Acta Chromatographica 20(4), 685-695 (2008). Determination of p-coumaric and protocatechuic acids in an ether fraction from a methanolic extract of Aquilegia vulgaris L. by HPTLC on silica gel with mixtures of heptane, dichloromethane, diisopropyl ether, formic acid, and water in various ratios. Satisfactory separation of the phenolic acids was achieved by use of the multiple gradient development technique. HPTLC results of the quantities of p-coumaric and protocatechuic acids were somewhat higher (0.396 and 2.584 mg/g dry plant material, respectively), than those determined by HPLC (0.374 and 2.283 mg/g dry plant material, respectively). Both methods were satisfactory in the precision, expressed as relative standard deviation, and are useful for quality control of Aquilegia vulgaris extracts.

62nd Indian Pharmaceutical Congress Abstract No. F-384 (2010). TLC of isotretinoin on silica gel with toluene – ethyl acetate 4:1. The hRf value was 54. Quantitative determination by absorbance measurement at 345 nm. The method was linear in the range of 20-100 ng/band. The sample was analysed by RP-HPLC and the result was comparable with the TLC method.

62nd Indian Pharmaceutical Congress Abstract No. F-13 (2010). HPTLC of risperidone in bulk and pharmaceutical dosage form on silica gel with dichloromethane – methanol – ethanol – triethylamine 120:120:60:1. Quantitative determination by absorbance measurement at 280 nm. The linearity was obtained in the range 4-8 µg/spot (r2 =0.9989). The limit of detection and the limit of quantification for risperidone were 98 ng/zone and 599 ng/zone, respectively. The recovery was 99.5 %.

Acta Chromatographica 20(4), 637-642 (2008). Specific separation of thiamine hydrochloride from riboflavin, nicotinic acid, calcium D-pantothenate, pyridoxine hydrochloride, cyanocobalamin, and ascorbic acid by TLC on silica gel with dioxane – water 1:1. Detection under UV light. Examination of the effect of impurities (metal cations and inorganic anions) on the chromatography of thiamine hydrochloride. The detection limit for thiamine hydrochloride was 0.09 µg/zone and the relative standard deviation of the hRf value of thiamine hydrochloride in five analyses was 14.9 %.

J. Pharm. Biomed. Anal. 53, 911-918 (2010). Comparative study on several approaches of TLC lipophilicity determination with the goal of standardization: single TLC runs, extrapolation of retention, principal component analysis of a retention matrix, PARAFAC on a three-way array and a PLS regression. All techniques were applied to 35 simple model solutes (e.g. benzoic acid, caffeine, benzocaine, isoniazide) using nine concentrations of six modifiers (acetonitrile, acetone, dioxane, propan-2-ol, methanol and tetrahydrofurane). Methanol and dioxane were most suitable as modifiers, while acetonitrile provided no suitable correlation of retention with lipophilicity. The approach of single TLC runs provided surprisingly good results. The chemometric processing methods (PCA, PARAFAC and PLS) did not show any advantage compared to classical methods. There is a need to use robust regression and correlation measures due to presence of significant outliers.

J. Strait Pharm. 22(11), 90-92 (2010). TLC of components of Yinhu granules: 1) for Artemisia capillaris Thunb. on polyamide phase with acetic acid; 2) for Radix Notoginseng on silica gel with chloroform – methanol – water 13:7:2. Detection 1) under UV 366 nm; 2) by spraying with 10 % sulfuric acid in ethanol and heating at 105 ºC until the zones were visualized.

Rapid Commun. Mass Spectrom. 25, 2619–2626 (2011). HPTLC of cardiolipins in hepatocyte sample on silica gel with chloroform - ethanol - water - triethanolamine 30:35:7:35. Qualitative determination by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Caution is required if cardiolipin is analyzed directly from the total lipid extract because phospholipid dimers may be interpreted as cardiolipins.

J. Liq. Chromatogr. Relat. Technol. 34, 1502-1517 (2011). HPTLC of glycyrrhizic acid in bulk drug and pharmaceutical formulations on silica gel with butanol - glacial acetic acid - water 7:1:2. Quantitative determination by absorbance measurement at 254 nm. The hRf of glycyrrhizin was 24. Linearity was 200-1000 ng/zone. Limits of detection and quantification were found to be 80 and 200 ng/band. The intermediate/inter-day/intra-day precision was below 0.6 % (n=3). Recoveries (by standard addition) were 98.1-99.5 %.