J. Agric. Food Chem. 58, 4939-4944 (2010). HPTLC of azadirachtin (1) and salannin (2) in the seeds of Azadirachta indica on silica gel with hexane - ethyl acetate1:3. Quantitative determination by absorbance measurement at 220 nm. The hRf values of (1) and (2) were 18 and 30, respectively. Linearity was between 50 and 200 ppm for both (1) and (2). Recovery was 99.9 % for (1) and 99.3 % for (2). The intermediate precision was 88.5 % and 87.5 % for (1) and (2), respectively (n=3). The HPTLC and HPLC methods gave comparable results.

Journal of Pharmacy Research 3(5), 1144-1145 (2010). The plant material (Nicotiana tabacum leaves) was extracted with non-polar and polar solvents. The resulting extracts were subjected to screening for different phyto-constituents (such as terpenes, saponins, flavonoids, alkaloids, and steroids) on silica gel using n-hexane - ethyl acetate 5:1 for fingerprint profiling. Detection under UV 254 nm. For derivatization the plate was sprayed with anisaldehyde-sulfuric acid reagent followed by densitometric evaluation at 550 nm. It was observed that fingerprint profiling after derivatization was more suitable than under UV before derivatization. Methanolic extracts of the plant yielded a superior profile.

J. Pharm. Biomed. Anal. 54, 422-425 (2011). HPTLC of aloin in several aloe dried extracts and related commercial formulations on silica gel with ethyl formate – methanol – water 200:29:20. Evaluation under 254 nm. Detection by immersion in 10 % H3BO3 in methanol, followed by heating at 110 °C for 10 min. Quantitative determination by fluorescence measurement at 365/K540 nm.

International J. Research in Ayurveda & Pharmacy 1(1), 131-134 (2010). Dried leaves of Calendula officinalis were extracted with petroleum ether, chloroform, methanol and water, the solvents were removed and the extracts were subjected to phytochemical analysis for amino acids, essential oils, triterpens, alkaloids, saponins, sterols, and fatty acids. TLC on silica gel with n-hexan – acetic acid – water 12:3:5, detection by spraying with ninhydrin solution, followed by heating at 105 °C revealed violet bands which indicated the presence of amino acids. For essential oils TLC on silica gel with dichloromethane – chloroform – ethyl acetate – n-propanol 94:90:4:5, followed by spraying with vanillin-sulfuric acid reagent and heating at 105 °C for 2 min. Pink brown coloured zones indicated the presence of essential oils. For triterpenoids TLC on silica gel with n-butanol – 2M ammonia 1:1 , detection by spraying with antimony trichloride solution. Purple coloured zones indicated the presence of triterpenoids. For alkaloids TLC on silica gel with chloroform – methanol 1:1, detection by alkaloids-reagent. For saponins TLC on silica gel with chloroform – methanol 12:1, detection by spraying with vanillin-sulfuric acid reagent. For sterols TLC on silica gel with chloroform – methanol 3:4, detection by anisaldehyde reagent. For fatty acids TLC on silica gel with n-hexane – ethyl acetate 19:1, detection by KMnO4 reagent.

Planta Med. 74, 1397-1402 (2008). Analytical and preparative TLC of three steroidal saponins (25R)-spirost-5-ene-3ß, 17alpha-diol (pennogenin), 3-O-{O-alpha-L-rhamnopyranosyl-(1-2)-O-[O-ß-xylopyranosyl-(1-5)-alpha-L-arabinofuranosyl-(1-4)]-ß-D-glucopyranoside} on silica gel with dichloromethane - methanol - water 80:19:1 or 70:29:1. Detection by spraying with phosphomolybdic acid. Additional detection by antifungal bioassays.

J. Planar Chromatogr. 24, 316-319 (2011). HPTLC of Palmarosa oil extracts in toluene and geraniol on silica gel with toluene - ethyl acetate 37:3 in a twin-trough chamber saturated for 30 min at 25 +/- 2 °C. Detection by spraying with 3 % vanillin in ethanol - sulfuric acid 49:1 followed by heating at 100 °C for 5 min. Quantitative determination by densitometry in absorption mode at 400 nm. The instrumental precision and the repeatability (n = 6), was 0.3 and 3.2 %, respectively. LOD and LOQ was 1.4 and 2.8 µg/mL, respectively. The intra-day recovery was 99.8 % and the inter-day recovery 99.4 %. The hRf value for geraniol was 36.

J. Planar Chromatogr. 24, 253-256 (2011). HPTLC of yohimbine on silica gel, prewashed with methanol, with toluene - ethyl acetate - diethyl amine 7:2:1 in a twin trough chamber saturated with mobile phase for 10 min at 25 +/- 2 °C. Quantitative determination by densitometry in absorbance mode at 285 nm. Linearity was between 400 and 1200 ng/band. The hRf value was 39. The repeatability as system precision and method precision (n = 6) was 0.9 and 0.8 % CV. The limit of detection and quantification was 80 ng and 260 ng. The instrument precision (n = 6), intra-day and inter-day precision (n = 3, %RSD) were 0.2, 0.1, and 0.1 %, respectively.

J. Planar Chromatogr. 24, 125-129 (2011). HPTLC of plant extracts and oxyresveratrol on silica gel, prewashed with methanol, with hexane - ethyl acetate - chloroform - methanol 15:10:17:8 in a twin-trough chamber lined with filter paper and saturated for 20 min. Quantitative determination by densitometry at 327 nm. LOD and LOQ were 50 and 200 ng/band, respectively. The hRf value of oxyresveratrol was 31. Intra-day and inter-day variation (%RSD) were consistently below 5.0 %. Within-day precisions for the replicate analysis (n = 3) were in the range of 1.1-4.1 %. Day-to-day replicates (n = 9) were between 2.1-2.8 %.