J. Planar Chromatogr. 18, 34 -38 (2005). Considering the latest technical and methodological developments, modern high-performance thin-layer chromatography, also known as planar chromatography, is a reliable and powerful analytical technique, in full compliance with current good-manufacturing practice (cGMP). With the proper equipment TLC is the method of choice when many samples must be analysed at low cost per sample. Advantages of HPTLC are shown in the analysis of botanicals: 1) Identification (separation of Stephania tetrandra root extracts with tetrandrine as standard on silica gel with toluene - ethyl acetate - methanol -ammonia 100:100:50:3; detection under UV at 254 and 366 nm, under white light after derivatization with iodine, and under UV at 366 nm after derivatization with anisaldehyde. 2) Semi-quantitative assessments in process control and stability tests (separation of fatty acids of Saw Palmetto products on RP-18 by two fold development with dichloromethane - acetic acid - acetone 2:4:5. 3) Quantitfication of marker compounds, like curcumin measured at 366 nm/>400 nm on silica gel with toluene - acetic acid 4:1. 4) Choice of stationary phase (separation of flavonoids on conventional TLC plates and on HPTLC plates with formic acid - water - ethyl methyl ketone - ethyl acetate 10:10:30:50 and detection with natural products reagent; switching to HPTLC reduced analysis time to a quarter and gave sharper bands). 5) Choice of mobile phase; 6) Derivatization and 7) Chromatogram evaluation.

Chinese J. Chromatogr. 26 (1), 50-55 (2008). TLC of some endophytic fungi isolated by column chromatography from selected medicinal plants on silica gel plates with 1) chloroform - methanol 7:1, 2) chloroform - acetonitrile 7:3, 3) ethyl acetate - 2-propanol 19:1, 4) methylene chloride - tetrahydrofuran 3:1, 5) methylene chloride - methanol - dimethylformamide 90:9:1. Detection by spraying with 1 % vanillin sulfuric acid reagent after gentle heating. Also HPTLC on silica gel with chloroform - methanol 9:1. Detection by densitometry at 254 nm and 366 nm. If taxol was present, derivatization by spraying with 1 % vanillin sulfuric acid reagent and heating for 2 min, then detection under UV 366 nm and white light. Only 13 fungal species produced taxol in the artificial culture medium of the 20 screened fungi.

Planta Med. 71, 194-196 (2005). Analytical TLC of glaucopines A and B on silica gel with dichloromethane - methanol 19:1. Detection by spraying with 50 % sulfuric acid.

(Chromatographic determination of acetyldigoxin in quality control.) Dtsch. Apoth. Ztg. 123, 1022-1026 (1983). TLC of alpha-acetyldigoxin on silica with chloroform - acetone 1 3:9. Detection with HCl vapors and drying at 120 °C for 10 minutes. In situ evaluation.

Planta Med. 70, 993-1000 (2004). Preparative TLC of catuabine and its hydroxymethyl derivative 7-exo-hydroxy-N-methyl-catuabine on silica gel with dichloromethane - acetone 97:3 and toluene - acetone - methanol - ammonia 45:45:7:3. Detection under UV light at 254 and 366 nm and by spraying with potassium iodoplatinate reagent (0.25 mL of 5 % hexachloroplatinic acid solution mixed with 2.25 mL of 10 % potassium iodide solution and dissolved with 5 mL water).

J. Chromatogr. 268, 528-534 (1983). TLC of different drugs on silica. After development acc to Stahl and Clarke, the plates were sprayed with iodic reagent. Examination of the spots immediately after drying and after 1 and 24 h. The color reactions obtained with iodic acid reagent provide additional information to the chromatographic literature which nay be useful for tentatively identifying drugs separated by TLC.

Planta Med. 72, 187-189 (2006). Preparative TLC of shinpherocarpin, 7,4’-dihydroxy-2’,5’-dimethoxyisoflav-3-ene, and 7-hydroxy-4’-methoxy-3’-prenylisoflavone (5-deoxy-3’-prenylbiochanin A) on silica gel with hexane - dichloromethane 3:7 (multiple development). Detection under UV light at 254 nm.

J.A.O.A.C. 66, 1186-1195 (1983). TLC of PCP(I-II-phenylcyclohexyl)-piperidine and analogs on silica with a) methanol - NH3 100:1. 5, b) benzene - acetone - pyridine 16:8:1. Detection with iodoplatinate reagent or ninhydrin.