J. Chromatogr. A 1572, 152-161 (2018). Description of a novel application of HPTLC for separation and quantification of eight food colors (amaranth, allura red, erythrosine, fast green, indigo carmine, quinoline yellow, sunset yellow and tartrazine) and four intense sweeteners (acesulfame, aspartame, saccharin and neohesperidin) on silica gel with acetonitrile – water - ethyl acetate - 10 % aqueous ammonia 9:1:1:1. Quantitative determination by densitometry at 210, 295, 450 and 550 nm. The LOD and LOQ ranged from 0.2 to 10 ng/zone and from 1 to 30 ng/zone, respectively. The correlation coefficient (r2) values for the calibration curves were ≥ 0.9973 for all the additives. The recovery of different additives obtained from food products, beverages and pharmaceuticals ranged from 96.6 to 106.7 %.

The topics include evolution from TLC to HPTLC, mechanization of TLC, spectrophotometric detection, comparison with HPLC applications..

CBS 89, 12-15 (2002). HPTLC on silica gel with chloroform - methanol - water - ammonia 24% 65:30:4:2 over 90 mm with chamber saturation for 30 min. Detection by dipping in CuSO4/H3PO4 reagent for 8 s followed by heating at 170 °C for 10 min. Quantitative determination by absorbance measurement at 500 nm. Comparising operating costs the HPTLC analysis appears preferable for quality control of samples with known content. HPLC is more cost effective for the analysis of samples with unknown content.

CBS 88, 7 (2002) HPTLC of E 110 Yellow orange S, E 104 Quinoline yellow, E 124 Cochineal red, E 132 Indigotine I, E 151 Brilliant black BN on RP-18 W with methanol - 5 % aqueous sodium sulfate solution 3:4. Identification based on Rf-values, documentation under white light.

CBS 86, 10-12 (2001) HPTLC of valerian root extracts on silica gel (prewashed with methanol) with chloroform - ethyl acetate - propanol 15:10:1. Detection by dipping for 1 s in 15 % sulfuric acid in methanol followed by heating at 120 °C for 10 min and cooling to room temperature. Evaluation with video technology (VideoStore/VideoScan).

CBS 93, 2-4 (2004). HPTLC of signaling ceramides on silica gel with a 7 step gradient from methanol over dichloromethane to n-hexane over 42 min. Detection by dipping in manganese chloride reagent for 1 s, followed by drying at 120 °C for 20 min. Quantitative determination by absorbance measurement at 550 nm and Michaelis-Menten regression 2 via peak area. Signaling ceramides are separated from other lipids (shingomyelin, phosphatidylcholine, cholesterol) contained in cellular lipid extracts. Comparison with determination of ceramide formation via isotope labeled standards and conventional TLC method.

J. Planar Chromatogr. 17, 61-64 (2004). HPTLC of celecoxib and loratadine (as internal standard) on silica gel after prewashing and bandwise application with n-hexane - ethyl acetate 3:2 in a twin-trough chamber and equilibration for 10 min. Quantitative determination at 262 nm. Mean recovery 100.03 %.

J. Planar Chromatogr. 17, 335-341 (2004). TLC and HPTLC of 29 ecdysteroids (e. g. 20-hydroxyecdysone, polypodine B, 2-deoxyintegristerone, ajugasterone C, isovitexirone, muristerone A, turkesterone, makisterone C, rubrosterone, poststerone, ecdysone, herkesterone) on silica gel, RP-18, and cyano phase with four mobile phases enabling separation of all the ecdysteroids from each other in at least one system. Detection under UV light at 254 nm or by use of vanillin-sulfuric acid spray reagent. After spraying the spots were either observed in daylight or at 366 nm. Quantitative determination by reflectance-absorbance measurement at 254 nm.