J Chromatogr A, 1603, 355–360 (2019). Samples were ethyl acetate root macerates of fully flowered Tanacetum vulgare (Asteraceae). HPTLC on silica gel (classical irregular particles vs. Lichrosphere with spherical particles) previously washed with methanol, dried for 5 min at room temperature, perimeter-sealed with a polymer coat, and heated for 30 min at 100 °C. Separation with toluene or with toluene – n-hexane 7:3, in classical capillary flow or in OPLC (overpressured layer chromatography). For OPLC, off-line infusion was used (closed mobile phase (MP) outlet, automatically stopping development); external pressure 50 bar, rapid MP flush 175 and 350 µL, MP flow rate 250 and 500 µL/min, 1830 and 3475 µL MP, development time 446 s and 424 s. Derivatization by immersion into vanillin – sulfuric acid reagent, followed by 5 min heating at 110 °C; or into PABA reagent (500 mg p-aminobenzoic acid, 18 mL glacial acetic acid diluted, 20 mL water, 1 mL o-phosphoric acid, 60 mL acetone), followed by 5 min heating at 140 °C. Effect-directed analysis using automated immersion: A) for free radical (DPPH•) scavengers; B) for activity against Gram-negative bacteria using Aliivibrio fischeri bioluminescence assay; C) for activity against Gram-positive bacteria with Bacillus subtilis bioassay. Four active polyynes were identified as hexadiynylidene-epoxy-dioxaspiro-decane (1), pontica epoxyde (nonene-triynyl-vinyl-oxirane) (2), tetradeca-triine-en-one (3) and trans-(hexadiynylidene)-dioxaspiro-decene (4), by hyphenating OPLC to quadrupole-orbitrap HRMS without eluent, using a DART interface (Direct Analysis in Real-Time, needle voltage 4kV, grid voltage 50 V, helium as gas, temperature 500 °C, full scan in positive ionization mode in m/z range 100-750). Polyynes (3) and (4) were coeluting in HPTLC but not in OPLC, demonstrating that (4) is not produced by oxidation during the DART-MS procedure. Separation with OPLC compared to HPTLC was performed in a shorter time and with better resolution at the same time. Layers with spherical particles gave higher resolution; zone distortions occurring in OPLC due to dissolved air in MP were prevented by previous MP sonication.

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. 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. 27, 80-83 (2014). HPTLC of methylene and rhodamine B on lanthanum fluoride particles (100 nm) with methanol - tetrahydrofuran 1:8. The mixture of methylene and rhodamine B is successfully separated by TLC on the lanthanum layer and the substances can be identified based on FTIR in situ spectra.

Chromatography the State of the Art, Vol. II, Akademiai Kiado, Budapest 1985, 517-534. Large pore silica (120 A) on glass support can be regenerated with strong acids + oxidizers followed by heating at high temperatures. Use of the layer material demonstrated with rat brain lipids chromatographed two-dimensionally with 1) chloroform - methanol - benzene NH3, 60:30:10:6 and 2) chloroform - methanol - acetone - benzene - acetic acid - water 70:30:5:10:4:1; with sea grass lipids using similar solvent systems and with polystyrenes separated with CCl4 - heptane - MEK 10:9:1.

J. Chromatogr. 357, 311-314 (1986). Description of a unit for preparing circular chromatographic plates at elevated temperatures. Silica G layer prepared with this device can be used repeatedly with ethyl acetate - methanol - water 104:72:26 as the solvent.

Chromatographia 23, 432-434 (1987). Discussion of TLC of carboxylic acids on barium sulfate - calcium sulfate in different proportions with various solvents.

J. Planar Chromatogr. 2, 119-127 (1989). Review on the use of calcium sulfate and mixtures of calcium sulfate with other inorganic adsorbents as separation layers in TLC. Analytes include inorganic ions, carboxylic acids, fatty acids, herbicides, lipids and related compounds.