J. Planar Chromatogr. 31, 235-242 (2018). HPTLC of lormetazepam on silica gel with acetonitrile – water 3:2. Quantitative determination by absorbance measurement at 241 nm. The hRf value for lormetazepam was 44. Linearity was in the range of 1.0-7.5 μg/zone. The intermediate precision was below 4 % (n=3). The LOD and LOQ were 0.26 and 0.77 μg, respectively. Average recovery was 100.9 %. Comparable results were obtained with a validated HPLC method.

methanolic fraction. J. Planar Chromatogr. 31, 327-331 (2018). HPTLC of caffeic acid (1), vanillic acid (2), and syringic acid (3) in O. corniculata L. methanolic fraction on silica gel with toluene ‒ ethyl acetate ‒ formic acid 7:3:1. Quantitative determination by absorbance measurement at 300 nm. The hRF values for (1) to (3) were 36, 44 and 54, respectively. Linearity ranged between 100-700 ng/zone. LOD and LOQ were 40 and 100 ng /zone, respectively. The intermediate precision was <2 % (n=3). Recovery was between 97.1 and 99.6 %.

J. Chromatogr. A 1530, 197-203 (2017). Evaluation of the phenolic and stigmasterol content and comparison of the antioxidant and antidiabetic activities by HPTLC combined with DPPH* free radical method and α-amylase assay towards ethanol and ethyl acetate extracts of 10 marine macroalgae species (3 chlorophyta, 4 phaeophyta and 3 rhodophyta). HPTLC on silica gel with n-hexane – ethyl acetate – acetic acid 20:9:1 over 80 mm. Detection either by dipping into 0.4 % DPPH* solution followed by storing in the dark for 30 min before evaluation, or by dipping into anisaldehyde – sulfuric acid reagent or neutralized ferric chloride solution (prepared by adding dilute sodium hydroxide to freshly prepared 2 % ferric chloride in methanol until precipitation occurs, followed by filtering), both followed by heating at 100 °C for 10 min. Quantitative evaluation by absorbance measurement at 470 nm for detection of α-amylase inhibition and at 550 nm for stigmasterol. The results showed higher antioxidant activity in the ethyl acetate extracts than in ethanol extracts, and higher amounts of fucoxanthin, stigmasterol and α-amylase inhibitory activities in ethyl acetate extracts. The results proved the relation of higher α-amylase inhibition in ethyl acetate extracts due to the presence of triterpenes and sterols, and no contribution of fucoxanthin to it.

J. Chromatogr. A 1572, 152-161 (2018). Description of a novel application of HPTLC for separation and quantification of eight food colors (amaranth, allura red, erythrosine, fast green, indigo carmine, quinoline yellow, sunset yellow and tartrazine) and four intense sweeteners (acesulfame, aspartame, saccharin and neohesperidin) on silica gel with acetonitrile – water - ethyl acetate - 10 % aqueous ammonia 9:1:1:1. Quantitative determination by densitometry at 210, 295, 450 and 550 nm. The LOD and LOQ ranged from 0.2 to 10 ng/zone and from 1 to 30 ng/zone, respectively. The correlation coefficient (r2) values for the calibration curves were ≥ 0.9973 for all the additives. The recovery of different additives obtained from food products, beverages and pharmaceuticals ranged from 96.6 to 106.7 %.

II. Eleutherococcus senticosus maxim, panax ginseng Meyer and picrorrhiza kurroa Royle. J. Chromatogr. 312, 497-503 (1984). HPTLC of the title compound on silica with 1,2-dichloroethane - ethanol -methanol -water 65:22:22:7. Detection with a mixture (1:1) of 1 % vanillin in ethanol and 5 % sulfuric acid in ethanol. Densitometry at 530 nm after color stabilization (5 min.). The same method gave excellent results for the analysis of crude ginseng extracts. Also HPTLC of picrorrhiza kurroa extracts with dichloromethane-methanol - water 40:10:1. Detection at 268 and 285 nm. Precise and accurate HPTLC-densitometry method for the standardization of plant drugs.

V. Danube Symposium on Chromatography, Yalta, November 11-16, 1985. TLC on silica, impregnated with 5 % paraffin oil in hexane, developed with methanol - water with different organic phase ratio in the mobile phase.

Fresenius Z. Anal. Chem. 322, 513-514 (1985). Proof of enantiomeric purity by TLC of D- and L- (3, 4-dihydroxyphenylalanine) on MN-chiral plates with methanol -water - acetonitrile 5:5:3. Spots are visualized using 0.1 % ninhydrin reagent.

J. Liquid Chrom. 9, 3461-3457 (1986). Isolation of dexamethasone sodium phosphate and betamethasone sodium phosphate after alkaline phosphatase reaction. TLC on silica with chloroform - methanol - water 180:15:1 or dichloromethane - ether - methanol -water 77:15:8:1; location under short wave UV. Quantification after extraction with ethanol by absorbance at 240 nm. Average recovery 100.56 resp. 100.46 %. Assay of unesterified steroids and identification of preservatives (e.g. methyl or propyl parabenzoates, phenol, benzylalcohol) may be carried out by the same method.