J Chromatogr A, 1619, 460945 (2020). Samples were lamotrigin as standard, or extracted with an oil-in-water microemulsion (10 µL butyl acetate, 4 mL n-butanol, 925 mg sodium dodecyl sulphate, 8.6 mL water) either from patients’ raw plasma (for separation from blood proteins) after spiking, or from commercial tablets dissolved in methanol. TLC on silica gel with a water-in-oil microemulsion of 9 mL butyl acetate, 1 mL n-butanol, 250 mg sodium dodecyl sulphate, 250 µL water. Both optimal microemulsions were predicted using Taguchi orthogonal array and Plackett-Burman design. Evaluation in UV 254 nm, quantification from the digital picture using four image processing software programs. For lamotrigin (hRF 24), limits of quantification were 170 ng for pure drug and 10 ng for spiked plasma. Linearity (in range 20–200 ng/spot) was directly obtained for the calibration curve in spiked plasma; however, for pure drug, linearity was obtained only when using log values of the calculated densities (300–3000 ng/spot).

J Chromatogr A, 1621, 461044 (2020). Samples were five isoquinoline alkaloids (berberine, chelerythrine, chelidonine, coptisine, sanguinarine) either as standard mixture or present in a Chelidonium majus (Papaveraceae) herb extract obtained with HCl 0.05 M in methanol. Separation on TLC and HPTLC silica gel layers with a screening of mobile phases consisting of eutectic mixtures of chemicals and/or phytochemicals. These homogenous stable liquids called DES (deep eutectic solvents) were obtained either simply by mixing, or by mixing followed by heating at 50°C, or by mixing with water for dissolution followed by dehydratation through rotary evaporation. For polarity adjustment, the DES phases were tested pure or diluted with acetone, chloroform, diethyl ether, methanol, or water. Visualization under UV 366 nm. The best separation was obtained with menthol – phenol in equimolar mixture, with 35 % methanol added (hRF values of the selected alkaloids were 33, 39, 79, 20 and 52, respectively).

J Chromatogr A, 1598, 196-208 (2019). Samples were acertone – water 7:3 extracts of Reynoutria japonica (= Fallopia japonica = Polygonum cuspidatum) rhizomes (Polygonaceae) as well as flavanols (catechin, epicatechin, epicatechin gallate, epigallocatechin gallate) and procyanidins (A1, A2, B1–B3 and C1) as standards. HPTLC on diol silica gel with: (MP1) acetonitrile; (MP2) ethyl acetate; (MP3) ethyl acetate – formic acid 90:1; or (MP4) toluene – acetone – formic acid 3:6:1. Prewashing of the plates with mobile phase was needed only with MP1. After drying under hot air stream, derivatization by automated immersion into DMACA (dimethylaminocinnamaldehyde) – HCl solution (60 mg in 13 mL HCl + 187 mL ethanol), followed by 2 min drying under warm air stream. Visualization under UV 366 nm and white light, densitometry in absorption/reflectance mode at 280 nm (before derivatization) or 655 nm (10 min after derivatization). Bands of interest were eluted from layer with acetonitrile – methanol 2:1 through the oval elution head of a TLC-MS interface pump, into a RP18 liquid chromatography guard column, followed by a quadrupole ion trap mass spectrometer. Full scan mass spectra (m/z 150–2000) were recorded in negative mode using electrospray ionization (spray voltage 4 kV, capillary temperature 200◦C, capillary voltage -38.8 V). Monomer gallates to hexamer gallates were detected, separated with MP1, MP2 or MP4; monomers and oligomers (not gallates) were separated with MP3 (up to hexamers) and with MP1 and MP4 (up to decamers). Moreover, enhanced absorption of standards was also studied for influence of mobile phases, of layers (diol silica gel vs. classical silica gel vs. cellulose) and of luminosity (light vs. dark).

J Chromatogr A, 1675, 463167 (2022). Samples were ethanol extracts (and their flash chromatography fractions) of Prunus armeniaca leaves (Rosaceae), as well as betulinic, linolenic, maslinic (= crataegolic), oleanolic, ursolic acids and pygenic acids A (= corosolic acid) and B b as standards. When needed, to improve separation of triterpenoids, reversible pre-chromatographic derivatization was performed in situ by applying 10 µL iodine solution (2 % in chloroform) either before development on the deposit band, or for 2D-HPTLC after a first separation up to 60 mm and before a second orthogonal separation. Layers were covered 10 min with glass sheet after iodine application, and then dried 1 min under cold air stream. HPTLC on silica gel with chloroform – ethyl acetate – methanol 20:3:2, 85:9:6, or 15:2:3), followed by 5-10 min drying under cold air stream (eliminating iodine completely). Post-chromatographic derivatization by immersion (time 2 s, speed 3 cm/s) into vanillin – sulfuric acid (40 mg and 200µL, respectively, in 10 mL ethanol), followed by heating 5 min at 110 °C. Antibacterial effect-directed analysis was performed by immersion (time 8 s) into Bacillus subtilis suspension, followed by 2 h incubation at 37 °C, immersion in MTT solution and 30 min incubation at 37 °C. Active bands were eluted from layer with methanol through the oval elution head of a TLC-MS interface pump, into a single quadrupole mass spectrometer to record full scan mass spectra (m/z 200–1200 in both modes) using electrospray ionization (interface temperature 350°C, heat block temperature 400°C, desolvation line temperature 250°C, detector voltage 4.5kV). Five triterpenoids were identified: betulinic, corosolic, maslinic, oleanolic and ursolic acids, acid, as well as two fatty acids: linolenic and palmitic acid.

J. Planar Chromatogr. 35, 501-507 (2022). HPTLC of β-sitosterol the seeds of Syzygium cumini on silica gel with toluene - ethyl acetate - methanol - glacial acetic acid 6:3:2:1. Detection by dipping into anisaldehyde sulfuric acid solution for 3 s, followed by heating at 80-100 °C for 2-3 min. The assessment of α-amylase inhibitors was performed by dipping into enzyme solution (10 mg α-amylase enzyme in 20 mL of sodium acetate buffer and stored at 2–8 °C) for 2–3 seconds, followed by 90 min humidification in a desiccator and the dipping into a 1 % starch solution as a substrate and put in a humid environment for additional 20–30 min to allow the enzyme–substrate interaction to occur. After a 2–5-min time, the plate was washed or dipped in Gram’s iodine blue, which revealed anti-diabetic activity as blue stains on a white background. The hRF value for β-sitosterol was 87. Further analysis by high‑resolution mass spectrometry.

J. Planar Chromatogr. 35, 481-490 (2022). HPTLC of oleo‑gum resin of raw and purified Commiphora wightii on silica gel with chloroform - ethyl acetate - formic acid - acetic acid
30:9:2:2. Detection by spraying with anisaldehyde sulfuric acid reagent, followed by heating at 105 °C until the development of visible zones. The plate was analyzed under UV light at 254 and 366 nm, and after derivatization at 541 nm. 

J. Planar Chromatogr. 35, 543-546 (2022). HPTLC of diazepam in spiked lemon juice drink on silica gel with chloroform - acetone 4:1 (system 1) and chloroform - methanol - ethyl acetate 14:3:1 (system 2). Detection under UV light at 254 nm. The hRF values for diazepam in systems 1 and 2 were 72 and 88, respectively. 

J. Planar Chromatogr. 35, 403-410 (2022). HPTLC of β-sitosterol (1), ferulic acid (2), berberrubine (3), griffonilide (4) and lithospermoside (5) in Semiaquilegia adoxoides on silica gel with cyclohexane - ethyl acetate 3:1 for (1), toluene - ethyl acetate - methanol - formic acid 50:40:5:12 for (1) and (2), n-butanol - acetic acid - water 21:3:6 for (3) and  chloroform - methanol - water 12:6:1 for (3) to (5). Detection of (1) and (2) by spraying with 10 % sulfuric acid in ethanol, followed by heating at 105 °C. Analysis under UV light at 254 and 366 nm.