IPC 56th 2004, Abstract No. G-18. Curculigo Orchioides (Amary llidaceae) is used in various ayurvedic formulations. The rhizomes contain about 5.78 % total phenolis, gallic acid being the major component of the alcoholic extracts. HPTLC of gallic acid on silica gel with toluene - ethyl acetate - glacial acetic acid 25:15:1. The Rf valueof gallic acid was 0.19, the linearity range of 150-750 ng/spot. Rhizomes were found to contain 2.54 % gallic acid, formulations contained 5.13 % gallic acid, recovery was 99.5 %.

IV. Comparison of separation of studied bile acids by the use of cluster analysis. J. Liq. Chrom. & Rel. Technol. 27, 2987-2995 (2004). TLC of bile acids (cholic, glycocholic, glycolithocholic, deoxycholic, chenodeoxycholic, glycodeoxycholic, and lithocholic acid) on silica gel and a mixture of silica gel and Kieselguhr with n-hexane - ethyl acetate - acetic acid in various volume compositions. Detection with 10 % aqueous sulfuric acid followed by heating at 120 °C for 20 min. On silica gel the separation of glycocholic from glycodeoxycholic acid was difficult, on the mixed silica gel - Kieselguhr layer the separation of cholic acid from glycolithocholic acid. The obtained results indicate that similar analysis can be an alternative method for the estimation of chromatographic separations of studied bile acids.

Indian Drugs 42 (7), 424-427 (2005) HPTLC of fexofenadine HCl from tablet dosage form on silica gel with dichloromethane - methanol 13:7. Quantitative determination by absorbance measurement at 260 nm. The linear detector response was observed between 0.2 and 1.0 µg. The method was validated to determine its accuracy and precision. The LOD was found to be 0.08 ng/µL, LOQ was 0.02 ng/µL. The recovery was carried out by standard addition method and was found to be 100.82 %.

The Royal Society of Chemistry, Cambridge 2005, ISBN 0-85404-535-X This book covers basic theory, concepts and practice of modern thin-layer chromatography. The author summarizes current knowledge obtained by many researchers working on qualitative and quantitative planar chromatography. The manual consists of eight chapters describing each step of typical planar chromatographic process with separate sections devoted to key analytical problems like stationary phase choice and pretreatment, mobile phase optimization, sample preparation and application, plate development and finally spot visualization, detection and quantification. The compact form of this work makes it a really simple, helpful and comprehensive introduction to modern thin-layer chromatography.

Indian J. Pharm. Sci. 69(4), 589 (2007). HPTLC of ropinirole on silica gel with methanol - acetone 4:1. Aripiprazole was used as internal standard. Under chromatographic conditions both ropinirole and aripiprazole were well separated. Evaluation under UV 254 nm. UV spectrometry was carried out at 250 nm.

CBS 100, 13-15 (2008). HPTLC of caffeine on silica gel with ethyl acetate - methanol - 25 % ammonia 90:15:1 (for samples of energy drinks) or chloroform - ethanol - 37 % acidic acid - acetone - water 54:27:10:2:2 (for samples of headache tablets). Detection under UV 254 nm. Quantitative determination by absorbance measurement at UV 274 nm. Automated online extraction with an HPTLC/MS interface connected to a ESI mass spectrometer. Without any internal standard the caffeine mass signal was recorded in the selected ion monitoring mode at m/z 195 [M+H]+. The method was validated. Repeatability was 5.6 % (%RSD, n=6) and reproducibility of the plate mean value was 1.5 % (%RSD, n=3).

J. Pharm. Biomed. Anal. 18, 271-274 (1998). HPTLC of cephalexin on silica gel (prewashed with the mobile phase) with ethyl acetate - acetic acid - water 7:2:1. Quantitative determination by absorbance measurement at 263 nm. The method was linear in the range of 200-1600 ng/spot, average recovery was 101 %. The analytical results obtained by HPTLC were comparable with the HPLC method of USP XXIII. The HPTLC method was suggested as alternative to the USP method considering the high throughput.

J. Chromatogr. A 1217(8), 1396-1398 (2010). Sparation of enantiomers of atenolol, propranolol, and salbutamol using different loading/impregnation techniques for the Cu(II) complexes of l-proline, l-phenylalanine, l-histidine, N,N-dimethyl-l-phenylalanine, and l-tryptophan. TLC on silica gel with acetonitrile – methanol – 2 mM aqueous solution of Cu(II) 3:4:5. The different techniques were: A) using the Cu(II)-l-amino acid complex as chiral mobile phase additive, B) development of plates in solutions of Cu-complex, and C) with a solution of Cu(II)acetate as mobile phase additive for plates impregnated with the amino acids. Detection of zones by exposure to iodine vapor.