Traveling wave ion mobility mass spectrometry (TWIM-MS) is shown to be able to separate and characterize several isomeric forms of diterpene glycosides stevioside (Stv) and rebaudioside A (RebA) that are cationized by Na(+) and K(+) at different sites. Determination and characterization of these coexisting isomeric species, herein termed catiomers, arising from cationization at different and highly competitive coordinating sites, is particularly challenging for glycosides. To achieve this goal, the advantage of using CO2 as a more massive and polarizable drift gas, over N2, was demonstrated. Post-TWIM-MS/MS experiments were used to confirm the separation. Optimization of the possible geometries and cross-sectional calculations for mobility peak assignments were also performed.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1002/jms.3532 | DOI Listing |
ACS Nano
December 2024
Institute of Molecular Plus, Tianjin University, Tianjin 300072, China.
Alloy nanocatalysts exhibit enhanced activity, selectivity, and stability mainly due to their versatile phases and atomic structures. However, nanocatalysts' "real" functional structures may vary from their as-synthesized status due to the structural and chemical changes during the activation and reaction conditions. Herein, we studied the activated CuPd/CeO nanocatalysts under the CO oxidation reaction featuring an atomic-scale phase separation process, resulting in a notable "hysteresis" in catalyst performance.
View Article and Find Full Text PDFPhys Rev E
November 2024
Dipartimento di Scienze Matematiche, Politecnico di Torino, Corso Duca degli Abruzzi 24, Turin, Italy and INFN, Sezione di Torino, Via P. Giuria 1, 10125 Turin, Italy.
The physical significance of the stochastic processes associated to the generalized Gibbs ensembles is scrutinized here with special attention to the thermodynamic fluctuations of small systems. Differently from the so-called stochastic thermodynamics, which starts from stochastic versions of the first and second law of thermodynamics and associates thermodynamic quantities to microscopic variables, here we consider stochastic variability directly in the macroscopic variables. By recognizing the potential structure of the Gibbs ensembles, when expressed as a function of the potential entropy generation, we obtain exact nonlinear thermodynamic Langevin equations (TLEs) for macroscopic variables, with drift expressed in terms of entropic forces.
View Article and Find Full Text PDFNanomaterials (Basel)
November 2024
School of Chemical and Environmental Engineering, Technical University of Crete, 73100 Chania, Greece.
The water-gas shift (WGS) reaction is one of the most significant reactions in hydrogen technology since it can be used directly to produce hydrogen from the reaction of CO and water; it is also a side reaction taking place in the hydrocarbon reforming processes, determining their selectivity towards H production. The development of highly active WGS catalysts, especially at temperatures below ~450 °C, where the reaction is thermodynamically favored but kinetically limited, remains a challenge. From a fundamental point of view, the reaction mechanism is still unclear.
View Article and Find Full Text PDFNanophotonics
November 2024
College of Science, China University of Petroleum (East China), Qingdao 266580, China.
Owing to its topological properties and band collapse, Floquet helical photonic lattices have gained increasing attention as a purely classical setting to realize the optical analogues of a wide variety of quantum phenomena. We demonstrate both theoretically and numerically that light propagation in an appropriately designed helical superlattice can exhibit spatial photonic Zitterbewegung effect, i.e.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Sonny Astani Department of Civil and Environmental Engineering, University of Southern California, Los Angeles, California 90089, United States.
In this paper, a concept of integrated CO capture and reverse water-gas shift (ICCrWGS) process was proposed using NH as the H carrier. The CO efficiency and total thermal energy consumption for the conventional rWGS, ICCrWGS using H (H-ICCrWGS) and NH (NH-ICCrWGS), were calculated. ICCrWGS using H and NH was conducted over the thermally stable Ni/CaZr dual-function materials (DFMs).
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!