Food Chem. 239, 831-839 (2018). HPTLC of saffron on silica gel with 1-butanol – acetic acid – water 4:1:1. Qualitative identification at UV 254 nm. The hRf values of the nine detected zones (crocins and picrocrocin derivatives) were 19, 29, 43, 56, 63, 67, 80, 85, and 96. Captured images were imported to the MATLAB program for pattern recognition and discrimination between different saffron samples on the basis of their soil electro-conductivity values as indicator of soil salinity. The data pre-processing included elimination of chromatographic artifacts such as baseline drifts and spot misalignment.

J. Planar Chromatogr. 30, 333-339 (2017). Review of applications of chiral TLC to demonstrate the dynamic phenomenon of the spontaneous oscillatory chiral conversion with the low molecular weight carboxylic acid. The principles of oscillatory processes and chiral conversion and condensation, as well as selected examples of the applicability of chiral TLC to dynamic studies were reviewed.

J. Chromatogr. A 1529, 93-106 (2017). Presentation of the quantitative effect-directed profiles of 77 industrially and freshly extracted botanicals like herbs, spices, vegetables and fruits, widely used as food ingredients, dietary supplements or traditional medicine for their quality assessment with regard to potential health-promoting activities. Fast assignment of single active compounds and evaluation of their contribution to the overall activity, originating from a food or botanical sample by combination of HPTLC hyphenated with UV/Vis/FLD detection and effect-directed analysis, using the 2,2-diphenyl-1-picrylhydrazyl radical, Gram-negative Aliivibrio fischeri, Gram-positive Bacillus subtilis, acetylcholinesterase and tyrosinase assays. Characterization of bioactive compounds of interest eluted using an elution head-based interface by HPTLC-UV/Vis/FLD-EDA-ESI-(HR)MS method. Demonstration of the excellent quantification power of the method by applying for rosmarinic acid, contents ranged from 4.5 mg/g (rooibos) to 32.6 mg/g (rosemary), for kaempferol-3-glucoside from 0.6 mg/g (caraway) to 4.4 mg/g (wine leaves), and for quercetin-3-glucoside from 1.1 mg/g (hawthorn leaves) to 17.7 mg/g (thyme). The mean repeatabilities (%RSD, n=18) were ≤ 2.2 % for the three compounds and the mean intermediate precision (%RSD, n=3) was 5.2 % over three different days.

Food Chem. 239, 1182-1191 (2018). HPTLC of coumarin in 43 commercially available cinnamons and cinnamon containing foods on silica gel with n-hexane – ethyl acetate – ammonia 76:26:1. Detection by dipping into a 10 % ethanolic potassium hydroxide solution, followed by drying, and dipping into a 10 % methanolic PEG 400 solution for stabilization of the fluorescence. Quantitative determination by fluorescence measurement at 366/>400 nm. The contents ranged from 0.3 to 5129 mg/kg with mean intermediate precisions of 4 %. The hRF value for coumarin was 50. LOD and LOQ were 200 and 400 pg/zone, respectively. Confirmation of preliminarily assigned coumarin zones was performed with a single quadrupol MS and HRMS. Effect-directed detection was also performed and coumarin was active against A. fischeri bacteria down to 100 ng/band.

J. Planar Chromatogr. 30, 423-426 (2017). 2D-HPTLC of phytoestrogenic active compounds in the root of Glycyrrhiza glabra on RP-18 with hexane – ethyl acetate – acetone 9:3:2 in the first direction and acetone – water 3:2 in the second direction. Effect-direct analysis by dipping into a yeast suspension followed by incubation at 30 °C for 4 h, drying at 37 °C for 15 min and spraying with the combined reaction buffer C (20 mL reaction buffer C is mixed with 0.2 mL of a freshly prepared solution of 0.05 g/mL 4-methylumbelliferyl-ß-D-galactopyranoside in DMSO or 0.2 mL of a freshly prepared solution of 0.05 g/mL 5-bromo-4-chloro-3-indoxyl-ß-D-galactopyranoside (X-Gal) in DMSO). Fluorescence detection at UV 366 nm._x000D_

J. Planar Chromatogr. 30, 474-480 (2017). HPTLC of phenol (1), pyrocatechol (2), hydroquinone (3) and trihydroquinone (4) in urine samples on silica gel with hexane – dioxane – ethyl acetate 7:1:2. Detection by spraying with Folin‒Ciocalteau phenol reagent – water 1:2. Visible blue color zones of the four phenolic benzene metabolites were punched 2 cm in diameter individually using a paper punching machine, and collected in test tubes containing 1 mL of distilled water. To 10 μL of Folin–Ciocalteu reagent in each tube 60 μL of 20 % sodium carbonate solution were added. Quantitative determination by absorbance measurement at 765 nm. The hRF values for (1) to (4) were 69, 40, 28 and 9, respectively. Linearity was between 0.25 and 1.5 mg/mL for (1) to (4). LOD and LOQ were 9 and 3 μg/mL for (1), 30 and 90 μg/mL for (2), 6 and 18 μg/mL for (3), and 7 and 21 μg/mL for (4). The intermediate/interday/intra-day precisions were below 4 % (n=5). Average recovery was between 92 and 98 %.

A review. Food Chem. 254, 377-389 (2018). Review of extraction and purification methods for Lycium barbarum polysaccharides, including chemical characterization and evaluation of hypoglycaemic and hypolipidaemic effects. HPTLC methods were described to determine monosaccharide composition and map the glycidic component of glycoconjugates.

J. Planar Chromatogr. 31, 230-234 (2018). HPTLC of hypoxoside in the roots of Hypoxis hemerocallidea on silica gel with chloroform – methanol – water 35:15:1. Quantitative determination by absorbance measurement at 257 nm. The hRf value for hypoxoside was 30. Linearity was in the range of 0.02-1.80 µg/mL. The LOD and LOQ for hypoxoside were 0.51 µg and 1.65 µg/mL. (Note by the editor: It can not be true that the start of calibration is below the LOD by a factor of 25.) The intermediate precision was below 5 %. Average recovery was 84 %.