J. Liq. Chromatogr. Relat. Technol. 37, 1416-1426 (2014). HPTLC of lumefantrine (1) and artemether (2) on silica gel with toluene – ethyl acetate – acetic acid 4:15:5. Detection by dipping into a derivatization reagent (10 % each of methanolic concentrated sulfuric acid and anisaldehyde), followed by heating at 110 °C for 3 min. Quantitative determination by absorbance measurement at 519 nm. The hRF values for (1) and (2) were 55 and 70, respectively. Linearity was in the range of 60-360 ng/zone for (1) and 10-60 ng/zone for (2). The intermediate/interday/intra-day precisions were below 1 % (n=3). The LOD and LOQ were 7 and 26 ng/zone for (1) and 2 and 6 ng/zone for (2), respectively. Recoveries were between 97.6-101.3 % for both (1) and (2).

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).

CBS 120, 5-7 (2018). HPTLC of extracts of broad-leaved dock (Rumex obtusifolius) on silica gel with toluene – ethyl acetate – formic acid 1:8:1 over 75 mm. Detection by 3-step derivatization using automated spraying: 1) natural product reagent (NP), 2) NP in combination with polyethylene glycol solution (PEG), 3) vanillin-sulfuric acid reagent followed by heating at 100 °C for 3 min. To derivatize areas of the same plate with different reagents, the areas, which were to be evaluated underivatized by TLC-MS, were covered with a suitable segment of a used HPTLC plate, the layer turned upwards. Evaluation under UV 254 and 366 nm, white light, and by densitometry in absorbance measurement at 280 nm. Direct elution of target zones into a triple quadrupole mass spectrometer with electrospray ionization and recording in the negative ionization mode allowed a quick and easy screening of constituents. Overall, many flavan-3-ols, procyanidins, anthraquinones and naphthyl glycosides were detected in Rumex obtusifolius. The stilbenes frequently found in other Polygonaceae (Rheum spec.) were present only in small quantities.

Proc. Intern. Symposium on TLC with special Emphasis on OPLC, Szeged, 67, (1984). OPLC (OPTLC) of amino acids on silica with 1) butanol - acetic acid - water 4:1:1, 2) phenol -1 % SDS - isobutanol - propanol - butanol - acetic acid 70:28:2:2:2:1.7. Detection with ninhydrin + Cu or Cd acetate reagent. Detection with videodensitometer, coefficient of variation 6 %.

J. Chromatogr. 295, 141-151 (1984). TLC of various primycin preparations on silica with chloroform - methanol - acetone - water 28:42:14:16, chloroform - methanol - water 45:45:10, chloroform - methanol - formic acid - water 50:35:14:1, propanol - acetic acid - water 7:1:2 and other solvent systems. Detection with vanillin/sulfuric acid. Densitometry after detection at 590 nm. Also two-dimensional TLC using numerous solvent systems and PLC.