J. Planar Chromatogr. 22, 385-387 (2009). Ultrathin-layer chromatography of quercetin, rutin, and quercetin-3-O-glucoside on monolithic silica gel (size 30 mm x 18 mm) with binary and tertiary mobile phases in a cylindrical glass chamber previously saturated for 1 min. The migration distance was 20 mm and development time was 2 min. The investigated mobile phases were ethyl acetate - n-hexane 1:4 and 3:7, tetrahydrofurane - hexane 2:3 and 3:2, tetrahydrofurane - methanol - hexane 3:3:4, and hexane - acetone - methyl ethyl ketone 3:3:4. The best separation was achieved with acetone - methyl ethyl ketone - hexane 3:4:3. Densitometric evaluation at 366 nm.

J. Planar Chromatogr. 22, 283-286 (2009). HPTLC of withaferin and extracts of the powdered root on silica gel, prewashed with methanol, with toluene - ethyl acetate - acetone 2:3:3 in a twin trough chamber saturated with mobile phase for 30 min. Detection by spraying with anisaldehyde reagent followed by heating for 15 min at 105 °C; characteristic orange fluorescence was observed for whithaferin. Quantitative determination by absorbance measurement at 214 nm. The limit of detection and quantification for withaferin A was 258 and 782 ng/zone, respectively.

60th Indian Pharmaceutical Congress PA-223 (2008). HPTLC of curcumin, demethoxycurcumin and bis-demethoxycurcumin on silica gel with chloroform - methanol 19:1. The hRf values were 25, 38, and 61 for bis-demethoxycurcumin, demethoxycurcumin, and curcumin respectively. Quantitative determination by absorbance measurement at 420 nm. The method was linear in the range of 50-400 ng/spot (curcumin), 10-150 ng/spot (demethoxycurcumin), and 5-40 ng/spot (bis-demethoxycurcumin). Recovery was in the range of 99.2-100.5 % for all three compounds.

J. Chinese Trad. & Herb. Drugs 40 (6), 900-903 (2009). TLC of the TCM drug extracts on silica gel with 1) ethyl acetate - formic acid - glacial acetic acid - water 15:1:1:2; 2) petroleum ether (30-60 °C) - ethyl acetate - formic acid 15:5:1; 3) chloroform - ethyl acetate - methanol - water 31:81:25:2. Detection 1) by spraying with 10 % sulfuric acid in ethanol followed by heating at 105 °C until coloration; 2) under UV 254 nm.

Abstract No. C-231, 61st IPC (2009). An HPTLC method is reported for determination of 3-OH-androstane-(16,17-C) (6-methyl-2-1-hydroxy-isopropene-1-yl)-4,5,6 H-pyran, a phyto constituent of Eugenia jambolana. The compound was isolated by ethanolic extraction, identified by melting point, IR, and NMR, and used as marker. HPTLC on silica gel with toluene - ethyl acetate 17:3. Densitometric evaluation at 366 nm. The method was linear in the range of 1000-5000 ng/band. It can be used for routine quality control of Eugenia jambolana seeds and herbal formulation.

CBS 103, 10-12 (2009). HPTLC of plant extracts and standards chlorogenic acid, hyperoside, rutin, quercetin and kaempferol (0.1 % in methanol) on silica gel in a twin-trough chamber with ethyl acetate - formic acid - glacial acetic acid - water 100:11:11:27. Detection by spraying with various detection reagents: 1) natural products reagent, evaluation under UV 366 nm, 2) anisaldehyde reagent, evaluation under white light, 3) diphenyl-2-picrylhydrazyl reagent (DPPH radical), evaluation under white light, 4) rhodamine B reagent, evaluation under UV 366 nm, 5) Dragendorff reagent, evaluation under white light.

Journal of Pharmacy Research 2(5), 789-791 (2009). TLC of harmaline in methanolic leaf extracts of Passiflora foetida on silica gel with chloroform - acetone - diethylamine 5:4:1. The hRf value of harmaline was 76. Densitometric quantification at 351 nm. The plant was found to contain 0.75 % w/w of harmaline. The method was linear in the range of 1-10 µg/band.

Acta Chromatographica 21(2), 203-215 (2009). HPTLC of commercial products containing Heterotheca inuloides, Citrus aurantium, Peumus boldus, Equisetum arvense, Eucalyptus globulus, Ginkgo biloba, Mentha piperita, Aloe vera, Salvia officinalis , and Cassia senna on silica gel with different mobile phases. The mobile phase for aloin, boldine, chlorogenic acid, rutin, kaempferol, caffeic acid, and quercetin was ethyl acetate – methanol – water 100:17:13; for menthol, cineole, menthone, alpha- and beta-thujone, geraniol, linalyl acetate and linalool it was toluene – ethyl acetate 93:7; for ginkolide B toluene – ethyl acetate – acetone – methanol 50:25:25:3; and for sennoside B ethyl acetate – formic acid – acetic acid – water 100:11:11:27. Detection with natural products reagent, anisaldehyde reagent or Liebermann-Burchard reagent. We found that in only 20 % of the 40 commercial products analysed the chromatographic characteristics of the respective plants matched those of the specific respective marker compounds. This highlights a problem arising from the lack of regulation of these products, and emphasizes the need to develop simple and reliable analytical methods like TLC methods that can be performed in any laboratory for the purpose of quality control of dietary supplements or commercial herbal products sold in Mexico.