Isotopic Effect in the Separation of Polystyrene by Normal Phase and Reversed Phase Liquid Chromatography

Kim, Young‐Tak; Ahn, Seonyoung; Chang, Taihyun

doi:10.1021/ac902622t

Cited by 20 publications

(16 citation statements)

References 29 publications

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“…Both interactions are based on the electrostatic force. We can derive the temperature dependence from the application of van’t Hoff’s equation for chromatography, , where Δ H and Δ S are alterations of the enthalpy and entropy, respectively, in the chromatographic partition equilibrium. Thus, the differences in Δ H TIE and Δ S TIE between protiated and deuterated compounds (ΔΔ H TIE , ΔΔ S TIE ) could be obtained.…”

Section: Resultsmentioning

confidence: 99%

Tunable Liquid Chromatographic Separation of H/D Isotopologues Enabled by Aromatic π Interactions

et al. 2020

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We report hydrogen/deuterium (H/D) isotope effects based on weak intermolecular interactions with polar functional groups and aromatic rings in liquid chromatography (LC). Various LC experiments with different aromatic analytes, separation media, and nonpolar mobile phases were conducted under normal phase LC conditions, where the hydrophobic interaction was completely suppressed. The separation media that had polar functional groups, such as silanol groups, allowed for higher separation efficiencies for the pairs of aromatic H/D isotopologues. In comparing the 13C NMR spectra of protiated and deuterated aromatic analytes, the electron density of the deuterated analyte was found to be slightly higher than that of the protiated analytes. In the case of silanol functional groups, aromatic rings of the analyte acted as donors through the OH−π interaction to hydrogen atoms in the silanol groups. Thus, the deuterated analytes were able to be greatly retained by the stronger OH-π interactions. Furthermore, a C70-fullerene bonded monolithic column (C70 column), which effectively provides CH−π interactions, allowed the opposite isotope effect. Briefly, an electrostatic attraction based on the dipole-(induced) dipole interaction dominated in the CH−π interactions, according to a van’t Hoff analysis. Hence, the bonding lengths of the C–H or D bonds were sensitively affected, such that we were able to conclude that the CH−π interaction depended on the geometric effect. Applying these opposing H/D isotope effects, we were able to finally demonstrate effective H/D isotopologue separations by utilizing the complementary action of the OH−π and CH-π interactions.

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Section: Resultsmentioning

confidence: 99%

Tunable Liquid Chromatographic Separation of H/D Isotopologues Enabled by Aromatic π Interactions

et al. 2020

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“…Utilization of deuterium atoms during the synthesis of the isotope‐coded compounds often complicates chromatographic separation due to the isotopic effect . However, according to solvophobic theory, the probability of deuterium atom interaction with a stationary phase during chromatographic separation is reduced by placing it next to a hydrophilic group (such as quaternary ammonium center) that has little to no affinity to the stationary phase in RP‐HPLC .…”

Section: Resultsmentioning

confidence: 99%

Quaternary ammonium isobaric tag for a relative and absolute quantification of peptides

2017

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Isobaric labeling quantification of peptides has become a method of choice for mass spectrometry-based proteomics studies. However, despite of wide variety of commercially available isobaric tags, none of the currently available methods offers significant improvement of sensitivity of detection during MS experiment. Recently, many strategies were applied to increase the ionization efficiency of peptides involving chemical modifications introducing quaternary ammonium fixed charge. Here, we present a novel quaternary ammonium-based isobaric tag for relative and absolute quantification of peptides (QAS-iTRAQ 2-plex). Upon collisional activation, the new stable benzylic-type cationic reporter ion is liberated from the tag. Deuterium atoms were used to offset the differential masses of a reporter group. We tested the applicability of QAS-iTRAQ 2-plex reagent on a series of model peptides as well as bovine serum albumin tryptic digest. Obtained results suggest usefulness of this isobaric ionization tag for relative and absolute quantification of peptides.

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“…They found, however, that the differences in retention times were not sufficient to separate deuterated and hydrogeneous polystyrene (d‐PS and h‐PS) of similar molar masses with the deuterated polymers being retained less than their hydrogenous analogs. Kim et al used RPLC and normal phase LC and examined the retention of d‐PS relative to h‐PS. Ahn et al reported on the characterization of comb‐shaped polystyrene, where d‐PS branches were attached to the hydrogeneous backbone.…”

Section: Microstructure Analysis By Column‐based Fractionationsmentioning

confidence: 99%

Advanced fractionation methods for the microstructure analysis of complex polymers

Pasch

2015

Polymers for Advanced Techs

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This review discusses some recent work on the microstructure analysis of complex polymers using advanced fractionation methods. Complex polymers are distributed in a number of molecular parameters including molar mass, chemical composition, molecular architecture, and microstructure. Molar mass and chemical composition analysis is typically conducted by a range of spectroscopic and chromatographic methods, size exclusion chromatography and high-performance liquid chromatography (HPLC) being the most important fractionation methods. It is shown that HPLC is also very sensitive regarding polymer microstructure and can be used for the fractionation of e.g. polymethacrylates, polyisoprene, and polybutadiene. The best approach to the quantitative analysis of microstructure distributions is the on-line coupling of the fractionation with 1 H nuclear magnetic resonance spectroscopy. The spectroscopic analysis of chromatographic fractions provides concentration profiles of the tactic units as a function of the chromatographic separation and can be used for both HPLC and size exclusion chromatography. Apart from column-based fractionations, channel-based fractionations such as thermal field flow fractionation are powerful tools for microstructure analysis of complex polymers. It has been shown very recently that thermal field flow fractionation is capable of fractionating polyisoprene and polybutadiene according to microstructure.

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Isotopic Effect in the Separation of Polystyrene by Normal Phase and Reversed Phase Liquid Chromatography

Cited by 20 publications

References 29 publications

Tunable Liquid Chromatographic Separation of H/D Isotopologues Enabled by Aromatic π Interactions

Tunable Liquid Chromatographic Separation of H/D Isotopologues Enabled by Aromatic π Interactions

Quaternary ammonium isobaric tag for a relative and absolute quantification of peptides

Advanced fractionation methods for the microstructure analysis of complex polymers

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