J. of Chromatogr. Sci. 49, 560-567 (2011). Evaluation of the fingerprinting efficiency of a novel two-dimensional analytical system composed of RP-TLC and RP-LC-MS. The efficiency of the system was compared with that of the one-dimensional system RP-TLC with MS detection. The test samples were phenolic acid extracts from Salvia lavandulifolia. Both systems can be applied to the fingerprint analysis of herbal extracts, but the two-dimensional system based on RP-TLC and RP-LC-MS can provide more abundant information.

leaves and its geographical variation using HPTLC fingerprint. Trends in Natural Product Research, NRP-2011 abstract No. SNP-NRP-11/069. TLC of ferulic acid in ethanolic extracts of Ricinus communis leaves on silica gel with chloroform - methanol 19:1. Quantitative determination by densitometry at 366 nm. The method was linear in the range of 300-900 ng/band. LOD and LOQ were 4 and 11 ng/zone, respectively. The plant collected from different geographic locations showed variations in the amount of ferulic acid. The content of ferulic acid was 2.87 µg/g in leaves collected from Delhi, which was higher than those from Guwahati and Jhansi.

Journal of Pharmacy Research 4(4), 1197-1198 (2011) Vitamin C contents were estimated in fruit and fruit pulp. HPTLC of vitamin C from methanolic extracts of Pithecellobium dulce pods on silica gel with ethanol - water 2:1. Densitometric quantification at 254 nm. The method was linear in the range of 100-600 ng/band. The method could be employed for quality control of formulation containing the plant as one of the ingredient.

J. Planar Chromatogr. 24, 306-311 (2011). HPTLC of ethanolic leaf extracts of A. squamosa, with rutin and isoquercitrin as standards, on silica gel (prewashed with methanol) with ethyl acetate - formic acid - glacial acetic acid - ethyl methyl ketone - water 50:7:3:30:10 with chamber saturation for 30 min at room temperature (25 +/- 2°C) and a relative humidity of 50 +/- 5 %. Quantitative determination by densitometry at 366 nm. Linearity was between 200-1600 ng/band for both rutin and isoquercitrin. The robustness of the method (%RSD) was 1.9-2.9 % for rutin and 1.5-2.3 % for isoquercitrin, respectively. The instrumental precision (%RSD) was 0.9 and 0.3 % for rutin and isoquercitrin, respectively. The intra-day and inter-day precision (%RSD) was less than 3 % in all cases. LOD and LOQ was 75 and 100 ng/band for rutin and 40 and 80 ng/band for isoquercitrin, respectively. The hRf value was 32 for rutin and 58 for isoquercitrin. Recovery (by standard addition) was found to be 96-107 %.

Planta Med. 77, 548 (2011). HPTLC of glabridin (4-[(3R)-8,8-dimethyl-3,4-dihydro-2H-pyrano[6,5-f]chromen-3-yl]benzene-1,3-diol) on silica gel with toluene - dichloromethane - ethyl acetate 1:1:1. Detection under UV light at 286 nm.

J. Planar Chromatogr. 24, 513-519 (2011). TLC of nabumetone (4-(6-methoxy-2-naphthyl)butan-2-one) on silica gel with n-hexane - chloroform - glacial acetic acid 4:1:1 with chamber saturation for 15 min. Quantitative determination by densitometry in absorbance mode at 270 and 330 nm. LOD and LOQ ranged from 0.23-1.00 µg/band. The recovery was between 98.9-101.7 % (at measurement wavelength 270 nm) and 99.6-101.7 % (at measurement wavelength 330 nm). The precision (%RSD) was below 2 % for all concentration levels. Linearity was between 0.3-3.5 µg/band. The hRf value was 72.

J. Planar Chromatogr. 25, 314-319 (2012). HPTLC of 4-odemethylpodophyllotoxin (1), podophyllotoxin (2), kaempferol (3), podophyllotoxone (4), and deoxypodophyllotoxin (5) in the rhizomes of Podophyllum hexandrum on silica gel with toluene - ethyl acetate 2:1 + 1 drop glacial acetic acid. Quantitative determination by absorbance measurement at 254 nm. Linearity was in the range of 1-8 µg/band for (1), (2) and (4) and 2-10 µg/band for (3) and (5). The intermediate/inter-day/intra-day precision was below 2 %. Average recovery for all (1) to (4) were between 96.4 and 101.8 %.

J. Liq. Chromatogr. Relat. Technol. 35, 484-498 (2012). HPTLC of vitamin K homologues including phylloquinone (1), menaquinone-4 (2), and menaquinone-7 (3) on silica gel with methanol - ethanol - isopropanol - water 15:1:1:3. Quantitative determination by absorbance measurement at 254 nm. The hRf values of compounds (1) to (3) were 56, 43 and 23, respectively. Linearity was in the range of 1-200 ng/band. Limits of detection and quantification were in the range of 0.2-0.9 and 0.7-2.5 ng/band, respectively. The intermediate/inter-day/intra-day precisions for (1) to (3) were in the range of 0.5-1.3 % (n=5). Recoveries were ranged from 95.3 to 100.8 %.