J. Planar Chromatogr. 19, 449-453 (2006). HPTLC of caffeic, p-coumaric, and ferulic acid on silica gel with dichloromethane - acetonitrile - 90 % formic acid 95:5:1. Quantitative determination by absorbance measurement at 320 nm. The method is precise and accurate.

J. Sep. Sci. 27, 129-131 (2004). HPTLC of betulin in the bark of Grewia tiliaefolia Vahl. on silica gel with toluene – ethyl acetate 9:1. Quantitative determination by absorbance measurement. Linearity of determination of betulin is between 1000 and 1800 ng and its average percentage recovery is 96.09 - 98.87 %.

Phytochem. Anal. 17, 164-166 (2006). HPTLC of gymnemagenin on silica gel with chloroform - methanol 9:1. Quantitative determination by absorbance measurement at 290 nm. Linearity of the determination of gymnemagenin was observed in the range of 4 - 10 µg. The average percentage recovery from an extract was 99.1 %, the content of leaves was 1.61 % (dry weight).

J. Planar Chromatogr. 19, 278-281 (2006). Discussion of the deviation from the strict vertical of the migration tracks of chiral compounds during TLC on silica gel. Focus is put on possible crystalline asymmetry of the silica gel used in TLC. Description of an attempt to verify the hypothesis by means of circular dichroism spectroscopy. TLC of S-(+)-ibuprofen and S-(+)-naproxen on silica gel with acetonitrile - methanol - water 5:1:1 for S-(+)-ibuprofen and 10:2:3 for S-(+)-naproxen. Quantitative determination by absorbance measurement at 210 nm.

J. Liq. Chromatogr. & Relat. Technol. 29, 2753-2765 (2006). TLC of tadalafil [6R,12aR)-2,3,6,7,12a-hexahydro-2-methyl-6-[3,4-(methylenedioxy)phenyl]pyrazino-[1’,2’:1,6]pyrido[3,4-b]indole-1,4-dione] on silica gel with n-hexane - ethyl acetate - methanol 4:3:1. Quantitative determination by absorbance measurement at 285 nm.

Chromatographia 65 (3-4), 245-248 (2007). TLC of dimethyl phthalate, diethyl phthalate, dibutyl phthalate, di(2-ethylhexyl)phthalate (DEHP), benzyl butyl phthalate, diisodecyl phthalate, dimethyl adipate, diethyl adipate, di(2-ethylhexyl)adipate, triethyl citrate, tributyl citrate, tributyl acetyl citrate and n-butyl stearate on inorganic ion-exchanger stannic silicate with toluene - ethyl acetate 10:1 over 12 cm (25 min). Quantification of DEHP by densitometry at 280 nm. Limit of quantitation for DEHP was 0.50 µg/zone and limit of detection 0.05 µg/zone.

J. Sep. Sci. 30, 2786-2793 (2007). HPTLC of unsaponifiable constituents of rice bran oil on silica gel in two stage separation: First separation with benzene – chloroform 12:1 for sterols, oryzanols, and tocols. Quantitative determination by absorbance measurement at 206 nm for sterols (1), 325 nm for oryzanols (2), and 297 nm for tocols (3). Second separation with petroleum ether – diethyl ether 50:1 for steryl esters (4), wax (5), and squalene (6). Detection by dipping in 5 % methanolic sulphuric acid followed by heating at 110 °C for 1 hour. Quantitative determination by absorbance measurement at 439 nm. The hRf values were 12 for (1), 21 for (2), 39 for (3), 36 for (4), 46 for (5), and 74 for (6). Linearity was between 150 and 1200 ng/zone for the first separation and between 400 and 1200 ng/zone the second separation. The limits of detection and quantification were 6 and 20 ng/zone for (1), 1 and 4 ng/zone for (2), 11 and 38 ng/zone for (3), 22 and 73 ng/zone for (4), 19 and 65 ng/zone for (5), and 3 and 10 ng/zone for (6), respectively. Intra-assay precision was between 0.52 and 1.94 % and inter-assay precision was between 0.87 and 2.27 %. Recoveries ranged from 93.5 to 101.9 %.

J. Sep. Sci. 30, 3311-3315 (2007). HPTLC of lawsone in the leaves of Lawsonia alba on silica gel with chloroform – methanol 17:3. Quantitative determination by absorbance measurement at 334 nm. The hRf value of lawsone was 40 and selectivity regarding matrix was given. Linearity was between 100 and 1000 ng/zone. The precision was 1.72 % and recovery (by standard addition) was 98.8 %.