Acta Chromatographica 22 (4), 651-663 (2010). HPTLC of wedelolactone (WED) and asiaticoside (ASI) in Eclipta alba and Centella asiatica Linn., respectively, on silica gel with toluene - acetone - methanol - formic acid 60:40:40:1. The hRf value was 26 and 75 for ASI and WED, respectively. Detection by spraying with 10 % methanolic sulphuric acid. Quantitative evaluation by absorbance measurement at 317 nm for WED and at 530 nm after derivatization for ASI. The linearity was in the range of 50-250 ng/band for WED and 150-550 ng/band for ASI with r = 0.999 for WED and 0.9989 for ASI. The recovery of WED was 99.3 % and of ASI 99.5 %.

J. of Chromatogr. A 1218 (33), 5693-5704 (2011) A micro-TLC platform for the fast analysis of low-molecular mass compounds from spirulina samples was developed. The target compounds were extracted with methanol, acetone or tetrahydrofuran. HPTLC on RP-18W with acetone - n-hexane 3:7 in an unsaturated chamber using a temperature controlled micro-planar chromatographic device based on a horizontal chamber. Detection under visible light before and after exposure to iodine vapor. Pictures of the chromatograms were acquired with an office scanner and digitalized. The quantitative data was analyzed using cluster analysis and principal components analysis. With this method it was possible to distinguish genuine spirulina and non-spirulina samples as well as fresh and expired commercial products.

J. Planar Chromatogr. 23, 365-368 (2010). HPTLC of palmitoyl hexapeptide (an antiwrinkle peptide) on silica gel with toluene - ethanol 9:1 in a twin-trough chamber with saturation for 30 min at room temperature (25 +/- 2 °C). The hRf was 33. Quantitative determination by absorbance measurement at 211 nm. Linearity was between 10 and 30 ng/band. The LOD and LOQ was 3 and 9 ng/band, respectively. The intra-day precision (%RSD, n = 6) was 0.9-1.5 % and the inter-day precision 0.9-1.4 %. The small %RSD obtained after small changes of the method conditions indicate the method is robust. The recovery of the method was in the range of 98.9-101.3 %.

J. AOAC Int. 94, 795-802 (2011). HPTLC of boeravinone B and E on silica gel (prewashed with methanol) with toluene - ethyl acetate - acetonitrile - formic acid 60:12:4:3 in a twin-trough chamber after saturation for 10 min at 25 +/- 1 °C at a relative humidity of 35-40 %. Quantitative determination by absorbance measurement at 275 nm. The hRf value of boeravinone B and E was 47 and 31, respectively.The intra-day and inter-day precision (n = 3) were 0.6-1.7 % and 1.0-1.3 % for boeravinone B and 0.3-1.5 % and 1.3-1.5 % for boeravinone E. The repeatability of application and detection (%RSD) was between 0.8-1.1 % for boeravinone B and 0.3-0.9 % for boeravinone E (n=7). Linearity was between 75-360 ng/zone for boeravinone B and 160-768 ng/zone for boeravinone E. The LOD and LOQ were 9 and 13 ng/zone for boeravinone B and 30 and 42 ng/zone for boeravinone E. %RSD of robustness was <2 %. The recovery was 98.9-99.5 % for boeravinone B and 97.9-98.4 % for boeravinone E.

Planta Med. 77, 548 (2011). HPTLC of glabridin (4-[(3R)-8,8-dimethyl-3,4-dihydro-2H-pyrano[6,5-f]chromen-3-yl]benzene-1,3-diol) on silica gel with toluene - dichloromethane - ethyl acetate 1:1:1. Detection under UV light at 286 nm.

J. Liq. Chromatogr. Relat. Technol. 32, 2437-2450 (2009). HPTLC calliterpenone (1) and calliterpenone monoacetate (2) in the leaves of Callicarpa macrophylla on silica gel with methanol - water 9:11. Quantitative determination by absorbance measurement at 210 nm. The hRf values of (1) and (2) were 43 and 73, respectively. Linearity was between 1-5 µg/zone for (1) and (2). LOD and LOQ were 230 and 780 ng/zone for (1) and 220 and 730 ng/zone for (2). Intra-day and inter-day precisions ranged between 1.3-1.7 % for (1) and 1.1-1.7 % for (2). Recoveries (by standard addition) were between 97.5-100.8 % for both.

J. Planar Chromatogr. 25, 548-553 (2012). New modified stationary phases obtained by chemical modification of diatomaceous earth from Filia and silica gel with trimethoxyethylphenylsilane. Separations on ethyl-phenylmodified adsorbents are similar to the separation on C8.

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.