J. Planar Chromatogr. 30, 481-487 (2017). HPTLC of pantoprazole sodium sesquihydrate (1), metronidazole (2) and clarithromycin (3) on silica gel with ethyl acetate and absolute ethanol (3:1) ‒ heptane ‒ 33 % ammonia 14:5:1. Quantitative determination by absorbance measurement at 280 nm. The hRF values for (1) to (3) were 49, 72 and 83, respectively. Linearity was between 0.8 and 8 μg/zone for (1), 4 and 40 μg/zone for (2) and 5 and 50 μg/zone for (3). LOD and LOQ were 153 and 462 ng/zone for (1), 760 and 2310 ng/zone for (2) and 880 and 2670 ng/zone for (3), respectively. The intermediate/interday/intra-day precision was below 2 % (n=3). Average recovery was 99.6 % for (1), 99.8 % for (2) and 100.1 % for (3).

Separations 5, 1-11 (2018). HPTLC of lipid content in yeast (clonal prion-infected and prion-free cells) on silica gel with 1) petroleum ether – diethyl ether – glacial acetic acid 80:20:1 for free sterols, free fatty acids, and triacylglycerols, 2) hexane – petroleum ether – diethyl ether – glacial acetic acid 50:20:5:1 for steryl esters, methyl esters, and squalene and 3) chloroform – diethyl ether – acetic acid 130:50:9 for phospholipids (phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositol). Detection of neutral lipids by spraying with 5 % phosphomolybdic acid in ethanol, followed by heating at 120 °C for 30 min. Detection of phospholipids by spraying with 10 % cupric sulfate in 8 % phosphoric acid, followed by heating at 140 °C for 30 min. Evaluation at 370 nm (deuterium lamp) for phospholipids and at 610 nm (halogen-tungsten lamp) for neutral lipids. The hRf values for neutral lipids were 10 for cholesterol, 33 for oleic acid and 51 for triolein as well as 41 for methyl oleate, 56 for cholesteryl oleate and 77 for squalene. The hRf values of phospholipids were 21 for phosphatidylinositol, 27 for phosphatidylethanolamine and 48 for phosphatidylcholine. HPTLC demonstrated to be a powerful tool for revealing subtle changes in the physiology of yeast.

J. Chromatogr. A 1533, 199-207 (2018). Presentation of a simple and cost-effective approach for the determination of selenium species in algae and yeast biomass by TLC combined with diode laser thermal vaporization inductively coupled plasma mass spectrometry (DLTV ICP MS), after extraction of freeze-dried biomass in 4M methanesulphonic acid and vaporization of the selenium species from cellulose plates using a continuous-wave infrared diode laser with power up to 4W. Quantification of selenomethionine and selenocysteine with LOD of 3 μg/L in a Se-enriched microalgae Chlorella vulgaris and yeast certified reference material SELM-1. Comparison of the results delivered by TLC-DLTV ICP MS with those obtained by a routine coupling of HPLC to ICP MS showed that both were consistent, moreover, the TLC approach has advantage in capability of analyzing extract containing even undiluted crude hydrolysates.

J. Liq. Chromatogr. Relat. Technol. 41, 364-372 (2018). TLC-DPPH test of gluten-free sheeted pasta supplemented with pomegranate seeds powder (PSP) on silica gel with ethyl acetate – water – acetic acid 8:1:1. Plates were immersed for 5 s in a freshly prepared 0.1 % methanolic DPPH solution and scanned every 10 min over an hour. The total areas under the peaks per track were measured and compared with the area obtained for rutin. Antioxidant properties of gluten free pasta correlated with the PSP content.

J. Chromatogr. A 1569, 212-221 (2018). Presentation of a method for simultaneous determination of mono-, di-, oligo- and polysaccharides in food by HPTLC on silica gel with acetonitrile – water 4:1 containing 3.6 mM natural products reagent A in a single development. Use of the method for both, effective food screening and quantification for up to 20 samples in parallel on the same plate with good reproducibility of the separation at control of the layer activity, and with the determination coefficients of the calibration curves between 0.9980 and 0.9998. Test of the method with 4 different prebiotic food and 60 naturally degraded inulin samples proved its advantages of minimal sample preparation along with the determination of the intact inulin and FOS allowed the evaluation of the natural inulin degradation profile, as shown for naturally degraded inulin samples, and the method is robust and suitable for routine analysis, especially in food control, as well as might be of interest in other fields, e.g. plant breeding, edible insects, functional feed and metabolic processes.

J. AOAC Int. 101, 1397-1401 (2018). HPTLC of sudan red dyes, namely Sudan orange G (1), Sudan red G (2), Sudan I (3), Sudan II (4), Sudan III (5) and Sudan IV (6) in spices and spice mixtures on RP-18 acetonitrile – methanol – aqueous ammonia solution (25 %) 40:9:1. Quantitative determination using a flatbed scanner with a 16-bit resolution. The hRF values for (1) to (6) were 54, 48, 57, 35, 26 and 17, respectively. Linearity was between 20 and 500 ng/zone for (1) to (6). LOD and LOQ were 17 and 35 ng/zone for (1), 11 and 21 ng/zone for (2), 14 and 31 ng/zone for (3), 12 and 24 ng/zone for (4), 18 and 42 ng/zone for (5) and 16 and 37 ng/zone for (6), respectively.

J. High Resol. Chromatogr. 7, 473-476 (1984). HPTLC of phospholipids on silica with chloroform - acetone - methanol - acetic acid - water 3:4:1:1:0.6. Detection by dipping into MnCl2-reagent and heating at 120 °C for 20 minutes, after cooling down dipping into paraffin-hexane 1:2 and drying. In situ fluorometry.

Proc. Intern. Symposium on TLC with special Emphasis on OPLC, Szeged, 24-25 (1984). HPTLC of papaverine hydrochloride on silica with diisopropyl ether - isooctane 1:1, diisopropyl ether - methanol 1:1. Quantification by fluorescence scanning (263 nm excitation).