Cation-exchange stationary phases were characterized in different chromatographic modes (HILIC, RPLC, IC) and applied to the separation of non-charged hydrophobic and hydrophilic analytes. The set of columns under investigation included both commercially available cation-exchangers and self-prepared PS/DVB-based columns, the latter consisting of adjustable amounts of carboxylic and sulfonic acid functional groups. The influence of cation-exchange site and polymer substrate on the multimodal properties of cation-exchangers was identified using selectivity parameters, polymer imaging and excess adsorption isotherms. Introducing weakly acidic cation-exchange functional groups to the unmodified PS/DVB-substrate effectively reduced hydrophobic interactions, whilst a low degree of sulfonation (0.09 to 0.27% w/w sulphur) mainly influenced electrostatic interactions. Silica substrate was found to be another important factor for inducing hydrophilic interactions. The presented results demonstrate that cation-exchange resins are suitable for mixed-mode applications and offer versatile selectivity.
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http://dx.doi.org/10.1016/j.chroma.2023.463934 | DOI Listing |
J Chromatogr A
January 2025
Genetics Guided Dementia Discovery (G2D2), Eisai, Inc. 35 Cambridge Park Drive, Suite 200, Cambridge, MA, 02140, USA.
The current study investigates the use of mixed-mode chromatography as a combination of anion-exchange (AEX) and hydrophobic interaction chromatography (HIC) for the analysis and purification of single-stranded antisense oligonucleotides with stereo-controlled phosphorothioate inter- nucleotide linkages. Initially a Scherzo-SS-C18 trimodal stationary phase with reversed-phase/AEX/ cation-exchange (CEX) functionalities is systematically evaluated to reveal the presence of U-shaped retention composed of two retention modes namely AEX and HIC, where the latter was also observed on related trimodal Scherzo SM and SW analogues. For the first time, retention and separation of deprotected oligonucleotides was described on a single mixed-mode column using a combination of AEX and HIC.
View Article and Find Full Text PDFJ Chromatogr A
January 2025
Ministry of Education, Engineering Research Center of Pharmaceutical Process Chemistry, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, PR China; Key Lab of Separation Science for Analytical Chemistry, Key Lab of Natural Medicine, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning Province 116023, PR China.
This study demonstrates the expanded application of ion-exchange stationary phases (including strong cation exchange, SCX and strong anion exchange, SAX) in supercritical fluid chromatography (SFC), and more importantly, provides a deeper understanding of the retention mechanisms of these two stationary phases when using the same acidic additive. Phenylpropionic acid compounds (belonging to phenolic acids) were selected as probes. On the SCX column, the π-π and polar interactions originating from the bonded benzenesulfonic acid groups were important foundations for prolonging the retention time of solutes, but they were also the main reason for solutes' tailing profiles.
View Article and Find Full Text PDFJ Sep Sci
November 2024
College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, China.
Using poly(styrene-divinylbenzene) microspheres as stationary phase matrix and mercaptosuccinic acid as a modifier, a new weak cation exchange resin was synthesized by thiol click reaction. The conditions for thiol-chlorine click reaction and thiol-alkene click reaction were optimized. The surface morphology and chemical composition of the modified microspheres were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, and an elemental analyzer.
View Article and Find Full Text PDFMolecules
July 2024
Analytical Chemistry Research Group, University of Pannonia, Egyetem utca 10, H-8200 Veszprém, Hungary.
Appl Radiat Isot
September 2024
Research Center for Nuclear Fuel Cycle and Radioactive Waste Technology- Research Organization for Nuclear Energy (ORTN), National Research and Innovation Agency (BRIN), Indonesia.
The P radioisotope, with a half-life of 14.3 days and an energy level of 1.71 MeV, has diverse applications in medicine and research.
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