J. Planar Chromatogr. 26, 445-451 (2013). HPTLC of telmisartan (1) and atorvastatin (2) on silica gel with methanol - chloroform 1:7. Quantitative determination by absorbance measurement at 280 nm. The hRf values for (1) and (2) were 64 and 27, respectively. Linearity was between 1.2-7.2 µg/zone for (1) and 0.4-2.4 µg/zone for (2). LOD and LOQ were 3 and 8 ng/zone. Recoveries (by standard addition) were 98-101 % for (1) and 99-101 % for (2). Intermediate intra- and inter-day precision was below 2 %. Comparable results were obtained with HPLC and UV methods.

J. Planar Chromatogr. 27, 333-339 (2014). TLC of alkaloids such as (1) papverine, (2) quinine, (3) berberine, (4) brucine, (5) emetine, (6) chelidonine, (7) boldine, (8) protopine and (9) allocryptopine on CN or RP18W phase with mixture of acetonitrile and water containing: acetic buffer at pH 3.6, 1 % acetic acid, 1 % ammonia, 0.01 M octane sulfonic acid sodium salt or methanol, and water containing 0.01 M diethylamine. On C18 plates, the best conditions for the separation of alkaloids were obtained with the mobile phase containing addition of octane sulfonic acid sodium salt, diethylamine, or aqueous ammonia; as for the CN plates, with aqueous eluents containing diethylamine or ammonia and nonaqueous eluent containing mixture of methanol, diidopropyl ether, and 2% ammonia. The efficiency of the system was increased by using a combination of two-dimensional thin-layer chromatography with multiple development chromatogram methods.

Food Chem. 239, 865-871 (2018). NIR spectroscopy for the analysis of oleic, palmitic, linoleic, linolenic, omega-3 and omega-6 acids, unsaturated and saturated fatty acids, and triacylglycerides was compared with HPTLC and GC methods. HPTLC of polar (1) and neutral (2) lipids in salmon oil on silica gel with methyl acetate – isopropanol – chloroform – methanol – potassium chloride (0.25 % solution) 25:25:25:10:9 for (1) and with n-hexane – diethyl ether – glacial acetic acid 35:15:1. Detection by dipping into primulin reagent (10 mg primuline, 40 mL water, 160 mL acetone) for 2 s. The NIR method permits the simultaneous quantification of several fatty acids, but the accuracy and robustness of the method remain at the screening level for palmitic and linolenic acids and monounsaterated fatty acids. The method is not sensitive enough to detect low concentrations of fatty acids, therefore direct measurements on salmon tissue samples were not considered. The NIR method requires a previous extraction of the lipids, similar to the chromatographic techniques. Still the NIR method is a fast, direct and not destructive technique for salmon oil sample screening purposes.

J. Chromatogr. Sci., 56 (9), 846–852 (2018). Simultaneous determination of theophylline (THP), guaifenesin (GUI) and guaiacol (GUA, a guaifenesin impurity) by HPTLC on silica gel with ethyl acetate – hexane – methanol - ammonia 65:35:10:2. Detection and quantification by densitometry at 275 nm. The hRf values were 13, 35 and 80 for THP, GUI and GUA, respectively. The linearity range was 0.4–2 μg/band for both THP and GUI, and 0.4–1.2 μg/band for GUA. Validation of the proposed method according to ICH guidelines. Statistical comparison of the results with RP-HPLC showed no difference regarding accuracy and precision.

(Hungarian). (N-demethylation of morphine alkaloids III. Some new reactions of the N-demethyl derivatives.). TLC on silica with benzene - methanol 8:2, chloroform - methanol 9:1 and chloroform - acetone - diethylamine 5:4:1. Visualization by UV or by Dragendorff reagent. Identified substances: N-demethylneopine, N-demethylneomorphine.

Anal. Chem. 58, 582-584 (1986). TLC of 9 racemic mixtures, 3 diasteomeric mixtures and 6 structural isomers on-cyclodextrin-bonded silica with methanol -1 % aqueous triethylammonium acetate (pH 4.1) 5:5. Detection under UV at 254 nm. Evaluation of different silica preparations.

(TLC chromatographic analysis for the quantitative estimation of the fecal bile acid composition). TLC of cholic acid, chenodesoxy cholic acid, desoxy cholic acid, lithocholic acid and ursodesoxy cholic acid on silica with isooctane - isopropanol - acetic acid 30:10:1 and/or isooctane - ethyl acetate - acetic acid 10:10:2. Derivatization with 2 % ethanolic solution of 2,7-dichlorofluoresceine. Densitometric quantification by fluorescence. Fiber rich polysaccharides (dietary fibers) elevate fecal bile acids and their metabolites. The possible role of this diet in relation to fecal bile acid concentration and large bowel cancer is discussed.

J. Chromatogr. 450, 443-447 (1988). TLC of cyclopiazonic acids on silica with ethyl acetate - methanol - conc. NH3 60:35:5. Detection under UV 254 nm. Comparison of the results with those obtained by CC on the same TLC silica. Also TLC of nutmeg oil on silica with petrol ether (80-100°C) - ether 8:2. Detection under UV or by exposure to iodine vapor.