Physical Testing and Chem. Anal., Part B: Chem. Anal. 45 (1), 14-18 (2009). TLC of ink extracts on silica gel with n-butanone - ethanol - water - acetic acid 14:4:6:1. Detection in visble light and identification by comparison of spot colors and hRf values. The method was used for the identification of 37 different black ink samples from gel pens from different sources, which could then be classified into 13 categories.

J. Liq. Chromatogr. Relat. Technol. 39, 549-557 (2016). Review of the use of TLC and HPTLC for the analysis of inks in forensic applications, including sample preparation, layers, sample application, detection, documentation and results interpretation. The author also described the application of TLC in food dye analysis as well as future trends in the field.

J. AOAC Int. 3, 686-694 (2018). HPTLC of 11 chemical dyes, namely, Sudan I (1), II (2), III (3), and IV (4); 808 Scarlet (5); Sudan Red 7B (6); malachite green (7); Basic Orange 2 (8); auramine (9); Orange II (10); and erythrosine (11) in traditional Chinese medicine raw materials and Chinese patent medicines on silica gel with cyclohexane – trichloromethane 7:3 saturated with ammonia vapor for the separation of (1) to (8). The plate was developed a second time in the same direction with ethyl acetate – alcohol – water – aqueous ammonia 16:4:2:1 for (9) to (11). Quantitative evaluation by densitometry from 200 to 700 nm. The hRf values for (1) to (11) were 74, 78, 74, 68, 44, 23, 8, 2, 56, 28 and 20, respectively. The LODs were 2 to 3 ng/zone, except for (6) 10 ng/zone. HPTLC combined with ESI-MS was assessed for proof of the effective separation of dyes and their identification in herbal matrices.

J. Chromatogr. 481, 331-342 (1989). TLC on silica with propanol - water - acetic acid in various proportions. Determination of their Rm values. Studies of linear free energy relationship with some electronic, steric and lipophilic parameters. Attempt of establishing the nature of dye-substrate adsorption by correlation with the theoretical charge densities. Studies showed that the steric factor has the greatest influence on the chromatographic behavior.

Chinese Anal. Chem. (Fenxi Huaxue) 21, 365 (1993). Ion-pair reverse-phase TLC of title compounds on a mixture of cross-linked polystyrene beads and silica with acetonitrile - water, containing ß-naphthalene monosulfonic acid and perchloric acid in concentrations between 0.005 - 0.045 mol/L. Discussion of the dependence of Rf values on the structure of the compounds, and the effects of solvent composition and pH value on Rf value.

Lab. Spe. Separation 1, 28-29 (2000). HPTLC of 8 disperse dyes (blue 1, blue 35, blue 106, blue 124, yellow 3, orange 3, orange 37/36, red 1) on silica gel with chloroform - ethyl acetate - n-hexane 6:3:2, bandwise application. Mixtures with coeluting dyes can be investigated using the AMD technique with multiple development (in 20 steps) with a gradient from methanol via dichloromethane to n-hexane. Quantification by densitometry at 254 nm.

J. Planar Chromatogr. 23, 219-224 (2010). TLC of carotenoids (lutein, beta-carotene), astaxanthin and tannin on silica gel with petroleum ether - diethyl ether - acetone 15:3:2 in a twin-trough chamber saturated for 30 min at room temperature. Quantitative determination by densitometric absorbance measurement at 450 nm. The hRf values of lutein in tea, mulberry, and cassava leaf were 19, 22, and 19 and corresponded to lutein standard. The least polar zone had an average hRf value of 98, 98, and 96 for tea, mulberry, and cassava leaf, respectively, and was identical with beta-carotene standard.

J. Chromatogr. A 1572, 137-144 (2018). Development of a method for the analysis of anthocyanes within the foodstuffs of plant origin by TLC on RP-18 phase (which ensures mixed-mode retention mechanism with the localized adsorption on the non-bonded silanols) with acetic acid as the mobile phase component, using two anthocyanins (cyanin and keracyanin) and two anthocyanidins (pelargonidin and delphinidin) as phytochemical standards. By triple development, distinct and symmetrically shaped chromatographic zones were obtained. Further analysis of the products of hydrolytic degradation of the test anthocyanins by MS. Identification of the hydrolytically split fractions by using the p-aminobenzoic acid reagent. Investigation of the calibration curves for cyanin, keracyanin, pelargonidin and delphinidin, and the respective LOD and LOQ values. Application of the method to identify and quantify cyanin, keracyanin, pelargonidin and delphinidin in selected alimentary products (syrups, juices and herbal infusions).