J. Planar Chromatogr. 24, 394-399 (2011). TLC of leave extracts and six flavonoids as markers (vitexin, isovitexin, orientin, isoorientin, quercetin, and tricin) on silica gel, prewashed with methanol and methylene chloride, with methanol - ethyl acetate - acetone - methylene chloride in different ratios using automated multiple development. The developed plate was dried in air for 2 h and sprayed with 1 % aluminum trichloride in ethanol. Then the plate was left for 2 h for derivatization in a glass drying chamber. Quantitative determination by densitometry at 366 nm. The hRf values of the six marker flavonoids were 22, 31, 38, 45, 57, and 88, respectively. Linearity was between 175 and 1750 ng/band. Instrument precision (n = 10) was between 0.2-0.9 %. The repeatability for standards and samples (n = 9), was 0.7 and 0.5, 0.8 and 0.5, 0.8 and 0.5, 0.8 and 0.4, 1.3 and 0.7, 1.1 and 0.3 % for isoorientin, orientin, isovitexin, vitexin, quercetin, and tricin, respectively. The limits of detection were 35, 40, 35, 50, 80, and 20 ng/zone for isoorientin, orientin, isovitexin, vitexin, quercetin, and tricin, respectively. The intra-day and inter-day precision was between 0.1-2.9 % and 0.3-2.4 % for all six marker flavonoids.

Planta Med. 76, 474-480 (2010). HPTLC of camptothecin and plant material extracts (roots, stems, leaves,and fruits) on silica gel with chloroform - ethyl acetate - methanol 9:10:1 in a twin trough chamber at 25 +/- 2°C and 40 % relative humidity. Quantitative determination by densitometry at 360 nm. Linearity was between 80 and 480 ng/zone with a correlation coefficient of 0.998 +/- 0.020. Instrumental precision (%RSD) was 0.5 %. Repeatability (%RSD) of sample and standard were 1.1 and 1.0 %. The LOD and LOQ were found to be 40 and 80 ng/zone, respectively. The accuracy of the method was proven by the average percentage recovery of 99.1 %.

Planta Med. 75, 12-17 (2009). HPTLC of swertiamarin and the ethyl acetate extract of Enicostemma axillare on silica gel with ethyl acetate - butanol 1:1 in a twin trough chamber. Quantitative determination by densitometric absorbance measurement at 254 nm.

J. Planar Chromatogr. 23, 315-319 (2010). HPTLC of polyphenols (extracted from Quercus robur) and quercetin, chlorogenic acid, gallic acid, and rutin as standards on silica gel with ethyl acetate - water - formic acid 87:3:10 in an unsaturated twin-trough chamber. Detection by spraying with 1 % 2-aminoethyl diphenylborinate (natural products reagent) followed by 2 % polyethylene glycol 4000 solution as well as by spraying with 2 % phosphomolybdic acid reagent followed by heating at 120 °C for 5 min. Evaluation by densitometry in absorption mode at 700 nm.

J. Planar Chromatogr. 24, 534-538 (2011). HPTLC of clarithromycin in plasma on silica gel (prewashed with methanol) with ethyl acetate - methanol - 15 % ammonium acetate (pH 10.6) 7:2:1 in a twin-trough chamber with saturation for 15 min. Detection by dipping into xanthydrol solution (10 % in methanol). Quantitative determination by densitometry in absorbance mode at 506 nm. The hRf was 62. The method was linear over the range of 0.1-3.0 µg/mL (r2 = 0.9974). The recovery (by standard addition) was over 85 %. The intra-day and inter-day precision (%RSD) of the assay was in the range of 0.8-4.6 %. The recovery was above 95 %.

J. Planar Chromatogr. 24, 503-506 (2011). HPTLC of oleanolic acid in extracts of dried roots on silica gel with toluene - ethyl acetate - glacial acetic acid 70:30:1 in a saturated twin-trough chamber. Detection by spraying with anisaldehyde-sulfuric acid reagent and heating in an oven at 110 °C for 5 min. Quantification was performed by immediate densitometric absorbance measurement at 529 nm. The average recovery was 98.9 %. LOD and LOQ were 10 and 30 ng/zone, respectively. The hRf value was 58. Linearity was between 100 and 1000 ng/zone. Precision (%RSD) was 1.4 %.

J. Liq. Chromatogr. Relat. Technol. 34, 1664-1675 (2011). HPTLC of pramipexole in pharmaceutical formulations on silica gel with ethyl acetate - toluene - methanol 16:3:1 + 1 drop ammonia. Quantitative determination by absorbance measurement at 263 nm. The hRf value of pramipexole was 32. Precision was below 2 %. Linearity was 200-2000 ng/zone. LOD and LOQ were found to be 30 and 200 ng/zone. The intermediate/inter-day/intra-day precision (n = 6) was 0.4 %. Recovery (by standard addition) was in the range of 98.5-99.1 %.

J. Planar Chromatogr. 25, 509-515 (2012). HPTLC of textile dyes Lanasyn Blue F-L 150 (1), Lanasyn Dark Brown M-GLN (2), Lanasyn Red M-GA (3), Nylosan Dark Brown S-MBL (4), and Nylosan Red N-2RBL (5) on RP-18 with n-butanol - ethyl acetate - 5 % ammonium hydroxide 4:4:1. Quantitative determination by absorbance measurement at 550 nm. Linearity was in the range of 20-60 ng/band. Limits of detection for (1) to (5) were 7, 6, 3, 5 and 1 ng/band, respectively.