Authors:Wojciech Markowski, Katarzyna Czapińska and Tomasz Baj
Retention of DNP derivatives of amino acids has been described by equations based on polynomial and
models. Models of retention were used to predict
values in simulation of multiple development chromatography in different modes and the values calculated were compared with those obtained experimentally. Beside the retention of solutes in MD TLC, the widths of the spots were also predicted and compared with those obtained experimentally. Assessments of proposed models of multiple development were verified by experimental results and estimated by statistical testing.
Authors:Aneta Hałka-Grysińska, Radosław Ł. Gwarda, Krzysztof Pawełek, Tomasz Baj and Tadeusz H. Dzido
Satisfactory separation of a test mixture of 19 dyes with a general elution problem was obtained by reversed-phase stepwise gradient thin-layer chromatography with single void volume of the mobile phase. An effect of the supplementary mobile phase flux to the surface of the adsorbent layer, observed previously, was eliminated. This improves the flow profile of the mobile phase and the shape of spots, and increases the repeatability of the results within the same plate and between studies. The experimental values of the relative zone/spot position, Rpg, showed good correlation with the results predicted by the computing calculation.
Authors:Tomasz Baj, Elwira Sieniawska, Agnieszka Ludwiczuk, Jarosław Widelski, Anna Kiełtyka-Dadasiewicz, Krystyna Skalicka-Woźniak and Kazimierz Głowniak
Essential oils obtained from Origanum species are characterized by high diversity in composition. In this work, thin-layer chromatography (TLC)—fingerprinting of Origanum species was performed for the first time and enabled the discrimination of three chemotypes (carvacrol, caryophyllene oxide, and terpineol/sabinyl). Gas chromatography—mass spectrometry and statistical analyses confirmed the presence of the mentioned chemotypes and deepened the characterization of the studied essential oils. TLC—bioautography showed that thymol and carvacrol are the main antioxidant compounds in Origanum sp. essential oils (EOs).