J. Planar Chromatogr. 30, 405-410 (2017). HPTLC of 200 hydrocarbons containing condensed aromatic rings on silica gel with n-hexane and n-heptane. A magnetic field at constant inductivity (0.44 T), generated by a pair of permanent magnets perpendicular to the direction of chromatogram development was used to investigate its influence in the retention of substances.

(Xi Xian) by a validated high-performance thin-layer chromatographic method. J. Planar Chromatogr. 30, 516-520 (2017). HPTLC of chlorogenic acid (1) and caffeic acid (2) in the leaves of Siegesbeckia orientalis on silica gel with toluene ‒ ethyl acetate ‒ formic acid ‒ methanol 30:30:8:3. Quantitative determination by absorbance measurement at 366 nm. The hRF values for (1) and (2) were 19 and 83, respectively. Linearity was between 200 and 600 ng for (1) and (2). LOD and LOQ were 20 and 40 ng/zone for (1) and 59 and 120 ng/zone for (2), respectively. The intermediate/interday/intra-day precisions were below 3 % (n=3). Recovery was 99.0 %.

CBS 119 (2017 12-13. HPTLC of hop extracts on silica gel (MS-grade) by automated multiple development using a 9-step AMD 2 gradient based on ethyl acetate – methanol – n-heptane. Quantitative determination by fluorescence measurement at 360/>400 nm with the deuterium lamp. The hRF of α-acids was 36 and of β-acids 65 and the matrix was well separated. With this study the differences in the bitter acid content of regional and varietal hops was determined. In most cases, the bitter hops contained more bitter acids than aromatic hops.

J. Planar Chromatogr. 31, 57-60 (2018). HPTLC of azathioprine, caffeine, theobromine, theophylline and acyclovir on RP-18 W with acetonitrile - TRIS–HCl buffer pH 8.0 (1 mM) 1:4. It was neither possible to separate azathioprine from caffeine, nor theobromine from theophylline. Under the same conditions, pressurized planar electrochromatography with a polarization voltage of 2.5 kV showed better results, as all five purine derivatives could be separated. Detection under UV 280 nm._x000D_

J. Planar Chromatogr. 31, 213-219 (2018). HPTLC of β-sitosterol in the leaves of five Ficus species (F. carica, F. nitida, F. ingens, F. palmata, and F. vasta) on silica gel with ethyl – acetate 4:1. Detection by spraying with p-anisaldehyde reagent followed by drying. Quantitative determination by absorbance measurement at 550 nm. The hRf value for β-sitosterol was 17. Linearity was in the range of 100-1400 ng/zone. The intermediate precision was below 2 % (n=6). The LOD and LOQ were 32 and 98 ng/zone, respectively. Recovery was between 98.5 and 99.7 %.

Food Control 90, 48-57 (2018). HPTLC of saffron and its main adulterants (sumac, turmeric, safflower, common madder, quinoline yellow, sunset yellow and tartrazine) on silica gel with 1-butanol – acetic acid – water 4:1:1. Images were captured under visible light and subjected to MATLAB software. The method included image preprocessing capable of identifying such adulteration based on modelling that includes principal component analysis, k-means and chemometric methods such as partial least squares discrimination analysis, variable selection (loading weight and variable importance in projection) and linear discriminant analysis.

in different_x000D_ growth stages by thin-layer chromatographic scanning. J. Planar Chromatogr. 31, 190-196 (2018). HPTLC of rupestonic acid (1), vitexicarpin (2), apigenin (3), and luteolin (4) in Artemisia rupestris on silica gel with chloroform – methanol – formic acid – water 650:63:17:7. Quantitative determination by absorbance measurement at 250 nm for (1) and 352 nm for (2) to (4). The hRf values for (1) to (4) were 56, 67, 34 and 18, respectively. Linearity was in the range of 128-725 ng/zone for (1), 70-400 ng/zone for (2), 26-145 ng/zone for (3) and 17-97 ng/zone for (4). The intermediate precision was below 5 % (n=6). Average recoveries for (1) to (4) were 100.0 %, 103.6 %, 98.1 % and 99.9 %.

Microbiol. Res. 207, 177-187 (2018). TLC was applied to characterize the inhibition of polyamine_x000D_ on the ATPase activity of PotA on cellulose with a buffer solution containing 1 M lithium chloride and 0.5 M formic acid in water. Labeled [α-32P]-ADP was quantified using a phosphor imaging analysis system.