title: Investigation of the temperature dependence of water adsorption on silica-based stationary phases in hydrophilic interaction liquid chromatography.
abstract: In the present work, the adsorption of water was investigated in aqueous normal-phase liquid chromatography on Cogent Silica C and Cogent Phenyl hydride stationary phases at different temperatures by frontal analysis - using coulometric Karl Fischer titration - to compare the temperature dependence of adsorption of water from aqueous acetonitrile. The Cogent Silica-C and Cogent Phenyl Hydride columns have a silicon hydride surface (silica hydride) with less than 2% free silanol group; therefore, they do not have a strong association with water. The adsorption behavior of water on the mentioned stationary phases was modeled by Langmuir isotherm. The preferentially adsorbed water was expressed in terms of a hypothetical monomolecular water layer equivalent in the inner pores. The uptake of water slightly depends on the temperature. The adsorbed water may fill four to eight percent of the pore volume over the studied temperature range, which approximately corresponds to the equivalent of 0.24-0.68 water layer coverage of the adsorbent surface. The phenyl hydride stationary phase shows decreased water uptake in comparison to the Silica C stationary phase.
authors.affiliation: Department of Analytical and Environmental Chemistry and Szentágothai Research Center, University of Pécs, Ifjúság útja 6, H-7624 Pécs, Hungary.
authors.forename: Endre
authors.initials: E
authors.lastname: Bartó
authors.affiliation: Department of Analytical and Environmental Chemistry and Szentágothai Research Center, University of Pécs, Ifjúság útja 6, H-7624 Pécs, Hungary; MTA-PTE Molecular Interactions in Separation Science Research Group, Ifjúság útja 6, H-7624 Pécs, Hungary. Electronic address: felinger@ttk.pte.hu.
authors.forename: Attila
authors.initials: A
authors.lastname: Felinger
authors.affiliation: Department of Analytical Chemistry, University of Pardubice, Studentská 573, CZ-532 10 Pardubice, Czechia.
authors.forename: Pavel
authors.initials: P
authors.lastname: Jandera
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000327:Adsorption; D002851:Chromatography, High Pressure Liquid; D057927:Hydrophobic and Hydrophilic Interactions; D017640:Silicates / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D000097:Acetonitriles; D017640:Silicates; C487012:silica hydride; D014867:Water; D012822:Silicon Dioxide; C032159:acetonitrile
keywords: Aqueous normal phase liquid chromatography; HILIC; Karl Fischer titration; Water adsorption