J. AOAC Int. 89, 995-998 (2006). HPTLC of phenobarbital on silica gel, prewashed with methanol and then acetone, using dichloromethane - ethyl acetate - formic acid 95:5:1 in a horizontal chamber. Quantitation by densitometry in the absorbance/reflectance mode at 210 nm. The validity of the HPTLC-densitometric method was established through a study of linearity, sensitivity, accuracy, and reproducibility.

J. Liq. Chromatogr. Relat. Technol. 28, 325-334 (2005). TLC of carthamus yellow in 35 commercial foods, on RP-18 with 2-butanone - methanol - 5 % sodium sulfate - 5 % acetic acid 3:2:5:5 without chamber saturation. Measurement of visible absorption spectrum using scanning densitometry.

Indian J. Pharm. Sci. 68 (6),788-789 (2007). HPTLC of etorocoxib in dosage forms on silica gel with chloroform - methanol - toulene 2:1:2. The plate was scanned at 289 nm for quantitative evaluation. The hRf value of etorocoxib was 58. The method was linear in the range of 100 - 600 ng/spot.The method was validated for accuracy, precision and repeatability. It was found suitable for routine quality control of formulations.

J. Liq. Chromatogr. Relat. Technol. 29, 2071-2082 (2006). TLC of S-(+)-naproxen on silica gel (prewashed with methanol - water 9:1 and impregnated with a 0.03 mol/L solution of L-arginine in methanol by dipping for 2 s at 22 +/- 2 °C) with acetonitrile - methanol - water 5:1:1.5 containing several drops of acetic acid to fix the pH at 4.8; and two-dimensional development with acetontrile - methanol - water 10:2:3. Densitometric evaluation at 235 nm.

J. Planar Chromatogr. 20, 411-417 (2007). HPTLC of sucralose in dietetic products on silica gel impregnated with 0.1 M dipotassium hydrogen phosphate solution, and on amino phase with acetonitrile - water 17:3. Also a mixture of sucralose, sucrose, glucose, fructose was separated on amino phases with acetonitrile - water 3:1. Detection by dipping in 2-naphthol sulfuric acid reagent and aniline diphenylamine ortho-phosphoric acid reagent, followed by heating at 120 °C. Post-chromatographic derivatization on aluminium-backed amino plates was performed by heating the plate 190 °C for 20 min. Evaluation under UV light at 366 nm. For fluorescence enhancement the amino plate was dipped into a 1:2 solution of paraffin in n-hexane. Densitometric quantification by fluorescence measurement at 366 nm and by absorbance measurement at 500 and 405 nm.

J. Planar Chromatogr. 20, 227-230 (2007). When the components of a reaction mixture cannot be quantified by UV-visible spectrophotometry because of overlapping of their absorption bands, the components can be separated and quantified by spectrodensitometric thin-layer chromatography (SDTLC). As example serves an aminolysis reaction mixture. TLC of imidazolidine and 1-(p-chlorophenyl)-2-phenyl-3-methylimidazoline on silica gel in a twin-trough chamber saturated for 5 min with chloroform - methanol 4:1 for the first development to a distance 55 mm, and after drying development with benzene to a distance of 65 mm. Densitometric scanning at 260 nm in absorption mode.

J. Sep. Sci. 30, 2092-2096 (2007). HPTLC of flavonoids in Bauhinia variegata, Bacopa monnieri, Centella asiatica, Ginkgo biloba, Lonicera japonica, Rosa bourboniana, Rosa brunonii, and Rosa damascena on RP-18 with two-fold development with water (5 % formic acid) – methanol 7:3 and water (5 % formic acid) – methanol 1:1 as mobile phases. Quantitative determination by absorbance measurement at 280 nm. The hRf values of apigenin (1), quercetin (2), rutin (3), luteolin (4), and quercitrin (5) were 19, 29, 34, 51, and 63, respectively. Linearity was between 150 and 800 ng/zone for (1) and (3) and between 200 and 1000 ng/zone for (2), (4) and (5). The limits of detection and quantification for (1) – (5) were 30 and 166 ng/zone, 40 and 200 ng/zone, 20 and 150 ng/zone, 40 and 200 ng/zone, and 40 and 200 ng/zone, respectively. Recovery was between 97 and 99.8% for (1) – (5).

J. Planar Chromatogr. 20, 293-301 (2007). TLC of candesartan, eprosartan, losartan, telmisartan, and valsartan on silica gel, aluminum oxide, amino-, cyano-, and diol-phase in a horizontal chamber in sandwich technique. Diol-phases were developed with hexane - isopropanol - formic acid 40:60:1, cyano-phases with hexane - dioxane - formic acid 30:70:1. Detection and quantification at 254 nm.