Authors:Monika Waksmundzka-Hajnos, Mieczyslaw Hajnos, Ryszard Świeboda, and Anna Hawrył
Experimental results for the wicking process in a solid thin porous layer by liquids of different polarity with defined surface free energy components and viscosity has been considered theoretically. The method was used for determination of the solid surface free energy of the adsorbents used in thin layer chromatography. Experiments were performed on commercial glass plates precoated with silica, CN-silica, diol-silica, NH
-silica, and silanized silica with
-alkanes, diiodomethane, water, and formamide as mobile phases. Surface free energy components determined for investigated adsorbents were used for characterization and comparison of their surface properties.
Authors:Mieczysław Sajewicz, Łukasz Wojtal, Michał Hajnos, Monika Waksmundzka-Hajnos, and Teresa Kowalska
In a previous paper we discussed the possibility of fractionating the essential oils of different sage species by low-temperature preparative layer chromatography (PLC), followed by preparative isolation of the contents of each fraction and further analysis by GC-MS. In that way we attempted to emphasize the practical usefulness of lowtemperature planar chromatography for investigation of volatile compounds. In this study, we explore a possibility of fractionating essential oils contained in the different sage species by low-temperature analytical TLC followed by direct mass spectrometric analysis of the separated fractions. This objective can be achieved by TLC-MS with on-line transfer of the eluted fractions. The densitograms obtained from five different sage species (i.e.,
S. lavandulifolia, S. staminea, S. hians, S. triloba
) are compared. Each densitogram is accompanied by mass spectra recorded for each peak. Videoscans of the chromatograms are also presented. In this way multiple fingerprints of the analyzed plant material, each comprising a densitogram and a selection of mass spectra, were obtained. Advanced chemometric treatment of these multiple fingerprints can be used to reveal statistically significant differences between the plant species. Analytical and chemotaxonomic advantages and further aspects for this kind of approach are discussed.