CBS 93, 10-12 (2004). HPTLC of progesterone on silica gel prewashed by development in AMD2 first with chloroform - methanol 1:1 and then with the mobile phase, followed by drying at 80 °C for 15 min. Development in AMD2 with toluene - 2-propanol 10:1 without preconditioning over 60 mm. Quantitative determination by absorbance measurement at 252 nm followed by spectra recording from 200 to 360 nm. The linear working range is 25.7-154.5 ng/zone. Repeatability (standard deviation calculated from the amounts of seven simulated progesterone samples determined on the same plate at three concentration levels in the lower, middle and upper range) is 0.26-1.29 %. Recovery is 99.88-100.97 %. Reproducibility was performed with recycled HPTLC plates.

J. Planar Chromatogr. 30, 423-426 (2017). 2D-HPTLC of phytoestrogenic active compounds in the root of Glycyrrhiza glabra on RP-18 with hexane – ethyl acetate – acetone 9:3:2 in the first direction and acetone – water 3:2 in the second direction. Effect-direct analysis by dipping into a yeast suspension followed by incubation at 30 °C for 4 h, drying at 37 °C for 15 min and spraying with the combined reaction buffer C (20 mL reaction buffer C is mixed with 0.2 mL of a freshly prepared solution of 0.05 g/mL 4-methylumbelliferyl-ß-D-galactopyranoside in DMSO or 0.2 mL of a freshly prepared solution of 0.05 g/mL 5-bromo-4-chloro-3-indoxyl-ß-D-galactopyranoside (X-Gal) in DMSO). Fluorescence detection at UV 366 nm._x000D_

Sz. Nyiredy, A. Kakuk (eds.): Planar Chromatography 2000, Lillafüred, Hungary, 24-26 June 2000, Res. Inst. for Med. Plants, p. 19-25. OPLC of ethinyl estradiole on silica gel with cyclohexane - ethyl acetate - chloroform 3:1:1. Detection by spraying with sulfuric acid and visual evaluation at 366 nm. The method is compared with the Official British and European Pharmacopoeia monographs. Only with the OPLC method it was possible to separate all impurities, i.e. 6-hydroxy derivatives (both isomers), the oxo-derivatives (6-oxo- and 16-oxo-), the 9(11)-dehydro and the 17-epi-derivatives from the estrone and estradiol. The HPLC method of the 3rd European Pharmacopoeia has to be changed slightly in order to analyze all impurities. The British Pharmacopoeia TLC method was not suitable because of its poor selectivity. Both OPLC and HPLC are suitable for purity testing. The OPLC method was preferred for process-validation because it shows a short analysis time and low eluent consumption (tenfold less than HPLC). The HPLC method was used for critical batches due to its better precision (3,5% RSD).

J. Sep. Sci. 38, 4021-4028 (2015). HPTLC of eight natural products viz. stigmasterol (1), oleanolic acid-3-acetate (2), oleanolic acid (3), biochanin A (4), genistein (5), pratensein (6), chrysoeriol (7), and luteolin (8) in Cicer microphyllum on silica gel with n-hexane - ethyl acetate - formic acid 90:65:8. Detection by dipping into a solution of cerric ammonium sulfate reagent, followed by heating at 105 °C for 5 min. Quantitative determination by absorbance measurement at 366 nm. The hRF values for compounds (1) to (8) were 98, 89, 78, 70, 63, 42, 33 and 4, respectively. Linearity was in the range of 100-800 ng/zone for (1) to (8). LOD and LOQ were 60 and 90 ng/zone for (1), (5) and (8), 50 and 90 ng/zone for (2), 90 and 110 ng/zone for (3), 70 and 100 ng/zone for (4) and (6) and 80 and 110 ng/zone for (7). The intermediate precision was below 1.5 % (n=3). Recovery was in the range of 98-100 %.

J. Planar Chromatogr. 31, 429-436 (2018). HPTLC of _x000D_caffeic acid (1), ferulic acid (2), β-sitosterol (3), and lupeol (4) on silica gel with toluene – ethyl acetate – formic acid 85:15:1. Quantitative determination by absorbance measurement at 366 nm for (1) and (2) and 580 nm for (3) and (4). The hRF values for (1) to (4) were 14, 29, 48 and 63, respectively. Linearity ranged between 100-600 ng/zone for (1) and (2) and 200-700 ng/zone for (3) and (4). LOD and LOQ were 49 and 149 ng/zone for (1), 93 and 282 ng/zone for (2), 194 and 589 ng/zone for (3) and 36 and 109 ng/zone for (4), respectively. The intermediate precision was <2 % (n=6). Average recovery was 99.6 % for (1), 99.9 % for (2), 99.2 % for (3) and 99.5 % for (4).

J. Agric. Food Chem. 34, 105-108 (1986). TLC analysis of steroids on silica with chloroform - acetone 95:5, preparative purification of ergosterol peroxide on a centrifugally accelerated radial thin-layer chromatograph with hexane - ethyl acetate 7:3, at a flow rate of 4 ml/min.

Phytochemistry 28, 2931-2935 (1989). TLC of 14C labeled substances: separation of cholesteryl or hexadecanyl esters from cholesterol or hexadecanol on silica with hexane - acetone 49:1 or hexane - chloroform 3:2. Localization of substances with Rhodamin 6G. Autoradiography.

(Hungarian). Magyar Kémiai Folyóirat 99, 271-274 (1993). TLC of 3ß-hydroxy-5a-cholest-8(14)-en-15-one on silica with hexane - ethyl acetate 9:1, dichloromethane - acetone 97:3, or benzene - methanol 98:2. Detection under UV 254 and 366 nm.