J. Planar Chromatogr. 34, 467-477 (2021). HPTLC of five antihypertensive drugs, atenolol (1), amlodipine (2), losartan (3), hydrochlorothiazide (4), and telmisartan (5) on silica gel with chloroform - toluene - methanol - acetone - formic acid 400:300:150:260:3. Quantitative determination by absorbance measurement at 254 nm. The hRF values for (1) to (5) were 7, 12, 45, 56 and 64, respectively. Linearity ranged from 1-25 μg/zone for (1), (3) and (5) and 1-20 μg/zone for (2) and (4). LOD and LOQ were 300 and 900 ng/zone for (1), 130 and 420 ng/zone for (2), 230 and 690 ng/zone for (3), 140 and 430 ng/zone for (4) and 190 and 560 ng/zone for (5). Intermediate precisions were below 1 % (n=9). Mean recovery was 99.3 % fo (1), 100.1 % for (2), 99.7 % for (3), 99.7 % for (4) and 100.3 % for (5).

J. Planar Chromatogr. 34, 337-343 (2021). HPTLC of montelukast (1) and bilastine (2) on silica gel with acetonitrile - ethyl acetate - ammonia 40:60:1. Quantitative determination by absorbance measurement at 282 nm. The hRF values for (1) and (2) were 53 and 27, respectively. Linearity was between 100 and 500 ng/zone for (1) and 200 and 1000 ng/zone for (2). LOD and LOQ were 13 and 40 ng/zone for (1) and 65 and 198 ng/zone for (2). Intermediate precisions were below 2 % (n=3). Recovery was between 98.0 and 99.7 % for (1) and 98.0 and 99.0 % for (2).

J. Pharm. Biomed. Anal. 189, 113488 (2020). Various extracts from red alga Plocamium dilatatum (Plocamiaceae), green alga Codium fragile tasmanicum (Codiaceae) and brown algae Carpoglossum confluens (1), Cystophora platylobium (2) and C. retorta (3) (Sargassaceae), Ecklonia radiata (Lessoniaceae), Hormosira banksia (Hormosiraceae), Phyllospora comosa (4) (Seirococcaceae) were separated on HPTLC silica gel with n-hexane – ethyl acetate – acetic acid 70:27:3. Detection A) for antioxidant activity by spraying with methanolic DPPH solution, followed by waiting for 30 min at room temperature; B) for steroids and terpenes with anisaldehyde - sulfuric acid solution, followed by heating for 10 min at 110°C; C) for carbohydrates and polyols with thymol - sulfuric acid, followed by heating for 15-20 min at 120°C. Image-based evaluation in white light and UV 366 nm. The most active bands were also characterized by ATR-FTIR (= attenuated total reflectance – Fourier-transformed infrared) spectroscopy.

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, 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).

J. Planar Chromatogr. 34, 229-242 (2021). HPTLC of chlorthalidone (1) and metoprolol succinate (2) on silica gel with toluene - methanol - triethylamine 16:4:1. Quantitative determination by absorbance measurement at 230 nm. The hRF values for (1) and (2) were 44 and 23. Linearity was between 200 and 1000 ng/zone for (1) and 800 and 4000 ng/zone for (2). Intermediate precisions were below 2 %. The LOD and LOQ were 29 and 88 ng/zone for (1) and 151 and 459 ng/zone for (2), respectively. Recovery was between 99.9 and 100.9 % for (1) and 100.4 and 101.6 % for (2).

J. Planar Chromatogr. 34, 279-283 (2021). HPTLC of linagliptin on silica gel with toluene - methanol 7:3. Quantitative determination by absorbance measurement at 294 nm. The hRF value for linagliptin was 91. Linearity was between 100 and 500 ng/zone. Intermediate precisions were below 2 % (n=3). The LOD and LOQ were 0.26 and 0.78 ng/zone, respectively. Recovery was between 99.1 % and 101.2 %.