J. Planar Chromatogr. 15, 463-465 (2002). TLC of phenolic acids (3,5-dihydroxybenzoic acid, vanillic acid, p-coumaric acid, p-hydroxybenzoic acid, gentisic acid, caffeic acid, syringic acid, sinapic acid, ferulic acid, protocatechuic acid, 2,4-dihydroxybenzoic acid) on RP-18 (first development) and in the perpendicular direction on silica gel. One-dimensional TLC on RP-18 with methanol - water 2:3, on silica gel with toluene - dioxane - formic acid 7:2:1 and with a mobile phase I, a gradient of decreasing polarity and formic acid concentration. Detection under UV 254 and 366 nm and by coupling with bis-diazotized sulfanilamide.

leaves, inflorecences and rhizomes. J. Planar Chromatogr. 16, 230-236 (2003). Optimization of separation TLC of free phenolic acids and those released after acidic and basic hydrolysis (gallic, chlorogenic, protocatechuic, m- and p-hydroxybenzoic, vanillic, isovanillic, caffeic, gentisic, syringic, o-, m-, and p-coumaric, ferulic, salicylic, a- and g-resorcylic, sinapic and veratric acid used as standards) by one- and two-dimensional development on cellulose, polyamide 11 and silica gel with different mobile phases. Detection under UV 254 and 366 nm, then in daylight after treatment with diazotized sulfanilic acid, both with and without spraying with 20% sodium carbonate solution. Densitometry. Phenolic acids can be successfully separated on polyamide 11 with benzene - methanol - acetic acid 45:8:4.

J. Planar Chromatogr. 16, 377-380 (2003). TLC of diosmin on silica gel with chloroform - methanol - water 23:12:2 with chamber saturation with 25% NH3. Quantitation by densitometry at 344 nm. Repeatable and accurate results were obtained, limit of detection was 20 ng; satisfactory recovery (99.8 to 100.3%); linearity is given from 5 to 50 mg/mL. New and simple procedure.

CBS 90, 10-11 (2003). HPTLC of periwinkle cell samples on prewashed silica gel with ethylacetate - diethylamine 9:1 in horizontal developing chamber over 25 mm. Detection by radiation with short-wave UV 254 nm. Quantitative determination by fluorescence measurement at 254 nm or 365 nm.

CBS 88, 14-15 (2002). HPTLC of mushroom extracts on silica gel with dichloromethane - ethyl acetate - methanol 3:1:1 and HPTLC of hydroquinone, rutin, resorcinol, and ascorbic acid on silica gel with toluene - methanol - acetic acid 45:8:4 over 80 mm with chamber saturation. Determination of bioactivity with DPPH-biotest by spraying with 5 mg (2,2-di-(4-tert-octylphenol)-1-picrylhydrazyl in 10 mL acetone.

Chinese J. Trad. Pat. Med. (Zhongchengyao) 26 (8), Append. 9-11 (2004). TLC on silica gel previously immersed in 0.5 % NaOH solution, developed with 1) ethyl acetate - methanol - water 100:17:13; and 2) with the upper phase of toluene - ethyl acetate - formic acid - water 20:10:1:1. Detection by spraying with AlCl3 solution and under UV 365 nm. Identification by fingerprint technique and comparison with the standard. Quantification of scutellarin by HPLC.

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.

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.