title: Inversion of type of separation system in planar chromatography of peptides, using C18 silica-based adsorbents.
abstract: Our previous results show, that C18 silica-based adsorbents used in high-performance thin-layer chromatography (HPTLC), provide complex retention mechanism basing on various polar and nonpolar interactions. Here we present, that in chromatography of peptides, due to mixed-mode properties of these adsorbents, there is a simple way to obtain inversion of separation system type (from reversed-phase, RP, to normal-phase, NP, and vice versa). The results presented provide detailed information how to obtain inversion mentioned and reflect the extent (the type and concentration of organic solvent, the type and concentration of ion-pairing reagent in the mobile phase) of this phenomenon. We show, that the system type inversion results in significant change of selectivity of separation, which may be especially useful in 2D separation of complex samples of basic/amphoteric compounds such as peptides. This results from the fact, that C18 silica-based HPTLC adsorbents, may be used in hydrophilic interaction chromatography (HILIC) or RP chromatography, in dependence on mobile phase composition.
authors.affiliation: Department of Physical Chemistry, Chair of Chemistry, Faculty of Pharmacy with Medical Analytics Division, Medical University of Lublin, 4a Chodźki St., 20-093 Lublin, Poland. Electronic address: radoslaw.gwarda@umlub.pl.
authors.forename: Radosław Ł
authors.initials: RŁ
authors.lastname: Gwarda
authors.affiliation: Chair and Department of Synthesis and Chemical Technology of Pharmaceutical Substances, Faculty of Pharmacy with Medical Analytics Division, Medical University of Lublin, 4a Chodźki St., 20-093 Lublin, Poland.
authors.forename: Monika
authors.initials: M
authors.lastname: Aletańska-Kozak
authors.affiliation: Chair and Department of Synthesis and Chemical Technology of Pharmaceutical Substances, Faculty of Pharmacy with Medical Analytics Division, Medical University of Lublin, 4a Chodźki St., 20-093 Lublin, Poland.
authors.forename: Dariusz
authors.initials: D
authors.lastname: Matosiuk
authors.affiliation: Department of Physical Chemistry, Chair of Chemistry, Faculty of Pharmacy with Medical Analytics Division, Medical University of Lublin, 4a Chodźki St., 20-093 Lublin, Poland.
authors.forename: Tadeusz H
authors.initials: TH
authors.lastname: Dzido
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000295:instrumentation* / Q000379:methods*; D002855:Chromatography, Thin Layer; D057927:Hydrophobic and Hydrophilic Interactions; D009930:Organic Chemicals; D010455:Peptides / Q000032:analysis / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry
chemical_list: D009930:Organic Chemicals; D010455:Peptides; D012997:Solvents; D012822:Silicon Dioxide
keywords: Inversion of separation system type; Mixed mode chromatography; Peptide separation; Retention mechanism; Thin-layer chromatography