J. Planar Chromatogr. 22, 43-47 (2009). HPTLC of alpha-solanine and alpha-chaconine on silica gel with dichloromethane - methanol - 2.5 % ammonia 175: 75:11 in a horizontal chamber saturated for 15 min. After drying and heating at 90 °C for 25 min detection by dipping twice in modified Carr-Price reagent (antimony(III) chloride in acetic acid - dichloromethane), followed by heating at 110 °C for 3 min. Quantitative determination by absorbance measurement at 560 nm. Linearity was between 30 and 700 ng. The limit of detection was 5-20 ng/zone depending on the sample matrix, the limit of quantification was 30 ng/zone. The ratio of alpha-chaconine and alpha-solanine was between 4:1 to 2:1 for all analyzed samples.

J. Chromatogr. A 1112 (1-2), 156-164 (2006). HPTLC of glucosamine in a dietary supplement containing dried extracts of the main plants traditionally used for rheumatic disorders, on silica gel with a saturated mixture of 2-propanol - ethyl acetate - ammonia (8 %) 1:1:1. Detection by dipping into a modified anisaldehyde reagent and heating at 120 °C for 30 min in a drying oven. Quantitative determination by absorbance measurement at 415 nm. Validation of the method by applying the novel validation protocol proposed by a commission of the Société Française des Sciences et Techniques Pharmaceutiques. Relative standard deviations for repeatability and intermediate precision were between 4.9 and 8.6 %, accuracy was good, the two-sided 95 % beta-expectation tolerance interval was within the acceptance limits of 85 and 115 % on the whole analytical range (800 - 1200 ng of glucosamine).

J. Planar Chromatogr. 21, 263-265 (2008). HPTLC of nimbolide on silica gel in a twin trough chamber with ethyl acetate - hexane 1:1. Quantitative determination by absorbance measurement at 254 nm. The limits of detection and quantification were 3.3 and 1.0 µg/spot, respectively.

J. Agric. Food Chem. 55, 7489-7494 (2007). HPTLC of fruit powder and commercial products of Noni (Morinda citrifolia) on silica gel with chloroform – methanol 9:1 or chloroform – methanol – water 13:6:1. Detection under UV 254 and 366 nm after spraying with vanillin reagent (1 % vanillin in ethanol containing 2 % sulphuric acid), followed by heating at 105 °C. The following compounds were identified as markers (hRf): ursolic acid (60), linoleic acid (55), scopoletin (53), 3-methyl-1,3-butanediol (27).

Ind. J. of Pharma Sci. 70(6), 844-847 (2008). HPTLC of plumbagin in alcoholic root extracts of Plumbago indica and Plumbago zeylanica on silica gel with n-hexane - ethyl acetate 4:1. The hRf value of plumbagin was 67. Quantitative determination by absorbance measurement at 265 nm. Plumbago indica showed significantly higher plumbagin contents than P. zeylanica. The HPTLC method was the method of choice for simultaneous analysis of several samples, whereas the RP-HPLC method was very sensitive.

Anal. Chem. 81, 8426-8433 (2009). HPTLC of zeaxanthin, cryptoxanthin, beta-carotene, lutein and pollen extracts on silica gel with tetrahydofuran - methylene chloride - n-hexane by automated multiple development. Quantitative determination by absorbance measurement at 425 nm, which has to be accomplished within 5 min after development due to the fast bleaching of the carotenoid color. The analysis of carotenoids in pollen extracts was confirmed by resonance Raman data measured directly on the HPTLC plates.

J. AOAC Int. 92, 725-729 (2009). HPTLC of acrylamide extracted from coffee samples on silica gel with ethyl acetate - tert. butyl methyl ether 4:1 in a twin trough chamber or automatic developing chamber. Pre-chromatographic in situ derivatization of the extracts (applied as area) by overspraying with dansulfinic acid produced the fluorescent dansylpropanamide band. Quantitative determination by fluorescence measurement at 254/>400 nm. The limit of quantification was 48 µg/kg. The linearity over the whole procedure showed determination coefficients between 0.9995 and 0.9825 (n = 6). The within-run precision (%RSD, n = 6) of the chromatographic method was 3%. Commercial coffee samples analyzed showed acrylamide contents between 52 and 191 µg/kg, which was in correlation with amounts reported in publications.

60th Indian Pharmaceutical Congress PG-262 (2008). HPTLC of withaferin A in Ashwagandha on silica gel aluminum layer with toluene - ethyl acetate - formic acid 5:5:1. Quantitative determination by absorbance measurement at 214 nm. The chromatograms of the tablet formulation showed a zone corresponding to standard withaferin A (hRf value 37) indicating the presence of the same in the herbal formulation. Linearity was in the range of 50-500 ng/spot. The concentration of withaferin A was 8.07 µg/tablet and 0.00134 % w/w in the tablet formulation.