Acta Pharmaceutica Hungarica 66, 125-131 (1996). TLC of 20-hydroxyecdysone, 2-deoxy-20-hydroxyecdysone, and 20-hydroxyecdysone-22-benzoate on silica with ethyl acetate - methanol - NH3 17:5:3, dichloromethane - ethanol 17:3, chloroform - methanol - acetone 6:2:1, methanol - water 13:7. Detection with vanillin-sulfuric acid reagent, densitometry at 254 nm or 360 nm.

Acta Pharmaceutica Hungarica 67, 211-219 (1997). TLC of alkaloids on silica with hexane - ethyl acetate - dichloromethane - diethylamine - methanol - acetone 360:270:270:48:27:18 or 200:300:300:53:30:110. Quantification by densitometry at 280 nm.

Phytochemical Analysis 10, 26-31 (1999). TLC of various steroidal alkaloids on silica with chloroform - methanol 95:10. Detection with Dragendorff's reagent or with anisaldehyde/sulfuric acid. In some cases, the mobile phase was methylene chloride - methanol 9:1. Excellent conditions are given for the separation of steroidal alkaloids, such as solasodine.

by zonal micropreparative TLC. J. Planar Chromatogr. 14, 95-99 (2001). Micropreparative isolation of sanguinarine and chelerithrine by TLC on silica gel impregnated with pH 6 acetate buffer. Mobile phases were prepared by mixing a constant volume of acetate buffer with different volumes of methanol and water. Detection of the quaternary alkaloids under UV 366 nm or by spraying with potassium iodoplatinate reagent. Quantitation by densitometry in reflectance mode at 280 nm. Also TLC of berberine, coptisine, chelilutine, chelirubine with chloroform - methanol - acetic acid 82:15:3.

Proc. Intern. Symp. on Planar Separations, Planar Chromatography 2001, pp. 181-190. TLC and HPTLC of extracts of Papaver somniferum and codeine, narceine, morphine, thebaine, papaverine and narcotine as standards on silica gel with toluene - acetone - ethanol - 25% NH3 20:20:3:1. Detection with formaldehyde - sulfuric acid reagent (Marquis' Reagent). Quantitation by densitometry at 600 nm. Simple TLC method.

by thin-layer chromatography. J. Planar Chromatogr. 15, 289-293 (2002). Preparative TLC of a quaternary alkaloid fraction on silica gel with toluene - ethyl acetate - methanol 83:15:2. Detection by densitometry at 366 nm. Investigation of the effect of the procedure used on the preparative separation. The optimized steps were: the mode of application of the starting band to the layer; the effect of the number of developments on the separation of the bands in unidimensional multiple development (UMD); the effect of concentration overloading on the separation of the bands; and the effect of the volume of solution introduced to the adsorbent layer on the resolution of neighboring bands.

Planta med. 68, 435-439 (2002). TLC of 10-hydroxy-N(a)-demethyl-19,20-dehydroraumacline on silica gel with ethyl acetate - methanol - water - ammonia 70:20:10:1, chloroform - methanol - water - ammonia 50:45:5:1 and 50:40:10:1. Detection under UV light at 254 nm and after spraying with cericammonium sulfate (CAS) reagent.

J. Chromatogr. Sci. 43 (4), 183-194 (2005). HPTLC of selected alkaloid standards on RP18 W layer with various aqueous eluents containing an organic modifier and pH 3 buffer to suppress silanol ionization or an organic modifier and pH 8 buffer to suppress alkaloid ionization. Anionic ion pairs such as sodium dodecyl sulfate, octane-1-sulfonic acid sodium salt, pentane-1-sulfonic acid sodium salt, and bis(2-ethylhexyl)ortho-phosphoric acid are used to improve peak shape, efficiency, and selectivity. Amines (e.g., diethylamine, triethylamine, and tetrabutylamonium chloride) are incorporated into mobile phases to block surface silanols. The effect of chromatographic conditions on the separation of the investigated alkaloids is analyzed by the comparison of particular densitograms, asymmetry factor, or theoretical plate number. The best efficiency, peak symmetry, and separation selectivity of the investigated compounds is obtained through the addition of amine (especially diethylamine) to the mobile phases.