J. Planar Chromatogr. 34, 361-366 (2021). HPTLC of 19 iridoids, including ten iridoid glycosides (catalpol, aucubin, ajugol, hastatoside, loganin, geniposide, harpagoside, verbenalin, agnuside, nuzhenide), six secoiridoid glycosides (harpagide, sweroside, swertiamarin, gentiopicroside, oleuropein, amarogentin) and three nonglycosylated iridoids (loganic acid, genipin, valtrate) in samples of Gentiana lutea, Verbena officinalis, Olea europaea and Harpagophytum procumbens on silica gel with nine different mobile phases. Detection by spraying with anisaldehyde reagent, vanillin reagent, sulfuric acid reagent, respectively, followed by heating at 100 °C for 3 min. After derivatizing the plate with Ehrlich’s reagent, the plate was heated at 100 °C for 5 min. Digital images were recorded under UV light at 254 nm and 366 nm. The data is part of a HPTLC database under development for different families of phytochemicals.

J. Planar Chromatogr. 34, 315-322 (2021). HPTLC of quercetin (1) and isorhamnetin (2) in the fruits of Hippophae rhamnoides on 3 % sodium acetate silica gel with dichloromethane - ethyl acetate - formic acid 7:3:1. Detection by spraying with 1 % ethanol solution of aluminum trichloride. Quantitative determination by absorbance measurement at 390 nm. The hRF values for (1) and (2) were 48 and 64, respectively. Linearity was between 60 and 420 ng/µL for (1) and 40 and 440 ng/µL for (2). The intermediate precision was below 5 % (n=6). LOD and LOQ were 50 and 165 ng for (1) and 50 and 167 ng for (2). Recovery was between 97.1 and 103.4 % for (1) and 98.1 and 103.9 % for (2).

J. Planar Chromatogr. 34, 345-351 (2021). HPTLC of Croton tiglium extracts on silica gel with toluene - ethyl acetate 9:1, toluene - ethyl acetate - methanol 6:4:1, toluene - ethyl acetate 3:2, toluene - ethyl acetate - methanol 4:6:1. Detection by spraying with anisaldehyde - sulfuric acid reagent. Identification of steroids and terpenoids on silica gel with toluene - ethyl acetate 9:1 and detection by spraying with the Liebermann‒Burchard reagent, followed by heating at 100 °C. Acidic compounds were analyzed on silica gel with toluene - ethyl acetate 9:1, followed by spraying with bromocresol green reagent. Coumarins were analyzed on silica gel with toluene - ethyl acetate - methanol 4:6:1, followed by spraying with alcoholic potassium hydroxide reagent and visualization under UV light at 366 nm.

J. Planar Chromatogr. 34, 297-305 (2021). HPTLC of four kinds of hydroxynaphthoquinone ingredients, namely β-hydroxyisovaleryl shikonin (1), L-shikonin (2), β-acetoxyisovaleryl shikonin (3), and acetyl shikonin (4) in the roots of Arnebia euchroma on silica gel with cyclohexane - dichloromethane - ethyl acetate - formic acid 50:90:6:11. Quantitative determination by absorbance measurement at 520 nm. The hRF values for (1) to (4) were 20, 30, 50 and 60, respectively. Linearity was between 56 and 678 ng/zone for (1), 64 and 768 ng/zone for (2), 132 and 1590 ng/zone for (3) and 253 and 3042 ng/zone for (4). Intermediate precisions were below 3 % (n=3). Average recovery was 99.5 % for (1), 100.6 % for (2), 98.6 % for (3) and 97.0 % for (4).

J. Planar Chromatogr. 34, 253-261 (2021). HPTLC of emtricitabine (1) and tenofovir alafenamide fumarate (2) on silica gel with ethyl acetate - n-hexane - methanol - ammonia solution 20:20:10:1. Quantitative determination by absorbance measurement at 260 nm. Linearity was between 400 and 2000 ng/zone for (1) and 50 and 250 ng/zone for (2). Intermediate precisions were below 2 % (n=3). The LOD and LOQ were 29 and 87 ng/zone, respectively. Recovery was between 100 and 102 % for (1) and 100 and 103 % for (2).

J. Planar Chromatogr. 34, 189-195 (2021). HPTLC of tacrolimus on silica gel with acetonitrile - ethyl acetate - glacial acetic acid 60:20:20:1. Detection by spraying with anisaldehyde reagent (0.5 mL of p-anisaldehyde was mixed with 10 mL of glacial acetic acid, 85 mL of methanol and 5 mL of sulfuric acid), followed by heating at 100 °C for 3 min. Quantitative determination by absorbance measurement at 366 nm. The hRF value for tacrolimus was 20. Linearity was between 20 and 140 ng/zone. Intermediate precisions were below 3 % (n=3). The LOD and LOQ were 6 and 17 ng/zone, respectively. Mean recovery was 101.6 %.

J. Planar Chromatogr. 34, 263-270 (2021). HPTLC of quetiapine fumarate (1) and its related genotoxic impurities 2-chloroaniline (2) and 2-aminodiphenylsulide (3) on silica gel with ethyl acetate - ethanol - n-heptane 5:1:4. Quantitative determination by absorbance measurement at 229 nm. The hRF values for (1) to (3) were 13, 57 and 76, respectively. Linearity was between 100 and 600 ng/zone for (1) and 10 and 60 ng/zone for (2) and (3). Intermediate precisions were below 2 %. The LOD and LOQ were 0.9 and 2.8 ng/zone for (1), 0.3 and 0.9 ng/zone for (2) and 0.2 and 0.5 ng/zone for (3), respectively. Recovery of the impurity in quetiapine fumarate ranged between 99 % and 101 %.

J. Planar Chromatogr. 34, 197-202 (2021). HPTLC of L‑proline (1) and L‑lysine (2) derivatives on silica gel with ethanol - toluene 2:3 in a horizontal chamber. Amino acids pre-chromatographic derivatization with 2-propanol - phenyl isothiocyanate - phosphate buffer pH 12 7:1:1. Detection by spraying with a solution of 4 % sodium azide, 0.5 % starch, pH 5.5, followed by exposure to iodine vapor for 20 s. Plates were scanned with an office scanner and the zones were converted to peaks by software. The hRF values for (1) and (2) were 32 and 67, respectively. Intermediate precisions were below 9 % (n=6). The LOD was 0.05 nmol/zone for (1) and 0.05 nmol/zone for (2). Recovery was between 94 and 104 % for (1) and 82 and 104 % for (2).