Chromatographia 21, 655-656 (1986). Use of naturally occurring Zeolite mineral as a new adsorbent for the TLC separation of food dyes.

CLB Chemie in Labor und Biotechnik 47, 262-263 (1994). HPTLC screening of carcinogenic amines in textiles on silica with dichloromethane - acetonitrile 5:1. Derivatization by diazotation and coupling with N-(1-naphthyl)-ethylenediammonium dichloride. Visual evaluation (pink to blue zones on a pale background). For confirmation of positive results a 15 step AMD gradient on silica from 80% dichloromethane - acetone 1:1 and 20% hexane to 20% dichloromethane - acetone 1:1 and 80% hexane follows. Alternative chromatography on silica with diisopropyl ether - pentane - diethyl amine 12:8:1. Quantification by densitometry (absorbance) at 200, 230, 280 and 360 nm (multi-wavelength-scan). The detection limit of 20 derivatized amines is between 20-200 ng and of not derivatized between 20-400 ng. Sample preparation includes treatment with dithionite reagent, cleaving azo dyes into their component amines. Very effective screening method. Similar topic published: "Identification and determination of carcinogenic amines of the MAK value list III A1/A2." in Int. Lab. Nov., 29-30 (1996); and "Nachweis und Bestimmung verbotener Amine aus der Spaltung von Textil-Azofarbstoffen. (Identification and determination of banned amines derived from textil azo dyes.) in GIT Fachz. Lab. Spez. Chromatogr. 2, 92-94 (1995).

J. AOAC Int. 91, 1387-1396 (2008). HPTLC on silica gel with chloroform - methanol 9:1 in the first direction for curcumin, demethoxycurcumin, bis(demethoxy)curcumin, and the synthetic dye metanil yellow, and with toluene - hexane - acetic acid 50:50:1 for sudan I and sudan IV in the second direction. Quantitative determination by absorbance measurement at 420 nm for curcumin and metanil yellow, at 491 nm for sudan I, and at 520 nm for sudan IV.

J. Planar Chromatogr. 28, 6-11 (2015). TLC of nine reactive dyes, seventeen fluorescent brighteners (nine of them are triazine-stilbene derivatives and eight of them are 2-aminodimethylterephthalate derivatives) and their intermediates (twenty four in number), all of them containing 4-amino-2,2,6,6-tetramethylpiperidine stabilizer fragment, on silica gel with n-propanol - ammonia - ethyl acetate 3:2:4 or heptane - propanol 1:1. Detection at UV 254 nm.

J. Planar Chromatogr. 30, 113-120 (2017). HPTLC of brilliant green, green fat, green S, iochrome black, oil red, natural red, rhodamine, patent blue, brilliant blue, brilliant black, azorubin, ponceau 4R, allura red, tartrazine, 1-aminoanthraquinone, (4-[2-pirydylazo]resorcinol), quinoline yellow, thymol blue and curcumin on RP-18 by isocratic elution with different concentrations of methanol in water (0-100 % v/v) with addition of 100 mM trifluoroacetic acid (TFA); and by gradient elution using a 2012 proposed horizontal developing chamber for stepwise gradient elution in reversed-phase mode, with different concentrations of methanol and buffer (pH=3.0, 3 mM citric acid and 1.5 mM disodium hydrogen phosphate in deionized water). When the citrate buffer was replaced by TFA the front of the mobile phase was more uniform and the phenomenon of flow of the mobile phase to the surface of the adsorbent layer was not observed; therefore, the substance zone was well shaped. The best gradient separation was obtained with a 4-step convex gradient: the concentrations of methanol in subsequent fractions of the mobile phase were 40, 60, 70, and 80 % (v/v) and the migration distances of the fractions were 10, 10, 20 and 30 mm, respectively. The total development distance was 70 mm. The results showed high repeatability within the same plate and between studies. The highest values of precision (%RSD >2 %) were obtained for the most strongly retained substances (oil red, dye No. 8, and fat green, dye No. 2).

The effect of support and the organic phase in the eluent. Chromatographia 25, 908-914 (1988). Determination of the lipophilicity of some photosynthetic pigments by reversed-phase TLC on silica, alumina, cellulose, polyamide and diatomaceous earth with water - acetone and water - ethanol. Investigation of the effect of support and the organic phase in the eluent.

J. Chromatogr. 538, 157-164 (1991). TLC of the commercial and CCC-purified substances on silica with acetone – chloroform – butyl amine 132:48:9. Spectrophotometry after band scraping.

Proc. 9th Internat. Symp. Instr. Chromatogr., Interlaken, April 9.-11., 305-310 (1997). OPLC of quinoline yellow, sunset yellow, cochineal red A, indigo carmine, tartrazine, amaranth, erythrozine, on silica with mixed ternary phases as eluent. Detection by densitometry. For quantification the following mobile phases were chosen as the best: NH3 - methanol - ethyl acetate 1:3:6 and NH3 - ethyl methyl ketone - butanol 2:3:5. Densitometry.