J. Planar Chromatogr. 5, 200-204 (1992). TLC of red bell pepper extract and ß-carotene on silica with ethyl acetate - dichloromethane - hexane 24:56:20 (single development); and a variety of solvent combinations (multiple development); scanning at 450 nm (absorbance). The results show a general instability of carotenoids under conditions typically employed in TLC. Rigorous exclusion of oxygen and light would prevent the alteration of carotenoids, however, not particularly easy to achieve in practice. The use of layers impregnated with antioxidant is one possible solution. Great caution should be exercised when reviewing data TLC for the identification and quantification of carotenoids from plant material.

Biochemical Systematics and Ecology 23, 267-275 (1995). TLC of anthraquinones on silica with chloroform - petrol ether 1:1, chloroform - ethyl acetate 1:1 and benzene - petrol ether - ethyl acetate 1:2:1. Visualization under UV 254 and 366 nm.

J. Agric. Food Chem. 49, 5484-5488 (2001). TLC of b-carotene and some xanthophylls on silica gel with acetone-n-hexane 3:7 after a prerun in 2.5% solution of citric acid in methanol. Quantitation was performed with an imaging densitometer.

1. ß-Carotene degradation. J. Agric. Food Chem. 38, 237-243 (1990). TLC of aurochrome, mutatochrome, neo-T-5,6,5',6'-diepoxy-ß-carotene on aluminium oxide with acetone - petrol ether 40°C 4:95 in the darkness; visualization with hydrochloric acid for identification of epoxy groups.

J. Liq. Chrom. & Rel. Technol. 20, 101-110 (1997). Development of a quantitative HPTLC method. HPTLC of lycopene, carotene and synthetic certified food colors (Blue No. 1, Green No. 3, Yellow No. 5 + 6, Amaranth, Red No. 3, 4 + 40) on silica gel, prewashed with dichloromethane - methanol 1:1, in a vapor saturated chamber with petroleum ether - dichloromethane 17:3 (for lycopene) and butanol - acetic acid - water 4:1:5 for Red no. 40, butanol - ethanol - water - ammonia 10:5:5:2 for Yellow No. 5 and Blue No. 1. Quantification by densitometry at e.g. 385 nm, 500 nm and 630 and 420 nm, respectively.

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.