A hydrophilic interaction liquid chromatography (HILIC) stationary phase was prepared by a two-step synthesis method, immobilizing polyacrylamide on silica sphere particles. The stationary phase (named PA, 5μm dia) was evaluated using a mixture of carbohydrates in HILIC mode and the column efficiency reached 121,000Nm. The retention behavior of carbohydrates on PA stationary phase was investigated with three different organic solvents (acetonitrile, ethanol and methanol) employed as the weak eluent. The strongest hydrophilicity of PA stationary phase was observed in both acetonitrile and methanol as the weak eluent, when compared with another two amide stationary phases. Attributing to its high hydrophilicity, three oligosaccharides (xylooligosaccharide, fructooligosaccharide and chitooligosaccharides) presented good retention on PA stationary phase using alcohols/water as mobile phase. Finally, PA stationary phase was successfully applied for the purification of galactooligosaccharides and saponins of Paris polyphylla. It is feasible to use safer and cheaper alcohols to replace acetonitrile as the weak eluent for green analysis and purification of polar compounds on PA stationary phase.
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http://dx.doi.org/10.1016/j.chroma.2017.10.005 | DOI Listing |
Anal Chem
January 2025
Department of Engineering and Chemical Sciences, Karlstad University, SE-651 88 Karlstad, Sweden.
This work introduces the Adsorption Energy Distribution (AED) calculation using competitive adsorption isotherm data, enabling investigation of the simultaneous AED of two components for the first time. The AED provides crucial insights by visualizing competitive adsorption processes, offering an alternative adsorption isotherm model without prior assuming adsorption heterogeneity, and assisting in model selection for more accurate retention mechanistic modeling. The competitive AED enhances our understanding of multicomponent interactions on stationary phases, which is crucial for understanding how analytes compete on the stationary phase surface and for selecting adsorption models for numerical optimization of preparative chromatography.
View Article and Find Full Text PDFAnal Chem
January 2025
Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, 500 05 Hradec Králové, Czechia.
The retention behavior in supercritical fluid chromatography (SFC) remains a complex and poorly understood phenomenon despite the development of various models to explain retention mechanisms. This study aims to deepen the understanding of retention by investigating three distinct stationary phases: high-strength silica octadecyl (HSS C18 SB), charged surface hybrid pentafluorophenyl (CSH PFP), and porous graphitic carbon (PGC) as a nonsilica-based phase. Three mobile phase compositions, i.
View Article and Find Full Text PDFAnal Chim Acta
February 2025
School of Chemistry and Chemical Engineering, Qiannan Normal University for Nationalities, Duyun, 558000, China.
New stationary phases including polar embedded stationary phases that are capable of utilising green mobile phases have recently emerged. This study presents two straightforward strategies for preparing C18 phases with distinct polar-embedded groups: thioether (C18) and quaternary ammonium (C18). The two strategies were assessed based on convenience, cost, yield, and time efficiency.
View Article and Find Full Text PDFIEEE/ACM Trans Audio Speech Lang Process
February 2024
CRSS: Center for Robust Speech Systems; Cochlear Implant Processing Laboratory (CILab), Department of Electrical and Computer Engineering, University of Texas at Dallas, USA.
The presence of background noise or competing talkers is one of the main communication challenges for cochlear implant (CI) users in speech understanding in naturalistic spaces. These external factors distort the time-frequency (T-F) content including magnitude spectrum and phase of speech signals. While most existing speech enhancement (SE) solutions focus solely on enhancing the magnitude response, recent research highlights the importance of phase in perceptual speech quality.
View Article and Find Full Text PDFJ Pharm Biomed Anal
January 2025
ADSI, Austrian Drug Screening Institute GmbH, Innrain 66a, Innsbruck 6020, Austria.
The aim of this work was to develop and validate a rapid dispersive-solid-phase extraction method for the quantification of pyrrolizidine alkaloids (PA) from plant extracts. The method was focused on the significant removal of the intricate matrix to ensure good sensitivity for the subsequent instrumental analysis of PA. This was achieved by employing nano-zirconium silicate (NZS) as a dispersive-SPE sorbent.
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