J. Planar Chromatogr. 24, 66-71 (2011). HPTLC of extracts of Stresroak premix and gallic acid (1), mangiferin (2), and withanolide A (3) as standards on silica gel with A) ethyl acetate - formic acid - acetic acid - water 100:11:11:27, for (1) and (2), and B) chloroform - methanol 9:1 for (2) in a twin trough chamber. Quantitative determination by absorbance measurement at 280 nm for (1), 330 nm for (2), and 225 nm for (3). The hRf values of (1), (2) and (3) were 76, 29, and 48, respectively. The average recoveries were 100.4 % (1), 99.3 % (2) and 98.0 % (3). The linear concentration range was 50-150 ppm for (1), and 40-100 ppm for (2) and (3). The LOD, defined as the amount of compound required to produce a signal at least three times the noise level, for gallic acid, mangiferin, and withanolide A was 80, 110, and 200 ng for (1), (2), and (3), respectively. The LOQ was 20, 27, and 38 µg, respectively.

J. of Chromatogr. Sci. 49, 560-567 (2011). Evaluation of the fingerprinting efficiency of a novel two-dimensional analytical system composed of RP-TLC and RP-LC-MS. The efficiency of the system was compared with that of the one-dimensional system RP-TLC with MS detection. The test samples were phenolic acid extracts from Salvia lavandulifolia. Both systems can be applied to the fingerprint analysis of herbal extracts, but the two-dimensional system based on RP-TLC and RP-LC-MS can provide more abundant information.

J. Planar Chromatogr. 24, 166-171 (2011). HPTLC of brimonidine tartrate as the bulk drug and in formulations on silica gel with methanol - toluene - triethylamine 10:35:2. The hRf value was 48. Quantitative determination by densitometry in absorbance mode at 247 nm. Linearity was between 100 and 600 ng/band (r² = 0.9965). LOD and LOQ were 9 and 28 ng/band, respectively. The intra-day and inter-day precision (%RSD, n = 3) was 1.1-1.2 % and 0.5-1.0 %, respectively. Recovery was between 98.7-100.4 %. The repeatability of application (%RSD, n = 6), was 1.6 %.

J. Planar Chromatogr. 24, 48-52 (2011). HPTLC of hydroquinone on silica gel with chloroform - methanol 17:3 in a twin-trough chamber after saturation for 30 min at 25 °C. Quantitative determination by densitometry in absorbance mode at 289 nm. The hRf of hydroquinone was 51. Linearity was between 100 and 2500 ng/zone. Mean recovery was 99.2 %, with %RSD between 1.7-2.0 %. The intra-day precision (n = 3) as %RSD was 0.9-1.1 % and the inter-day precision 1.0-1.2 %. The LOD and LOQ was 39 and 116 ng/band, respectively.

J. Strait Pharm. 22 (12), 59-60 (2010). TLC of the extracts of the title traditional Chinese medicine 1) for red Ginseng, on silica gel with benzene - ethyl acetate - formic acid 20:16:3, detection by spraying with 3 % FeCl3 in ethanol and viewing under daylight; 2) for Chinese Taxillus twig, on silica gel with water-saturated toluene - ethyl acetate - formic acid 5:4:1, detection by spraying with 5 % AlCl3 in ethanol; 3) for Hawthorn, on silica gel with toluene - ethyl acetate - glacial acetic acid 24:8:1, detection by spraying with 3-10 % sulfuric acid in ethanol and heating at 105 °C until the zones were detected; 4) for Alisma orientale, on silica gel with toluene - ethyl acetate - formic acid 14:7:2, detection by spraying with acetic acid - concentrated sulfuric acid - ethanol 1:1:1, heating at 105 °C until the zones were detected and viewing under daylight. Identification by comparison with the standards of the individual drug.

J. Planar Chromatogr. 24, 312-315 (2011) HPTLC of methanolic extracts of L. tibetica on silica gel (prewashed with methanol) with hexane - ethyl acetate - formic acid 12:7:1 for three furofuranolignans (sylvatesmin, (+)-piperrtol, horsfieldin), beta-sitosterol, and oleanolic acid, and with chloroform - methanol - water - formic acid 70:25:4:2 for four furofuranolignans (phillyrin, tibeticoside A, lantibeside C, and lantibeside), verbascoside and isoverbascoside in a twin-trough chamber with saturation for 20 min. Detection by immersion in ethanolic sulfuric acid for 2 s followed by heating for 5 min at 100 °C. The hRf values were 17, 25, 29, 51, 60, 70, 66, 49, 46, 19, and 21 for sylvatesmin, (+)-piperrtol, horsfieldin, oleanolic acid, beta-sitosterol, phyllirin, tibeticoside A, lantibeside C, lantiboside, verbascoside and isoverbascoside, respectively.

Part III – a study on CN adsorbent layers. J. Planar Chromatogr. 25, 471-474 (2012). TLC of 35 simple compounds with known literature lipophilicity on cyano phase with increasing mixtures of methanol - water. Detection by absorbance measurement at 254 nm. Correlation between single RM values and lipophilicity values as well as dependences between the extrapolated log kW and experimental lipophilicity was described.

J. of Chromatogr. A 1248, 169-177 (2012). Purified oligomers of hyalobiuronic acid are indispensable tools to elucidate the physiological and pathophysiological role of hyaluronan degradation by various hyaluronidase isoenzymes. Establishment and validation of a novel sensitive, convenient, rapid, and cost-effective HPTLC method for the qualitative and quantitative analysis of small saturated hyaluronan oligosaccharides consisting of 2–4 hyalobiuronic acid moieties. HPTLC on amino phase with 1-butanol - formic acid - water 3:5:2 or 3:4:1. Detection 1) by spraying with orcinol in various concentrations of sulfuric acid; 2) by dipping into the reagent of orcinol in 10 % sulfuric acid and Morgan–Elson reagent; 3) by illuminating with white light and UV 366 nm after heating. The simple reagent-free in situ derivatization of 3) resulted in a detection limit of 7–19 pmol/band and LOQ of 37–71 pmol/band depending on the analyzed saturated oligosaccharide. Identification of the analytes by TLC-ESI-MS. The validated HPTLC method, as an alternative to sequential techniques such as HPLC and CE, can easily be automated and is applicable to the analysis of multiple samples in parallel.