J. Chromatogr. Sci. 38, 145-150 (2000). TLC on silica gel and alumina impregnated by overnight predevelopment in n-hexane - paraffin oil 19:1, resp. on RP-18. Development with water containing various concentrations of methanol, acetone, THF and dioxane in sandwich chambers in the dark; finall development with water - THF 3:7. Evaluation visually and quantification by densitometry at 340 and 370 nm. - TLC - FTIR on-line and off-line coupling.

J. Liq. Chrom. & Rel. Technol. 27, 1579-1592 (2004). TLC of an orange color standard before and after saponification (as beta-cryptoxanthin) on RP18 with acetonitrile - acetone - n-hexane 11:7:2 and acetone - water 9:1. Measuring the visible absorption spectra in the range of 370-700 nm by scanning densitometry with its maximum absorption wavelength at 455 nm.

J. Chromatogr. A 1266, 168-174 (2012). RP-TLC plates modified with C18, C8 or C2 are available on the market, however, RP-plates with tunable polarity have not been reported. Because of the limited variety of RP-plates mobile phase optimization is needed which is often time consuming. The presented polarity-adjustable RP-UTLC plates simplify the mobile phase screening process and expand the selection of reversed phase plates. The plates were prepared using the glancing angle deposition (GLAD) technique to deposit SiO2 nanopillars on glass plates and functionalized with octadecyltrichlorosilane for hydrophobicity. By O2 plasma treatment the silane carbon chain was shortened and COOH groups were introduced to the surface, producing plates with finely tunable polarities. Confirmation of the tuning of surface polarities by measurement of retention behavior changes in the separation of a model dye mixture of Sudan blue and Sudan IV, the elution order of which reversed as a result of the change in surface polarity. Testing on commercial RP-plates showed no change in the separation behavior which proves that plasma treatment of GLAD structures with highly accessible surfaces improves control over interfacial properties, producing better reverse phase separations. UTLC of Sudan blue and Sudan IV in toluene on the new RP-UTLC plates in horizontal developing chamber with acetonitrile, detection in visual light by recording of the development process by video camera).

Biochemical Systematics and Ecology 20, 771-781 (1992). 2D-TLC of anthocyanins on cellulose with butanol - acetone - water 4:1:5 (top phase) for the first direction and acetone - hydrochloric acid - water 15:3:82 for the second.

J. Planar Chromatogr. 17, 54-57 (2004). TLC of food pigments (patent blue V, quinoline yellow, brilliant blue FCF, tartrazine, azorubine, ponceau 4 R, curcumine, indigo carmine, cochineal, methyl violet, mixed carotenes, plain caramel, erythrosine B, orange yellow S) and artificial sweeteners (aspartame, acesulfame, sodium cyclamine) and benzoic acid on silica gel. Pigments were developed with isopropanol - 12.5 % ammonia 5:1; sweeteners and benzoic acid were developed with ethanol - isopropanol - 12.5 % ammonia 10:40:1. Derivatization with a solution of 0.04 g bromocresol green in 100 mL ethanol containing 0.1 M sodium hydroxide.

J. Planar Chromatogr. 25, 542-547 (2012). HPTLC of tartrazine in mustard on silica gel with isopropyl alcohol - ammonia 7:3. Quantitative determination by absorbance measurement at 425 nm (1) and by digital processing using a TLC scanner at an optical resolution of 300 dpi in visible mode followed by image digitalization (2). The hRf of tartrazine was 61. Linearity was in the range of 32-878 ng/zone using (1) and 92-600 ng/zone using (2). Limits of detection and quantification were 5 and 11 ng/zone using (1) and 51 and 74 ng/zone using (2). Average recovery with both methods was greater than 100 %. Lower contents of tartrazine in mustard samples were determined when TLC image processing was applied for quantification probably due to poor sensibility of calibration with this method.

J. Planar Chromatogr. 29, 446-452 (2016). HPTLC of brilliant blue (1), tartrazine (2) and carmoisine (3) on polyaniline-modified silica gel (prepared by in-situ oxidative polymerization of aniline in the presence of different amounts of silica gel using potassium persulfate as the oxidizing agent) with methanol - water 1:9. The hRF values for (1) to (3) were 5, 96 and 90, respectively. A better separation efficiency was observed by modifying silica gel with polyaniline as compared to the conventional silica gel layer._x000D_

(Chinese). Chinese J. Chem. Reag. 9, 371-374 (1987) (Huaxue Shiji). TLC on silica with benzene - carbon tetrachloride - acetic acid - acetone 50:75:0.8:3.8. Quantification by spectrophotometry at 425 nm after elution with acetone.