J Chromatogr Sci, 60 (4), 372-386 (2022). Investigation of the dual retention mechanism in TLC taking place on three stationary phases of different polarity (C-18, silica gel and DIOL)  using binary mobile phases composed of acetonitrile as the main component and water, or methanol as a modifier. The test analytes were 12 compounds of pharmaceutical importance and considerably different chemical structure, i.e. the imidazoline and serotonin receptor ligands, and their related compounds. Determination of retention of each analyte in each investigated chromatographic system in a wide enough range of the mobile phase composition, with volume fraction of the mobile phase modifier ranging from 0.10 to 0.90. Calculation of the exact turning point values as a proof of occurrence of the reversed-phase hydrophilic interaction chromatography (HILIC/RP) retention mechanism based on the multimodal retention model. Analysis of the dual retention mode with the use of the volume fraction of the mobile phase modifier, the total polarity and the total solubility models, allowing the dual (HILIC/RP) retention mechanism for the DIOL, C-18 and silica gel stationary phase to be confirmed. The observed retention mechanism was more complicated than the dual HILIC/RP one in the case of the DIOL stationary phase and acetonitrile/methanol mobile phase.

J. Planar Chromatogr. 35, 251-263 (2022). HPTLC of ten imidazoline and serotonin
receptor ligands on amino phase with acetonitrile modified with different volume fractions of methanol and water as mobile phases, acidified with 20 mM ammonium acetate and 0.1 % acetic acid. Detection under UV light at 254 nm. Correlation between retention descriptors and molecular properties was analyzed and different elution orders and separation performances were obtained for the compounds, depending on the chromatographic system employed. 
 

J. Planar Chromatogr. 35, 331-337 (2022). HPTLC of selected varieties of hop cultivars H. lupulus on silica gel with 8 % isopropanol in dichloromethane. Detection under UV light at 254 and 366 nm. Direct bioautography by dipping into Bacillus subtilis bacterial suspension for 10 s, followed by incubation at 37 °C for 17 h. TLC plates were covered with 0.2 % aqueous MTT tetrazolium dye solution (thiazolyl blue tetrazolium bromide, 98 %), followed by incubation at 37 °C for 30 min. 
 

J. Planar Chromatogr. 35, 287-297 (2022). HPTLC of species of the grass family (Poaceae), coming from genera: Agrostis, Alopecurus, Anthoxanthum, Apera, Arrhenatherum, Avena, Brachypodium, Briza, Bromus, Calamagrostis, Corynephorus, Cynosurus, Dactylis, Danthonia, Deschampsia, Digitaria, Echinochloa, Elymus, Eragrostis, Festuca, Glyceria, Helictotrichon, Hierochloe, Holcus, Hordeum, Koeleria, Leymus, Lolium, Milium, Molinia, Nardus, Panicum, Phalaris, Phleum, Phragmites, Poa, Saccharum and Setaria on silica gel with ethyl acetate - methanol - water 4:1:1. Detection under UV light at 210, 254, 312 and 366 nm and in fluorescence mode with 312/370, 366/420 and 366/550 nm of excitation and emission filter, respectively. Principal component analysis (PCA) allowed the identifiation of six orthogonal trends in phytochemical composition. 
 

J. Planar Chromatogr. 35, 339-344 (2022). HPTLC of four goldenrod Solidago species (S. gigantea, S. canadensis, S. virgaurea and S. gramnifolia) on silica gel with n-hexane - isopropyl acetate - acetone 16:3:1. Detection by dipping into the cell suspension of the bioluminescent A. fischeri, followed by recording with 50 s exposure time. Further analysis was performed using high-resolution mass spectrometry. Main bioactive markers of the species were Z,Z-matricaria ester from S. virgaurea, solidagenone from S. canadensis, solidagoic acid A, and a dialdehyde clerodane diterpene from S. gigantea, and Z-dehydromatricaria ester from S. graminifolia. 

J. Planar Chromatogr. 35, 265-272 (2022). HPTLC of newly synthesized azaisocytosine-containing congeners on RP-CN with buffered (pH = 7.4) 0.1 M sodium dodecyl sulphate with 20 % of tetrahydrofuran. Detection under UV light at 254 nm. The micellar chromatographic parameters measured using the TLC technique were proposed as lipophilicity descriptors, and, together with the molecular weight and polarizability, the descriptors were applied in the QSARs methodology to predict the compounds’ blood‒brain distribution. 

J Chromatogr Sci, 60 (4), 364-371 (2022). Borage oil, extracted from Borago officinalis Linn., is a well-known medicinal compound with various benefits. Development of an affordable, simple, reliable, rapid and easily accessible method for the estimation of gamma-linolenic acid (GLA) in borage oil by HPTLC on silica gel with hexane - toluene - glacial acetic acid 3:7:1. The hRf value of GLA was 53 ± 4. Quantiative determination by densitometry at 200 nm with an LOD and LOQ of 221 and 737 ng/band, respectively. The method was validated by investigation for parameters like linearity, accuracy, specificity and precision, and found to be highly sensitive for the estimation of GLA in the herbal oil samples and formulations.

J. Strait Pharm. 33 (1), 63-66 (2021). Xiaoer Yanbian Keli granule is a TCM drug for clearing heat and detoxification, reducing phlegm, benefiting the pharynx, and relieving pain, and is mainly used for the treatment of sore throat and cough. For quality control, TLC of methanol extracts of the drug for (A) Lonicera japonica Thunb., on polyacetamide layer with acetic acid, detection in UV 366 nm, identification by fingerprint comparison; for (B) Belamcanda chinensis (L.) Redouté, TLC on silica gel with dichloromethane - butanone - methanol 3:1:1, detection in UV 254 nm, identification by fingerprint comparison; for (C) Radix Tinosporae, Eustoma grandiflorum (Raf.) Shinners and Scrophularia ningpoensis Hemsl., TLC of samples and standards palmatine chloride, harpagoside and platycodin D, on silica gel with n-butanol - glacial acetic acid - water 7:1:2, detection (1) in UV 366 nm, (2) by spraying with 2 % vanillin sulfuric acid solution and viewing in daylight, (3) by spraying with 2 % vanillin sulfuric acid solution, followed by heating at 105°C and viewing in daylight, identification by fingerprint comparison. The presented method was specific and well repeatable, and reduced the sample amount, simplified the sample processing steps, improved the detection efficiency, and reduced the detection costs.