Planta Med. 84(12-13), 941-946 (2018). The activity-guided fractionation and purification steps (column chromatography and liquid-liquid partitions) of a hydromethanolic extract of Alchemilla vulgaris aerial parts (Rosaceae) were monitored by TLC on silica gel with ethyl acetate – acetic acid – formic acid – water 100:11:11:27. Detection at 254 and 336 nm, and by spraying with anisaldehyde reagent followed by heating. A flavonoid (quercetin-glucuronide) was isolated through this process.

Planta Medica 84(12-13), 902-912 (2018). A dichloromethane extract of Athrixia phyllicoides aerial parts (Asteraceae) was eluted on a silica gel column with different mixtures of ethyl acetate and hexane or methanol. This fractionation was monitored on TLC silica gel layers, using the combinations of the same solvents as mobile phases. Detection by derivatization with Natural Product Reagent and PEG, and visualization at UV 254 nm. This allowed the grouping of the fractions into 13 profiles and the isolation of three hydroxy-methoxyflavones and a coumarate.

Planta Medica 84(11), 813-819 (2018). Fluorinated analogues of epigallocatechin-gallate were purified after synthesis by extraction with ethyl acetate from the synthesis mixtures, followed by column chromatography or (for two pairs of isomers) by preparative TLC. This isolation (as well as monitoring of column elution for the other compounds) was performed by TLC on silica gel with mixtures of n-hexane and (less) ethyl acetate in several concentrations, allowing the separation of diastereoisomers (RF values and yields are given). No derivatisation, visualisation because of fluorescing agent in the layers. Structures were identified by NMR and HR-MS, but apart from the TLC.

J. Liq. Chromatogr. Relat. Technol. 43, 852-862 (2020). HPTLC of diphenylacetamide derivatives on RP-18 with binary mixtures of organic modifier (ethanol, n-propanol, tetrahydrofuran and acetonitrile 36–52 % with 4 % increments). Detection at UV 254 nm. Lipophilicity of examined derivatives was determined. Two multivariate methods, Cluster Analysis, (CA) and Principal Component Analysis, (PCA) were performed to study the compliance of the chromatographic parameters, the standard measure of lipophilicity, the pharmacokinetic predictors and the toxicity parameters of the substances.

J. Planar Chromatogr. 33, 281-291 (2020). HPTLC of Weikangling capsules (a Chinese patent medicine for treating chronic gastritis, containing Paeoniae Radix Alba, Glycyrrhizae Radix et Rhizoma, Bletillae Rhizoma, Notoginseng Radix et Rhizoma, Poria, Corydalis Rhizoma, Sepiae Endoconcha, and Belladonnae Extractum) on silica gel with chloroform - methanol - water 14:5:1. Detection by spraying with 10 % sulfuric acid in alcohol, followed by heating at 105 ºC for 5 min. Qualitative analysis at UV 366 nm.

J. Planar Chromatogr. 33, 523-530 (2020). HPTLC of clonazepam (1), lorazepam (2), alprazolam (3), diazepam (4), furazepam (5), oxazepam (6) and nitrazepam (7) in urine on silica gel with chloroform - glacial acetic acid 9:1. Direct extraction of the substances from the plate into a mass spectrometer. The hRF values for (1) to (7) were 73, 44, 22, 64, 18, 53 and 40, respectively. Linearity was between 0.2 and 0.8 µg/mL. Intermediate precision was below 5 %. LOD was 1 ng/mL for each substance. Average recovery was 67.1 % for (1), 68.9 % for (2), 64.2 % for (3), 73.1 % for (4), 50.7 % for (5), 81.4 % for (6) and 64.4 % for (7).

J. Planar Chromatogr. 33, 501-509 (2020). HPTLC of chloramphenicol (1), dexamethasone sodium phosphate (2) and tetrahydrozoline HCl (3) in the absence or presence of p-nitroacetophenone (4) on silica gel with ethanol - water - ammonia 14:5:1 (method A) and acetonitrile - water - ammonia 20:6:1 (method B). Quantitative determination by absorbance measurement at 242 and 220 nm. The hRF values for (1) to (3) were 76, 65 and 20, respectively, in method A and the hRF values for (1) to (4) were 78, 38, 58 and 87, respectively, in method B. Linearity was 0.1-1.4 µg/zone for (1), 0.2-1.2 µg/zone for (2) and 0.1-0.5 µg/zone for (3) in method A and 0.6-1.8 µg/zone for (1), 0.8-3.2 µg/zone for (2), 0.01-0.1 µg/zone for (3) and 0.3-1.4 µg/zone for (4) in method B. Intermediate precision was below 2 % (n=3). The LOD and LOQ were 30 and 90 ng/zone for (1), 40 and 120 ng/zone for (2) and 20 and 60 ng/zone for (3) in method A and 60 and 180 ng/zone for (1), 130 and 390 ng/zone for (2), 3 and 9 ng/zone for (3) and 70 and 210 ng/zone for (4) in method B. Average recovery was 100.1 % for (1), 100.2 % for (2), 100.6 % for (3) in method A and 100.1 % for (1), 99.9 % for (2) and 100.2 % for (3) in method B.

J. Planar Chromatogr. 33, 511-522 (2020). HPTLC of celecoxib (1) and diacerein (2) on nanosilica gel with n-hexane - ethyl acetate - tetrahydrofuran - glacial acetic acid 35:15:5:4. Quantitative determination by absorbance measurement at 254 nm. The hRF values for (1) and (2) were 59 and 37, respectively. Linearity was between 20 and 320 ng/zone for (1) and 5 and 80 ng/zone for (2). Intermediate precision was below 2 % (n=3). The LOD and LOQ were 7 and 20 ng/zone for (1) and 2 and 5 ng/zone for (2), respectively. Average recovery was 99.9 % for (1) and 99.6 % for (2).