J. Planar Chromatogr. 28, 213-217 (2015). HPTLC of (1) chlorogenic acid, (2) caffeic acid, (3) faradiol and (4) rutin from Calendula officinalis plant extracts on silica gel previously activated at 50 °C in an oven for 30 min. Automated multiple development (gradient elution) with n-hexane, ethyl acetate containing 2 % acetic acid, and water as mobile phase. Detection by spraying with either 10 % sulfuric acid in methanol or 2-aminoethyl diphenylborinate solution followed by placing in oven at 50 °C for 30 min. (1), (2), (3), and (4) were used as markers to investigate and assess the quantitative errors observed. Accuracy of the sample applicator at different sample volumes, the use of a gradient mobile phase, and post-derivatization contribute to uncertainties of the HPTLC method and need to be carefully selected to minimize errors.

J. Ethnopharmacol. 182, 150-159 (2016). HPTLC of 3,5,7,3′,4′-pentahydroxy flavone in the leaves of Madhuca indica on silica gel with acetone – n-hexane 1:3. The hRF value for the active compound with potent antiulcer activity was 40.

J. Ethnopharmacol. 195, 324-333 (2017). HPTLC of quercetin (1), kaempferol (2), beta-sitosterol (3) and luteolin (4) in fresh flowers of Saraca asoca on silica gel with toluene – acetone – formic acid 10:4:1 for (1), cyclohexane – ethyl acetate – methanol – formic acid 12:9:1:1 for (2), toluene – methanol 8:1 for (3) and toluene – ethyl acetate – formic acid 15:15:4 for (4). Quantitative determination by absorbance measurement at 378 nm for (1), 365 nm for (2), 366 nm for (3) and 254 nm for (4). The hRF values for (1) to (4) were 29, 35, 42 and 45 respectively.

J. Planar Chromatogr. 31, 135-142 (2018). HPTLC of glycyrrhizin (1) and glabridin (2) in the roots, rhizomes and herbal formulations of Glycyrrhiza glabra on RP-18 with methanol – water 7:3. Quantitative determination by absorbance measurement at 256 nm for (1) and 233 nm for (2), respectively. The hRf values for (1) and (2) were 63 and 28, respectively. Linearity was in the range of 1000-7000 ng/zone for (1) and 100-700 ng/zone for (2). The intermediate precision was below 1.3 % (n=6). The LOD and LOQ for (1) and (2) were 8 and 15 ng/zone for (1) and 5 and 18 ng/mL for (2), respectively. Recovery was in the range of 98.9-99.6 % for (1) and 97.3-99.1 % for (2).

Pharmacogn. Mag. 14, 294-303 (2018). HPTLC of gallic acid (1), ascorbic acid (2), hesperidin (3), and quercetin (4) in the leaves of Rhododendron arboreum and Rhododendron campanulatum on silica gel with ethyl acetate – dichloromethane – glacial acetic acid – formic acid – methanol 10:10:1:1:2. Quantitative determination by absorbance measurement at 254 nm. The hRF values for (1) to (4) were 74, 31, 20 and 87, respectively.

Phytochemistry 24, 1587-1591 (1985). TLC of cucurbitacins on silica with chloroform - methanol 9:1. Detection with vanillin - phosphoric acid reagent. For the detection of alpha-ketolcucurbitacins, the plates were sprayed with a 1:1 mixture of triphenyltetrazolium chloride (4 % in ethanol) and NaOH 1 N. Flavonoid glycosides were separated on silica with ethyl acetate - formic acid - acetic acid - water 100:11:11:27. Detection with diphenylboryloxyethylamine reagent, followed by PEG 4000 (5 % in ethanol, UV 365 nm.

Biochemical Systematics and Ecology 15, 57-59 (1987). Two-dimensional TLC of quercetin and patuletin diglycosides on polyamide with 1) water - butanol - acetone - dioxane 70:15:10:5 and 2) benzene methanol - butanone - water 55:25:23:2. Visualization by spraying with a 0.1 % solution of beta-aminoethyl diphenylborate in 50 % methanol.

Biochemical Systematics and Ecology 16, 411-412 (1988). TLC of patuletin, jaceidin, betuletol, axillarin, spinacetin, 6-methoxykaempferol, hispidulin and santin on polyamide with toluene - petrol ether - ethyl acetate - methanol 60:30:10:5 or toluene - ethyl acetate - methanol 60:25:15. Detection under UV.