J. Planar Chromatogr. 35, 593-602 (2022). HPTLC of lactucin (1) and lactucopicrin (2) in the whole herb of Cichorium glandulosum on silica gel with ether - ethyl acetate 1:5. Quantitative determination by absorbance measurement at 256 nm. The hRF values for (1) and (2) were 42 and 65, respectively. Linearity was between 498 and 2988 ng/zone for (1) and 499 and 2994 ng/zone for (2). Intermediate precisions were below 5 % (n=6). Average recovery was 100.0 % for (1) and 99.5 % for (2). 

J. Planar Chromatogr. 35, 627-633 (2022). HPTLC of bromfenac in ophthalmic solution on silica gel with toluene - ethyl acetate - glacial acetic acid 375:175:1. Quantitative determination by absorbance measurement at 274 nm. The hRF values for bromfenac was 28. Linearity was between 60 and 270 ng/zone. Intermediate precisions were below 2 % (n=3). The LOD and LOQ were 7 and 22 ng/zone, respectively. Average recovery was 100.7 %.

J. Planar Chromatogr. 35, 603-608 (2022). HPTLC of berberine (1) and ursolic acid (2) in an Ayurvedic formulation on silica gel with chloroform - acetone - formic acid 12:7:1. Quantitative determination by absorbance measurement at 330 nm. The hRF values for (1) and (2) were 46 and 68, respectively. Linearity was between 200 and 1000 ng/zone for (1) and 500 and 2500 ng/zone for (2). Intermediate precisions were below 2 % (n=9). The LOD and LOQ were 91 and 175 ng/zone for (1) and 153 and 465 ng/zone for (2), respectively. Recovery was in the range of 98 and 102 % for (1) and (2).

J. Planar Chromatogr. 35, 643-646 (2022). HPTLC of amitraz in visceral tissue on silica gel with hexane - acetone 4:1. Detection by spraying with 10 % sodium hydroxide solution, followed by heating at 80 °C for 10 min. The plate was then removed and kept for attaining room temperature, followed by spraying with freshly prepared sodium nitrite (1%) in acidic media. Right after, alkaline solution of curcumin (1% in sodium hydroxide solution) was sprayed. The hRF value for amitraz was 63. 

Phytochem. Rev. doi.org/10.1007/s11101-022-09844-x (2022). The paper discussed a prioritization approach for dereplication that focuses on the most necessary to discover as a tool to deliver experimental real-world results. The principle of planar chromatographic super-hypenations was discussed, including a workflow that combined chemistry and biology to prioritize the compounds in complex samples. The workflow consisted in 1) parallel screening and separation of multiple complex mixtures using imaging HPTLC, 2) planar multiplex bioassay for non-targeted detection of important active compounds, and 3) heart-cut elution of active zones of interest directly out of the bioautogram into orthogonal HPLC-DAD-ESI-HRMS for targeted characterization. The power of planar multiplex bioassays was described for different applications, and chances and limitations for dereplication were also discussed.

J. Chromatogr. A. 1690, 463775 (2023). HPTLC of estrogen-like and antiestrogen-like compounds in 15 rosé, white and red wine samples of different origin on RP-18 with n-hexane - ethyl acetate 4:1. Bioassay by dipping into the yeast cell suspension, followed by incubation at 30 °C for 3 h and drying for 4 min. Detection by dipping into 40 mL MUG substrate solution (16 mg MUG in 1 mL dimethyl sulfoxide and 39 mL citrate buffer) for 5 s, followed by incubation at 37 °C for 1 h and drying for 2 min. Detection at FLD 366 nm/ > 400 nm. The 10D hyphenation NP-HPTLC−UV/Vis/FLD–pYAES−heartcut–RP-HPLC–DAD–HRMS/MS allowed the  detection of estrogens as well as antiestrogens in the matrix-rich wine.

J. Chromatogr. A. 1683, 463522 (2022). HPTLC of powdered root sample of Saussurea costus on silica gel with n-hexane - toluene - tetrahydrofuran 10:1:2. Planar bioluminiscent cytotoxicity assay by dipping into concentrated PBS, followed by removal of excess liquid and adding of human embryonic kidney (HEK) 293T cells expressing ELuc, which uses D-luciferin as the substrate for light emission (cell suspension of 5000 cells/μL). To avoid drying out of the plate, two stripes of paper were added to the side of the chamber, which were wetted with 1.5 mL of bidistilled water. After incubation for 6 h, the HPTLC plate was completely dried under cold air, followed by dipping twice into the respective bioluminescent substrate solution for each cell type. Dose-dependent cytotoxicity activity was calculated for the bioluminescence signal reduction. 

J. Chromatogr. A. 1588, 137-149 (2019). HPTLC of sugars (1), amino acids (2), gluconic acid (3) and glycerol (4) in 20 wine samples on silica gel with i-propanol - n-butanol - boric acid solution (200 mg/10 mL) - acetic acid 14:6:3:1 for (1), 2-butanol - ammonia solution (25 %) - pyridine - water 19:5:17:13 for (2), methanol - water 7:3 for (3) and acetonitrile - boric acid solution (200 mg/10 mL) 4:1 for (4). Detection of (3) by heating at 190 °C for 20 min, followed by densitometric evaluation at 366 nm. Further detection by dipping into: 1) diphenylamine-aniline-phosphoric acid reagent, followed by heating at 120 °C for 10 min; 2) vanillin-sulfuric acid reagent, followed by heating at 135 °C for 20 min; 3) ninhydrin reagent, followed by heating at 110 °C for 5 min; 4) bromophenol blue, followed by heating at 110 °C for 10 min. Derivatized plates were documented in white light and under UV light at 366 nm. Quantification of (4) was performed using a deuterium/tungsten lamp at 380 nm. Micro planar chromatography was performed using a device, where the HPTLC foil was covered by a thick glass plate with a hole in the center, through which the mobile phase was supplied. Further analysis by mass spectrometry.