J. Planar Chromatogr. 30, 440-452 (2017). For electroseparation experiments in a commercially available, open-air electrophoresis box, thirteen types of separation layers (filtrating paper, office paper, chromatography paper, Japanese paper for aircraft paper models, potato starch on cellulose support, common HPTLC glass plates coated with cellulose, silica gel, RP-18W, and aluminum oxide as well as glass-based nutrient agar layers) were investigated. The best separation was observed for the cellulose pre-coated TLC layer and the starch layer on filtrating paper support. The study revealed substantial differences between the electrophoretic migration of target dyes within cellulose type layers and also in comparison to the remaining stationary phases studied. Combined planar electrophoresis–electrochromatography of methyl red and ponceau R colorants on active thin-layers composed of starch powder on cellulose strips and agar layer on glass-based support connected with electrolyte containers. The resulting dye pattern on active layers was acquired using an office scanner.

Analyst 113, 1613-1623 (1988). HPTLC on silica with 7 solvent systems. Measurement by densitometry at 436 nm. Limits of detection, 3 ng. Proposal of a sampling and anlysis scheme to determine dyes in the air. Modification of the screening technique for dyes.

Chinese J. Chem. (Huaxue Tongbao) (5), 40-42 (1993). TLC of the impurities in crystal violet dye on silica with methanol - water - hydrochloric acid of butanol - butanoic acid - acetic acid - water systems. Quantification by HPLC.

27 and 28 (phloxine B) by thin-layer chromatography and video densitometry. J. Planar Chromatogr. 10, 157-162 (1997). Description of a simple and rapid TLC-videodensitometric method for the in situ quantification either of lower halogenated subsidiary colors (LHSC) or of the ethyl ester (EE) in multiple dye samples on the same analytical TLC plate. HPTLC of 2',4',5'-tribromo-4,5,6,7-tetrachlorofluorescein, LHSC and EE of D&C Red Nos. 27 and 28 on silica with acetone - chloroform - n-butylamine 44:16:3 for LHSC and chloroform - acetic acid 4:1 for EE. Evaluation by videodensitometry at 302 nm. This method was found to be applicable for use in routine batch-certification analysis.

J. AOAC Int. 90, 291-298 (2007). TLC of 4-carboxyl-2,6-dinitrophenyl azo hydroxynaphthalenes (6-hydroxy-, 8-hydroxy-5-(4-carboxy-2,6-dintrophenyl azo)-naphthalene, 6-hydroxy-5-(4-carboxy-2,6-dintrophenyl azo)-naphthalene-2-(propan-2-oic acid), 6-hydroxy-5-(4-carboxy-2,6-dintrophenyl azo)-naphthalene-2-(butan-2-one)) on silica gel (impregnated by development with a solution of 5% liquid paraffin in n-hexane) with aqueous mixtures of methanol, acetone, and dimethylformamide. Visual evaluation in white light.

J. AOAC Int. 91, 1196-1202 (2008). Thermostated micro HPTLC of Spirulina maxima dyes on RP18 with acetone - n-hexane 3:7 in a homemade temperature-controlled removable horizontal micro TLC chamber at 40 °C with chamber saturation. Detection by direct digital scan under visible light conditions. Experimental data indicated that under such conditions, with an office scanner used for chromatogram digitalization, spot quantification could be accurately performed within the analyte mass range of two orders of magnitide.

J. Chromatogr. Sci. 54 (8), 1421-1427 (2016). Development of a simple, cost-effective and reliable method for quantification of naphthoquinones, found as natural red color pigments in roots of Arnebia benthamii (Wall. ex G.Don) I.M. Johnst., by HPTLC on silica gel with hexane – ethyl acetate – methanol 16:3:1. Determination of shikonin (hRf 37) and β,β-dimethylacryl shikonin (hRf 58) in the methanol extract by densitometry at 520 nm. The linearity was 0.1-8 µg/zone. The average recovery was >97 % for both and the intraday and interday precision for the quantification of naphthoquinones was good (%RSD <2.0 %). The LOD were 13 and 15 ng/zone for shikonin and β,β-dimethylacryl shikon and the LOQ were 39 and 44 ng/zone, respectively.

J. of Natural Products 51, 1251-1256 (1988). TLC of (+)-S-skyrin, skyrin, protohypericin and hypericin on silica with benzene - ethyl acetate - acetone - acetic acid 12:6:1:1 or benzene - ethyl acetate - acetic acid 10:5:3.