The establishment of an efficient reaction mixture represents a crucial part of capillary electrophoresis based on-line enzymatic assays. For ketamine N-demethylation to norketamine mediated by the cytochrome P450 3A4 enzyme, mixing of enzyme and reactants in the incubation buffer at physiological pH was studied by computer simulation. A dynamic electrophoretic simulator that encompasses Taylor-Aris diffusivity which accounts for dispersion due to the parabolic flow profile associated with pressure driven flow was utilized. The simulator in the diffusion mode was used to predict transverse diffusional reactant mixing occurring during hydrodynamic plug injection of configurations featuring four and seven plugs. The same simulator in the electrophoretic mode was applied to study electrophoretic reactant mixing caused by voltage application in absence of buffer flow. Resulting conclusions were experimentally verified with enantioselective analysis of norketamine in a background electrolyte at low pH. Furthermore, simulations visualize buffer changes that occur upon power application between incubation buffer and background electrolyte and have an influence on the reaction mixture.
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http://dx.doi.org/10.1016/j.chroma.2016.10.002 | DOI Listing |
Anal Chem
January 2025
Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.
This study describes a microfluidic thread-based analytical device (μTAD) capable of in situ mass spectrometric analysis for continuous flow reaction monitoring. Organic reaction screening is foundational to drug discovery. Microfluidic devices are of special interest here because they provide continuous reaction monitoring with advantages such as the use of smaller reagent volumes and short analysis times.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
School of Mechanical and Electrical Engineering, Guangdong University of Science and Technology, Dongguan 523083, China.
Tunnel oxide passivating contact cells have become the mainstream form of high-performance photovoltaic cells; however, the key factor restricting the further improvement of tunnel oxide passivating contact cell performance lies in the deposition process technology of high-quality polysilicon films. The experimental optimization cost for the deposition of large-sized polysilicon films in low-pressure chemical vapor deposition reactors is enormous when conducted in the temperature range of 800-950 K; hence, the necessity to develop effective computer simulation models becomes urgent. In recent years, our research group has conducted two-dimensional simulation research on large-sized, low-pressure chemical vapor deposition.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Faculty of Computer Science, Dresden University of Technology, Dresden, Germany.
We show that the resolution-dependent loss of bimolecular reactions in spatiotemporal Reaction-Diffusion Master Equations (RDMEs) is in agreement with the mean-field Collins-Kimball (C-K) theory of diffusion-limited reaction kinetics. The RDME is a spatial generalization of the chemical master equation, which enables studying stochastic reaction dynamics in spatially heterogeneous systems. It uses a regular Cartesian grid to partition space into locally well-mixed reaction compartments and treats diffusion as a jump reaction between neighboring grid cells.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States.
Electrochemical activation of dinitrogen (N) is notoriously challenging, typically yielding very low ammonia (NH) production rates. In this study, we present a continuous flow plasma-electrochemical reactor system for the direct conversion of nitrogen from air into ammonia. In our system, nitrogen molecules are first converted into a mixture of NO species in the plasma reactor, which are then fed into an electrochemical reactor.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Department of Earth and Environmental Sciences, College of Science and Engineering, University of Minnesota, Minneapolis, MN 55455.
Solute transport and biogeochemical reactions in porous and fractured media flows are controlled by mixing, as are subsurface engineering operations such as contaminant remediation, geothermal energy production, and carbon sequestration. Porous media flows are generally regarded as slow, so the effects of fluid inertia on mixing and reaction are typically ignored. Here, we demonstrate through microfluidic experiments and numerical simulations of mixing-induced reaction that inertial recirculating flows readily emerge in laminar porous media flows and dramatically alter mixing and reaction dynamics.
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