatial, and dynamic information, and, contrary to optical methods, it allows the noninvasive, tracer-less analysis of opaque materials. The versatile analytical toolbox of NMR spectroscopy can also be exploited in microfluidic applications, if the sensitivity is boosted by using ultrasensitive miniaturized coil designs,
The subject of this thesis is the characterization of chemical reactions and adsorption by means ... more The subject of this thesis is the characterization of chemical reactions and adsorption by means of remote detection (RD) method of nuclear magnetic resonance (NMR). The thesis consists of three related topics: In the first one, novel RD NMR based methods for characterizing chemical reactions were presented. In the second topic RD NMR methods were used to study the performance of new kind of microfluidic reactors. The third project concentrated on the development of a novel way to quantify the adsorption of flowing gas mixtures in porous materials. Even though all the topics cover quite different areas of research, they have few common nominators: remote detection NMR, microfluidics and method development. Microfluidic devices are of interest for many areas of science (such as molecular biology, disease diagnosis, chemistry) as they offer great promises for future technologies. Small dimensions enable, among many other things, the benefits of small sample volumes, large surface to v...
The exchange of molecules between different physical or chemical environments due to diffusion or... more The exchange of molecules between different physical or chemical environments due to diffusion or chemical transformations has a crucial role in a plethora of fundamental processes such as breathing, protein folding, chemical reactions and catalysis. Here, we introduce a method for a single-scan, ultrafast NMR analysis of molecular exchange based on the diffusion coefficient contrast. The method shortens the experiment time by one to four orders of magnitude. Consequently, it opens the way for high sensitivity quantification of important transient physical and chemical exchange processes such as in cellular metabolism. As a proof of principle, we demonstrate that the method reveals the structure of aggregates formed by surfactants relevant to aerosol research.
The exchange of molecules between different physical or chemical environments due to diffusion or... more The exchange of molecules between different physical or chemical environments due to diffusion or chemical transformations has a crucial role in a plethora of fundamental processes such as breathing, protein folding, chemical reactions and catalysis. Here, we introduce a method for a single-scan, ultrafast NMR analysis of molecular exchange based on the diffusion coefficient contrast. The method shortens the experiment time by one to four orders of magnitude. Consequently, it opens the way for high sensitivity quantification of important transient physical and chemical exchange processes such as in cellular metabolism. As a proof of principle, we demonstrate that the method reveals the structure of aggregates formed by surfactants relevant to aerosol research.
The development of microfluidic processes requires information-rich detection methods. Here we in... more The development of microfluidic processes requires information-rich detection methods. Here we introduce the concept of remote detection exchange NMR spectroscopy (RD-EXSY), and show that, along with indirect spatial information extracted from time-of-flight data, it provides unique information about the active regions, reaction pathways, and intermediate products in a lab-on-a-chip reactor. Furthermore, we demonstrate that direct spatial resolution can be added to RD-EXSY efficiently by applying the principles of Hadamard spectroscopy.
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Papers by Anne Selent