Chromatogr. Res. Int. 10, 1-11 (2014). HPTLC of artemisinin of Indian Artemisia annua L. was performed on HPTLC foil silica gel with n-hexane - ethyl acetate 3:1 in a twin-trough chamber up to a migration distance of 85 mm. Detection with anisaldehyde sulphuric acid reagent followed by heating at 110 °C for 10–15 min. Quantitative determination of artemisinin by densitometry at 540 nm. The hRf value of artemisinin (pink colored) was 28. The linearity was between 400 to 2800 ng/spot with a correlation coefficient of 0.9975. The precision (%RSD) was ≤3.3% (n=3). The LOD and LOQ were 40 ng/zone and 80 ng/zone, respectively. Recoveries were between 74 and 105 % for 0.6 mg/mL. Artemisinin content was highest in the leaf extract; no artemisinin was detected in the root extract.

J. of Chromatogr. Sci. 53 (2), 338-344 (2014). Presentation of a method for the simultaneous quantification of three glycosidic isoflavones (daidzin, genistin and glycitin) in soybean (Glycine max L.) by HPTLC on silica gel with toluene – ethyl acetate – formic acid – acetic acid 2:16:2:1. The hRf values of daidzin (1), genistin (2) and glycitin (3) were 39, 51 and 32, respectively. Detection and quantification by densitometry at 260 nm. Validation in accordance with the ICH guidelines with the results for precision of ≤2.1 %, ≤0.7 % and ≤0.1 %, recovery of 95.9-106.7 %, 86.9-106.6 % and 98.5-105.6 %, LOD of 3, 19 and 4 µg/mL and LOQ of 9, 59 and 11 µg/mL for the glycosidic forms of (1), (2), and (3). The method was used for the analysis of the soybean variety Kh-09 bragg which showed high amounts of glycosidic isoflavones: 278, 598 and 109 µg/g for (1), (2), and (3). After fermentation with Bacillus subtilis, the concentration of glycosidic isoflavones significantly decreased while those of the aglycone isoflavones increased.

root extract via HPTLC–UV/Vis/FLD–EDA–MS. J. Planar Chromatogr. 31, 79-86 (2018). HPTLC with effect-directed analysis (EDA) for (bio)profiling of Pimpinella saxifraga root. HPTLC on silica gel with 1) ethyl acetate – methanol – acetic acid 8:3:1 for polar separation, and 2) toluene – ethyl acetate – acetic acid 20:5:1 for apolar separation. Ten different detections were shown on one HPTLC plate cut into sections. Detection of absorbing compounds under A) white light and B) UV 254 nm and C) fluorescent ones under UV 366 nm. Three plate sections were used for microchemical derivatizations for D) detection of flavonoids after derivatization with diphenylborinic acid 2-aminoethylester reagent, followed by dipping into a polyethylene glycol 400 solution, E) universal detection with anisaldehyde sulfuric acid reagent, and F) detection of glycosides with diphenylamine aniline reagent. Effect-directed detection of G) DPPH scavenging compounds, antimicrobials via H) A. fischeri and I) B. subtilis bioassays, and J) AChE inhibitory compounds was also performed. Multi-detection showed multi-potent zones with hRF values of 19, 24, 49 and 78, which were exemplarily further characterized by HPTLC–ESI–MS in both ionization modes. A weak estrogen-effective zone was also observed via HPTLC–planar yeast estrogen screen (pYES) bioassay on RP-18 with n-hexane – toluene – ethyl acetate 6:3:4 or, after optimization, toluene – ethyl acetate 1:1.

J. Sep. Sci. 1-9 (2017). HPTLC of canagliflozin (1) and its degradation product (2) on silica gel with acetone – ethanol 4:1. Quantitative determination by absorbance measurement at 290 nm. The hRF values for (1) and (2) were 64 and 81, respectively. Linearity was between 0.4 and 3.6 μg/zone for (1) and 0.2 and 3.2 μg/zone for (2). LOD and LOQ were 70 and 200 ng/zone for (2). The intermediate/interday/intra-day precisions were below 2 %. Average recovery was 100.7 % for (1) and 99.4 % for (2).

J. Chromatogr. Sci. 56, 518-523 (2018). Presentation of a validated method for the quantitation of dihydrokaempferol-4′-O-glucopyranoside. This flavanonol glucoside is a marker compound in the flower of Alcea rosea L. with significant antioxidant and anticancer activity against the HepG-2 cell line. HPTLC on silica gel with ethyl acetate – methanol – water – acetic acid 600:100:80:3 over 70 mm with chamber saturation for 30 min. Quantitative determination by absorbance measurement at 295 nm. The amount of dihydrokaempferol-4′-O-glucopyranoside in the flowers of A. rosea was 0.733 g/100 g and 0.928 g/100 g after maceration and sonication for 15 min, respectively. Linearity was in the concentration range of 0.9-3.6 µg/zone. The %RSD of the intra-day and inter-day precision was 0.2–1.5 % and 0.5–1.7 %, respectively. The LOD and LOQ were 312 ng/zone and 947 ng/zone, respectively.

Effect of nitrogen nutrition. Proc. Intern. Symposium on TLC with special emphasis on OPLC, Szeged, 75-76 (1984). OPLC (OPTLC) of proline, hydroxyproline, glutamine, asparagine on silica with 10 different buffer solutions. Detection with ninhydrin in methanol - acetic acid and heating at 105 °C for 10 minutes. Quantitative determination by densitometry.

J.A.O.A.C. 67, 973-975 (1984). TLC of aflatoxins B1, B2, G1, G2 on silica with chloroform - acetone 9:1. Detection by UV 366 nm. Quantification by fluorodensitometric measurement. Detection limit: 2ng/g.

Proc. of Euro Food Chem. III, 2, 216-223, March 1985, Antwerp, Belgium. Consecutive extraction with sodium carbonate and ether; TLC on silica with benzene; in-situ derivatization with p-bromophenacylbromide; densitometric scanning by absorbance; detection limit 50 ng; good precision.