J Young Pharm 1(5), 82-85 (2010). HPTLC of ascorbic acid in different varieties of amla fruit (collected from different geographical regions) on silica gel with ethanol - acetic acid 19:1. The hRf value of ascorbic acid was 76. Densitometric evaluation at 254 nm. The method was linear in the range of 1-5 µg/band. Bigger fruits were found to contain higher concentrations of ascorbic acid. The reported method was applied for estimation of ascorbic acid in crude drug as well as in herbal and pharmaceutical dosage form with reproducible results.

Asian Journal of Chemistry 23(1), 385-387 (2011). HPTLC on silica gel with chloroform - ethyl acetate containing 1 % acetic acid. Two well resolved zones with hRf values of 33 and 55 were obtained by illumination at 254 nm. The zones were labelled as substance I and II and used for standardization of the oil. Densitometric evaluation at 265 nm. The linearity range for both substances was 4-100 µg/band. The recovery was in the range of 97.4-98.7 %. Several commercially available tablets and capsules were analyzed for the content of Neem oil using substances I and II as marker (in the absence of chemical markers).

Phytochem. Anal. 21, 463-469 (2010). HPTLC of pyrocatechol in the barks of different species and clones from the genus Salix on diol phase by mutiple gradient development with chloroform - hexane 7:3 - ethyl acetate - formic acid in the following gradients: (I) 18:2:0.01, (II) 17:3, and (III) 16:4. Detection by spraying with thymol reagent. Quantitative determination by absorbance measurement at 254 nm.The hRF of pyrocatechol was 25. Detection and quantification limits were 30 and 100 µg/mL, respectively. The intra-day and inter-day precisions had a %RSD lower than 2.5 %. Recovery (by standard addition) was 96.3 %. The correlation coefficient of pyrocatechol concentrations determined by HPTLC and HPLC was 0.9932.

Journal of Pharmacy Research 3(5), 1107-1109 (2010). HPTLC of mangiferin in Salacia chinesis (Hippocrateaceae) on silica gel with ethyl acetate - methanol 2:3 at 25 °C with chamber saturation for 30 min. Densitometric evaluation at 254 nm. Derivatization by spraying with acetic anhydride-sulfuric acid-ethanol reagent, followed by heating at 110 °C for 2 min. The method was linear in the range of 10-200 ng/band. The plant was found to contain 1.54 % of mangiferin.

International J. Pharm. & Tech 2(2), 285-292 (2010). TLC of gallic acid in acetone extracts of bark powder of Acacia nilotica on silica gel with toluene – ethyl acetate – formic acid 15:10:2. The hRf value of gallic acid was 36. Quantitative determination by absorbance measurement at 280 nm. The method was linear in the range of 100-350 ng/band with recovery of 97.5 %.

J.of Jiangxi Univ. of TCM 22 (5), 55-57 (2010). TLC of Shujinhuoxue pills: 1) for Angelica sinensis, on silica gel with cyclohexane – ethyl acetate 12:1, detection under UV 365 nm; 2) for Rheum officinale, on silica gel with petroleum ether (30-60 ºC) – ethyl formate – formic acid 15:5:1, detection by exposure to ammonia vapors; 3) for Radix Rehmanniae praeparata, on silica gel with petroleum ether (60-90 ºC) – ethyl acetate 1:1, detection under UV 254 nm; 4) for Gardenia jasminoides, on silica gel with ethyl acetate – acetone – formic acid – water 5:5:1:1, detection by spraying with 10 % sulfuric acid in ethanol and heating at 110 ºC until the zones were visualized; 5) for Lignum Sappan, on polyamide phase with 36 % acetic acid, detection by spraying with 5 % AlCl3 in ethanol and heating mildly until the spots were visualized.

International Journal of PharmTech Research 3(2), 986-999 (2011). TLC of methanolic extracts of Haritaki and gallic acid and rutin as markers on silica gel with toluene - ethyl acetate - formic acid 3:6:1 for gallic acid and chloroform - ethyl acetate - methanol - formic acid 7:10:1:2 for rutin. Quantitative determination by densitometry in absorbance mode at 280 nm for gallic acid and 254 nm for rutin. The method was linear in the range of 100-500 ng/band for gallic acid and 1000-5000 ng/band for rutin. The recovery was 99.1 % for gallic acid and 97.9 % for rutin. The LOD and LOQ of gallic acid was 71 and 213 ng/zone and of rutin 63 and 189 ng/zone.

PHCOG J. 2(11), 381-385 (2010). TLC of Tylophora indica leaves, extracted with petroleum ether, chloroform and methanol, on silica gel with 1) n-hexane - ethyl acetate 2:3 for the petroleum ether extract, 2) chloroform - ethyl acetate - methanol 18:1:1 for the chloroform extract, and 3) chloroform - toluene - ethyl acetate 18:1:1 for the methanolic extract. Evaluation under UV 254 nm and 366 nm. 12 prominent bands were observed in all chromatographic fingerprints. The method is suitable for identification and authentication of the plant material.