Chinese J. Mod. Drug Appl. 4(15), 16-17 (2010). TLC on silica gel 1) with n-butanol – glacial acetic acid – water 4:1:5 for Xanthium sibiricum Patr., detection by exposure to iodine vapors; 2) with trichloromethane – diethyl ether 5:1 for Flos magnoliae, detection by spraying with 10 % sulfuric acid in ethanol and heating at 90 °C until the zones were visualized; 3) with n-butanol – ethyl acetate 17:3 for herba Menthae, detection by spraying with vanillin reagent and heating at 105 °C until the zones were visible; 4) with petroleum ether (30-90 °C) – ethyl acetate 17:3 for Angelica dahurica (Fisch. ex Hoffm.) Benth. et Hook. f. ex Franch. et Sav., detection under UV 366 nm.

Planta Med. 75, 711-718 (2009). For many decades, planar chromatography has been used for the analysis of plants, in particular today in its most advanced form of HPTLC. The technique is e. g. used for the identification of medicinal plants and dietary supplements, and for the detection of adulteration and quantitative determination of marker substances. Reliable qualitative and quantitative results can be achieved based on suitable instrumentation and adequate methodological concepts. The manageability of the entire planar chromatographic process has improved. Integration of biological detection systems as well as hyphenation to mass spectroscopy has widened the applicability of planar chromatography as an important analytical technique. The introduction is followed by explanation of HPTLC, use of HPTLC in plant analysis, limitations, applications (identification, detection of adulteration and quantitation), and instrumentation (chromatogram development, documentation, detection and evaluation).

Tianjin J. of Trad. Chinese Med. & Pharm. 28 (2), 164-166 (2011). TLC of the extracts of the traditional Mongolian medicine on silica gel 1) for artificial cow-bezoar, with isooctane - ethyl acetate - glacial acetic acid 6:3:2, detection by spraying with 10 % sulfuric acid in ethanol and heating at 105 °C until the zones were detected under UV 365 nm, identification by comparison with the fingerprint of the individual drug components and cholic acid as reference; 2) for Coptidis rhizoma, with benzene - ethyl acetate - isopropanol - methanol - water 20:10:5:5:1, detection under UV 365 nm after exposure to ammonia vapour, identification by comparison of the fingerprint with the individual drug components and berberine hydrochloride as reference; 3) for light yellow Sophora root, with ethyl acetate - propanone - benzene - ammonia water 20:15:10:1, detection by spraying with 5 % potassium iodobismuthate solution, identification by comparison of the fingerprint with the individual drug components and with matrine as reference.

J. Planar Chromatogr. 24, 66-71 (2011). HPTLC of extracts of Stresroak premix and gallic acid (1), mangiferin (2), and withanolide A (3) as standards on silica gel with A) ethyl acetate - formic acid - acetic acid - water 100:11:11:27, for (1) and (2), and B) chloroform - methanol 9:1 for (2) in a twin trough chamber. Quantitative determination by absorbance measurement at 280 nm for (1), 330 nm for (2), and 225 nm for (3). The hRf values of (1), (2) and (3) were 76, 29, and 48, respectively. The average recoveries were 100.4 % (1), 99.3 % (2) and 98.0 % (3). The linear concentration range was 50-150 ppm for (1), and 40-100 ppm for (2) and (3). The LOD, defined as the amount of compound required to produce a signal at least three times the noise level, for gallic acid, mangiferin, and withanolide A was 80, 110, and 200 ng for (1), (2), and (3), respectively. The LOQ was 20, 27, and 38 µg, respectively.

Planta Med. 77, 362-367 (2011). Analytical and preparative TLC of 19 sesquiterpenoids (e.g., ivalin, 6ß-hydroxytomentosin, 4-epipulchellin 2-O-acetate, and bigelovin) on silica gel with chloroform - ethyl acetate 8:1 and chloroform - methanol 15:1. Detection under UV 254 nm and by spraying with 98 % sulfuric acid - ethanol 1:19, followed by heating.

J. Ethnopharmacol. 137, 341-344 (2011). HPTLC of quercetin (1) and kaempferol (2) in the leaves of Argyreia speciosa on silica gel with toluene - ethyl acetate 93:7. Quantitative determination by absorbance measurement at 254 nm. The hRf values of (1) and (2) were 32 and 75, respectively and their amount was found to be 0.6 % and 0.2 %, respectively.

J. Liq. Chromatogr. Relat. Technol. 34, 2664-2673 (2011). HPTLC of curcumin (1) and gallic acid (2) in pharmaceutical formulations containing Curcuma longa Linn and Emblica officinalis extracts, on silica gel with chloroform - ethyl acetate 5:4 + 1 drop formic acid. Quantitative determination by absorbance measurement at 254 nm. The hRf values of (1) and (2) were 55 and 26, respectively. Linearity was between 30-700 ng/zone for (1) and 100-700 ng/zone for (2). LOD and LOQ were 100 and 300 ng/zone for (1), and 33 and 100 ng/zone for (2), respectively. The intermediate/inter-day/intra-day precision (n = 6) was 0.3 % for (1), and 0.1 % for (2). Recoveries (by standard addition) were 98.2-104.0 % for (1) and 97.8-101.5 % for (2).

J. of China Pharm. 21 (10), 31-32 (2012). Chuanyushaoshang cream is a herbal TCM preparation for external application for protecting wounds, promoting wound healing, antibiosis, invigorating the circulation of blood, and relieving pain. For quality control, TLC of emodin, one of the key active constituents in the extracts of the preparations, on silica gel with petroleum ether (60-90 ºC) – ethyl acetate 7:3, detection at UV 366 nm.