An improved analytical procedure. J. Planar Chromatogr. 17, 173-176 (2004). TLC of R,S-(+-)-ibuprofen and S-(+)-ibuprofen on silica gel prewashed with methanol - water 9:1 and impregnated with L-arginine by conventional dipping for 2 s in a 0.03 mol/L solution of the compound in methanol. One-dimensional development with acetonitrile - methanol - water 5:1:1 plus several drops of acetic acid to adjust the pH to 4.8, and two-dimensional chromatography with the same solvent mixture in two directions. Quantitation by densitometry at 210 nm.

cultivated in Poland. J. Planar Chromatogr. 18, 104-107 (2005). TLC and HPTLC of ginsenosides (Rg1, Re, Rf, Rb1, Rc, Rb2, and Rd as standards) on silica gel with chloroform - methanol - ethyl acetate - water - hexane 10:11:30:4:2. OPLC on HPTLC silica gel with the same mobile phase but containing ethyl acetate or propyl acetate. Detection by spraying with Godin’s reagent (5 % sulfuric acid and 1 % vanillin in ethanol) and heating at 105 °C for 10 min. Densitometric evaluation by absorbance measurement at 540 nm.

J. Planar Chromatogr. 18, 372-376 (2005). HPTLC of sildenafil in four commercial products and three aphrodisiac herbal preparations on silica gel after pre-saturation with chloroform - methanol - diethylamine 90:10:1. Quantitative determination by absorbance measurement at 305 nm. Recovery was 100.6 and 98.2 % for pure and spiked samples.

J. Planar Chromatogr. 18, 234-239 (2005). TLC of Evolvulus alsinoides extracts and the marker EA 1, i.e. 3beta,23,24-trihydroxyolean-12-en-28-oic acid, on silica gel with n-hexane - ethyl acetate 7:3 in a saturated chamber. The marker EA 1 was detected under UV light at 366 nm as a yellow fluorescent band of Rf 0.8. Quantitative determination by absorbance measurement at 232 nm (=UV max of EA 1). Limit of detection 11.6 ng; satisfactory recovery from 93.3 to 96.6 %. The marker was isolated from the aerial parts of Evolvulus alsinoides by preparative TLC.

Abstract G-33, IPC (2005). HPTLC of epalrestat in plasma on silica gel with ethyl acetate - toluene - acetic acid 30:20:1. Nitrofuranloin was used as internal standard. Quantitative determination by absorbance measurement at 390 nm. Linearity was obtained the range of 0.01-0.20 µg/mL with recovery of 99-107 %. The method was validated as per ICH guidelines.

J. Planar Chromatogr. 18, 19-22 (2005). TLC of desloratadine (8-chloro-6,11-dihydro-11-(4-piperidinylidene)-5H-benzo[5,6]cyclohepta[1,2-b]pyridine) on silica gel with ethyl acetate - n-butanol - 25% ammonia - methanol 21:5:4:5. Quantitative determination by absorbance/reflectance measurement at 279 nm. Peak area was linearly dependent on the amount of desloratadine within the range of 1500 to 5000 ng/spot. The relative process standard deviation was 1.78 %.

CBS 96, 11-13 (2006). HPTLC of isopropylthioxanthone (ITX) in food, on silica gel in horizontal developing chamber with toluene - n-hexane 4:1 over 50 mm. Quantitative determination by fluorescence measurement at UV 254/>400 nm. Polynomial calibration via peak height, working range was 20 - 200 µg/kg. LOD is 64 pg (n=3) and in spiked fatty matrix 1 µg/kg. Positive findings were confirmed by ESI-MS in selective ion monitoring mode at m/z 255 and 277 using a plunger-based extraction device. Further confirmation by DART directly coupled to TOF-MS.

Indian Drugs 42 (10), 650-653 (2005). A simple rapid, precise and cost-effective HPTLC method has been developed for the determination of ursolic acid in Oscimum sanctum (Tulsi) leaves and its formulations (Tulsi ghan tablets and Tulsi capsules). HPTLC on silica gel with toluene - ethyl acetate - acetic acid 30:3:1. Detection with anisaldehyde in sulphuric acid reagent followed by heating in an oven at 110 °C. Quantitative determination by absorbance measurement at 580 nm. Linearity of the detector response was given in the range of 40 - 280 ng. LOD was 8 ng. The correlation coefficient obtained from linearity was 0.9985. The standard error was 26.511. The mean assay values of ursolic acid wa found to be 3.485 mg/g, 0.553 mg/g and 3.221 mg/g in tulsi ghan tablets, tulsi capsule and tulsi leaves respectively.