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, 395-402 (2022). HPTLC of Padina boergesenii on silica gel with toluene - ethyl acetate 93:7. Detection by spraying with different reagents: anisaldehyde‒sulfuric acid reagent, vanillin‒sulfuric acid reagent, methanolic‒sulfuric acid reagent and Liebermann‒Burchard reagent (1 mL concentrated sulfuric acid, 20 mL acetic anhydride and 100 mL chloroform). Fingerprint analysis under UV light at 254 and 366 nm.

J. Planar Chromatogr. 35, 363-373 (2022). HPTLC of midazolam (1), prochlorperazine (2), citalopram (3) and chlorodiazepoxide (4) in urine on silica gel with cyclohexane - toluene - diethylamine 14:3:3. Quantitative determination by absorbance measurement at 229 nm for (1), 257 nm for (2), 240 nm for (3) and 275 nm for (4). The hRF values for (1) to (4) were 31, 79, 63 and 7, respectively. Linearity was between 3 and 7 µg/zone for (1) to (4). Interday and intra-day precisions were below 5 % (n=3). The LOD and LOQ were 0.5 and 1.6 µg/zone for (1), 0.7 and 2.1 µg/zone for (2), 0.5 and 1.6 µg/zone for (3) and (4).  Average recovery was 95.5 % for (1), 90.5 % for (2), 95.9 % for (3) and 92.5 % for (4).

J Chromatogr A, 1608, 460415 (2019). Samples were acetonitrile extracts of Annona cherimola fruit peel, pulp and seeds (Annonaceae), as well as caffeic acid as standards. HPTLC on silica gel with chloroform – ethyl acetate – propanol 21:2:2 for peel extracts, with chloroform – methanol 9:1 for seed extracts. Derivatization by spraying Dragendorff’s reagent for alkaloids, secondary amines and non-nitrogenous oxygenated compounds.  Effect-directed assay was performed for inhibitors of α-glucosidase. Before sample application, plates were developed with enzyme substrate (2-naphthyl-α-D-glucopyranoside 0.1 % in methanol) and dried 20 min at 60 °C. Then, samples were applied and separated, and mobile phase was removed by heating 10 min at 60 °C. The chromatogram was sprayed with 4 mL enzyme solution (5 unit/mL in 100 mM phosphate buffer,  pH 7.4), liquid excess was removed under lukewarm air stream, the plate was incubated 10 min at 37 °C in a moisture box, followed by spraying chromogenic reagent Fast Blue salt B 0.1 % in water, giving after 2 min white inhibition bands visible on purple background under white light. Plate image was documented under illumination (reflectance mode) with white light. The bands of 3 inhibiting compounds were analyzed in a triple quadrupole mass spectrometer. 1) Full scan mass spectra (m/z 50−1000) in the positive ionization mode were recorded using electrospray ionization (ESI, spray voltage 3 kV, desolvation line temperature 250 °C, block temperature 400 °C) for compounds directly eluted with methanol – acetonitrile through the oval elution head of a TLC-MS interface pump. 2) Compounds were also isolated (either eluted directly from the plate into a vial through the same interface, or scraped from the plate and extracted with methanol – chloroform into a vial), dried, and submitted to HPLC-DAD-MS/MS; MS-MS spectra were recorded in the same conditions, using argon as collision gas and collision cell voltages from -20 and -40 V. Inhibitors were identified as phenolamides (phenylethyl cinnamides): moupinamide (hRF 66 in peels, 56 in seeds), N-trans-feruloyl phenethylamine (hRF 76 in peels), N-trans-p-coumaroyl tyramine (hRF 44 in seeds).

J. Planar Chromatogr. 35, 313-330 (2022).  HPTLC of orange peel extract on silica gel with gradient multiple development using seven different polarity ranges: cyclohexane, cyclohexane - n-heptane 3:7, cyclohexane - methyl tert-butyl ether 43:7, cyclohexane - methyl tert-butyl ether 7:3, cyclohexane - methyl tert-butyl ether 3:7, methyl tert-butyl ether, methyl acetate - ethanol 9:1, ethyl acetate - ethanol - formic acid 44:5:1. Detection by spraying with vanillin reagent (100 mg vanillin dissolved in 9.8 mL ethanol and 0.2 mL sulfuric acid), followed by heating at 100 °C for 2 min. DPPH staining was performed with 2 mL of a DPPH solution (15 mg dissolved in 10 mL of methanol). Bioautography was performed by dipping into Aliivibrio fischeri bacteria suspension for 6 s, followed by measurement of bioluminescence within 15 min. In this sample, more than 50 compounds could be separated.

J Chromatogr A, 1598, 209-215 (2019). Samples were methanolic extracts of honeys from Robinia pseudoacacia (Fabaceae) or from Tilia spp. (Tiliaceae / Malvaceae), as well as standards: abscisic acid (sesquiterpenoid), caffeic acid, chlorogenic acid, cinnamic acid, ferulic acid (phenolic acids), chrysin (flavone), myricetin, quercetin (flavonols), naringenin (flavanone). HPTLC on silica gel with chloroform – ethyl acetate – formic acid 5:4:1. Visualization under UV 254 nm and 366 nm, before and after derivatization by spraying with aluminium chloride (1 % in methanol), which rendered flavone bands bright yellow. Quantitative absorbance measuremet by densitometry at 366 nm. Linearity was in the range of 12,5–200 µg/mL for most standards (25–400 µg/mL for chrysin). Main differences observed in samples: 1) abscisic acid (hRF 56) and chrysin (hRF 82) were present only in Tilia honey samples, quercetin (hRF 55) only in Robinia honey; 2) ferulic acid (hRF 60) was the most prominent blue band in Tilia honey samples (1.35–18.73 g/kg of honey), and less intense in Robinia honey (0–1.24 g/kg of honey). Multivariate analysis was performed in two different ways with principal component analysis.

J Chromatogr Sci, 60 (9), 832-839 (2022). Establishment of two TLC methods for the synchronous estimation of cinnarizine (Cinn) and acefyline heptaminol (Acef) in the presence of reported Cinn/Acef degradation products, as well as theophylline (Theo) as potential impurity of Acef. TLC on silica gel (1) for Cinn with dichloromethane - methanol - formic acid 30:2:1 and (2) for Acef with the same solvents in ratio 150:7.5:4. Quantitative determination by densitometry at 254 nm showed that Cinn and Acef are well separated from their degradation products. The concentration range was 0.2 - 1.8 and 2 - 18 μg/zone for Cinn and Acef, respectively, with mean percentage recoveries of 99.2 / 99.8 and 99.2 / 99.7 for method 1 and method 2, respectively. The method is selective, robust and retained its accuracy in up to 50 % of Cinn/Acef reported degradation products and Theo. Application of the two methods to a coformulated drug product comprising Cinn and Acef with satisfactory results showing statistically no significant differences compared with those obtained by reference ones.