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).

J. Planar Chromatogr. 4, 373-378 (1991). Screening for 78 drugs visualizable with Fast Black K salt, including 25 amphetamine type drugs, on silica with toluene – acetone – ethanol – NH3 45:45:7:3 and on RP-18 with methanol – water – hydrochloric acid 50:50:1. Classification of the drugs into two groups (violet and red) according to color. Evaluation of the TLC/RPTLC combination for identification, in both color groups, with the mean list length method.

J. Planar Chromatogr. 6, 129-137 (1993). HPTLC of vanilla extracts and reference substances on silica with chloroform - ethyl acetate - propan-1-ol 96:2:2 or 94:2:2; detection by postchromatographic derivatization with 2,4-DNPH in 25 mL 95% ethanol and 25 mL of 85% orthophosphoric acid for about 5 sec. Quantification by densitometry (absorbance at 280 nm). A simple method with a high sample throughput.