Rapid Commun. Mass Spectrom. 34, 8631 (2020). A 3D-printed, fully automated, open-source add-on user interface was built for elution-head-based TLC/HPTLC-MS. The system allowed a very compact plate-positioning system combined with an image-based software solution providing a platform to control and synchronize all steps from positioning, elution, advanced cleaning to MS data acquisition.

J. Liq. Chromatogr. Relat. Technol. https://doi.org/10.1080/10826076.2021.1933025 (2021). Laser fabrication of open capillary microchannels on cyclic olefin polymer susbtrates as stationary phase. Microchannels of 24 µm X 68 µm depth were produced using a neodymium-doped yttrium aluminum garnetan laser (Nd:YAG). The ultra thin layer chromatography layer was used for the separation of Fast Green for food coloring (1) and rhodamine 6G (2) and compared with a comercial RP-TLC. The hRF values for (1) and (2) were 9 and 18 using the UTLC plate and 10 and 57 with the RP-TLC plate. The paper highlighted the potential to tailor the surface chemistry through known surface functionalization routes for cyclic olefin polymer susbtrates that will allow unique applications for the UTLC plate.

J. of Chromatogr. Sci. 58 (4), 323 - 333 (2020). Application of TLC to evaluate the lipophilicity of triterpenes, newly synthesized betulin and betulone derivatives with anticancer activity, in order to find the correlation between theoretically and experimentally calculated values of lipophilicity and the structure of compounds. Investigation of the relationships between lipophilicity and pharmacokinetic parameters or anticancer activity. Similarity analysis was performed to divide the compounds into groups regarding their use as suitable medicine substances. Study of the differences in the compounds grouping in relation with the values of lipophilicity calculated by computer software or obtained by TLC through cluster analysis, clearly shows that the theoretically calculated values of lipophilicity are strongly connected to the structure of the compounds.

J. Liq. Chromatogr. Relat. Technol. 43, 319-327 (2020). Review of impregnated agents used in TLC and their applications in analytical and medicinal chemistry. Impregnation with inorganic ions, chelating reagents, lipophilic substances, surfactants, chiral selectors and ionic liquids were discussed.

J. Liq. Chromatogr. Relat. Technol. 43, 414-423 (2020). HPTLC fingerprint of Ganoderma lucidum fruiting body on silica gel with toluene - tetrahydrofuran - acetic acid 70:30:1. Detection by dipping into a solution of 10% sulfuric acid in methanol, followed by heating at 100 ºC for 3 min. Qualitative determination under UV light at 254 and 366 nm. The hRF values for ganoderic acids D, B, A, G and C2 were in the zone between 10 and 50. This zone was used for quantification of total triterpene acids by absorbance measurement at 260 nm. Linearity of each of the main peaks between hRF 10 to 50 was determined. The linear range of ganoderic acid A was between 200 and 500 ng/zone.  The study proposes a new method for evaluation, based on “comprehensive high-performance thin layer chromatography (HPTLC) fingerprinting.” Instead of several different methods using different chromatographic techniques, a single HPTLC analysis for identification of Ganoderma lucidum fruiting body with a test for adulteration and quantitative determination of the content of total triterpene acids is proposed. As an alternative to the current tests in the  USP monograph on G. lucidum fruiting body this HPTLC method is a single, low-cost test, which eliminates the UHPLC assay of total triterpene acids.

J. Liq. Chromatogr. Relat. Technol. 43, 300-304 (2020). HPTLC of thymol, carvacrol and linalool in Solidago canadensis on silica gel with n-hexane - acetone 4:1. The method was compared with bilateral band compression (BBC) of the 10 mm wide lanes of HPTLC separation, resulting in more than 6 times increase in peak height and peak area. In BBC a solvent flow perpendicular to the direction of chromatogram development squeezes the chromatographic bands into a smaller area The method improved detection sensitivity of sample components with low abundance.

J. of Chromatogr. A 1591, 162-170 (2019). TLC of malachite green (1) and fast green (2) on diatom biosilica (a nanostructured, porous stationary phase composed of randomly-deposited biosilica frustules isolated from living cells of diatom Pinnularia sp.) instead of conventional silica gel with 1-butanol - ethanol - water 9:1:1 and 1-butanol - acetic acid - water 5:1:2. Diatom biosilica reduced the flow velocity and permeability constant by a factor two compared to silica gel and thus improved the resolution of (1) and (2). The theoretical plate height for both analytes was reduced ten-fold with 1-butanol - acetic acid - water 5:1:2, and the difference in retention time between malachite green and fast green was increased (ΔhRF 26) with 1-butanol - ethanol - water 9:1:1.

J. Planar Chromatogr. 32, 197-203 (2019). HPTLC of equol (1), artemisinin (2) and caffeine (3) on silica gel with methyl t-butyl ether - cyclohexane 1:1 for (1), cyclohexane - ethyl acetate 7:3 for (2) and ethyl acetate - acetone 7:3 for (3). The plate was scanned with a DART–TOF MS system to optimize the measurement conditions. The hRF values for (1) to (3) were 71, 63 and 53, respectively. LOD and LOQ were 1.2 and 1.8 µg/zone for (1), 225 and 315 ng/zone for (2) and 270 and 490 ng/zone for (3), respectivley.