Trends in Chromatography 8, 1-6 (2013). HPTLC of neutral lipids and a neutral lipid standard (consisting of 20 % each of cholesterol, oleic acid, triolein, methyl oleate, and cholesteryl oleate) on silica gel (HLF plates with 19 scored channels of 9 mm width) prewashed with dichloromethane - methanol 1:1 and heated for 30 min at 120 °C, with petroleum ether - diethyl ether - glacial acetic acid 80:20:1 with chamber saturation. Detection by spraying with 5 % ethanolic phosphomolybdic acid reagent and heating at 120 °C for 5 min. Neutral lipids appeared as blue zones on a yellow background. The fractions of free sterols, free fatty acids, triacylglycerols, methyl esters, and steryl esters were identified by comparison with the standard mixture. Quantification by absorption measurement at 610 nm via linear calibration (peak area).

PLoS ONE 10(10), e0140782 (2015). HPTLC of lipids, extracted from several cancerous cell lines by an adapted Bligh and Dyer’s method, on silica gel with chloroform – methanol 4:1. Detection under UV after spraying with thioflavine S (10 μg/mL in acetone 80 %), glycosylated lipids were hued in red-rose by spraying with orcinol 0.5 % in sulfuric acid 0.5 M followed by heating; some of those lipids were absent from the elisidepsin-resistant strains. These lipids were purified by scraping off the plate and by extracting with chloroform – methanol 2:1, then they were applied on a nitrocellulose membrane for an overlay assay for binding with an elisidepsin-biotin derivative (dot-blotting). One lipid was positive and was identified by NMR as probably a glucosylceramide.

CBS 116, 9-10 (2016). HPTLC of herbal slimming drugs and the standard orlistat on silica gel with toluene – ethyl acetate 4:1 with chamber saturation (with filter paper) to the migration distance of 70 mm. Detection by dipping in phosphomolybdic acid reagent (5 g in 100 mL ethanol) and heating at 110 °C for 5 min. Evaluation under UV 254 nm, 366 nm and white light. Quantitative determination by absorbance measurement at 195 nm before derivatization to detect illegally added orlistat in the herbal drugs. The LOD of orlistat standard was 70 ng/band.

CBS 119 (2017) 14-15. HPTLC of Cannabis sativa and standards cannabidiol (CBD), tetrahydrocannabinol (THC), and cannabinol (CBN) on silica gel with n-heptane – diethyl ether – formic acid 75:25:0.3 with chamber saturation for 20 min to a migration distance of 70 mm. Detection by spraying with Fast Blue salt B reagent (250 mg o-dianisidine bis(diazotized) zinc double salt in 10 mL water, 25 mL methanol and 15 mL dichloromethane), evaluation under white light. Quantitative determination by absorbance measurement at 210 nm prior to derivatization (for cannabinoid acids 285 nm). For the screening of THC-free samples the limit test can be used. The EU limit of 0.2 % is easily detected with or without detection. The %RSD of the assay prior to derivatization is 1.5 % and after derivatization 2.1 %. The LOD is 10 ng/zone.

Planta Med. 83(07), 661-671 (2017). Structural modifications of 9α- and 9β-hydroxyparthenolide (isolated from Anvillea radiata aerial parts) were performed either by Heck’s reaction (a palladium(II) acetate treatment in presence of triethylamine and iodoaryl in dimethylformamide), or by acylation (here, addition of aroyl chlorides and/or acetic anhydride in dichloromethane and pyridine). TLC for reaction monitoring of the 21 derivatives on silica gel with petroleum ether – ethyl acetate in various proportions (3:2; 1:4; 1:1). Detection under UV or under white light after spraying with 5 % phosphomolybdic acid in ethanol, followed by heating.

J. Planar Chromatogr. 3, 251-255 (1990). New layer for problematic separation: TLC of 10 organic acid herbicides on silica - calcium sulfate layers 1:4 with different solvent systems. Identification by spraying with alkaline ethanolic solution of bromophenol blue.

J. Planar Chromatogr. 3, 141-143 (1990). TLC of germanium-132 (mu-trioxo-bis(beta-carboxyethyl)germanic anhydride, organic germanium) on silica with propanol - conc. NH3 - water 15:3:5. Detection: After drying, immersion in a 0.05% phenylfluorone reagent solution for 2 s, drying and irradiation with artificial light at room temperature under 40-60 % rel. humidity for 4-6 h, spots become yellow. Visualization under UV 366 nm (bright yellow fluorescence). Quantification by fluorescence at 366 nm. Detection limit 100 ng.

II. Multidevelopment technique. J. Planar Chromatogr. 4, 91-92 (1991). HPTLC of 21 different lipid components on silica with the following mobile phases: 1) propanol – methyl acetate – methanol – ethanol – 43 mM KCl 23:23:29:10:12; 2) hexane – acetone – toluene – chloroform 300:54:25:25; 3) tetrachloromethane. Detection with phosphomolybdic acid reagent (for polar lipids), and CuSO4 (for neutral lipid compounds, glycerides and fatty acids). 1. Publication: L. KOVACS, J. PICK, J. PUCSIK, J. Planar Chromatogr. 2, 389-391 (1989).