J. Planar Chromatogr. 32, 211-222 (2019). HPTLC of 24β-ethylcholesta-5,22E,25-triene-3β-O-D-glucoside (1), clerodinin-A (2), 24β-ethylcholesta-5,22E,25-triene-3β-ol (3), and lupeol (4) in three closely related Clerodendrum species (C. inerme, C. multiforum, and C. viscosum) on silica gel with toluene - ethyl - acetate - methanol - acetic acid 13:6:2:1. Detection by dipping into anisaldehyde - sulfuric acid - acetic acid 1:5:95, followed by air drying for 10 min and heating at 135 °C for 7 min. Quantitative determination by absorbance measurement at 560 nm. The hRF values for (1) to (4) were 35, 82, 89 and 96, respectively. Linearity was between 100 and 500 ng/zone for (1) to (4). The intermediate precision was below 3 % (n=9). The LOD and LOQ were 20 and 70 ng/zone for (1), 40 and 150 ng/zone for (2), 40 and 120 ng/zone for (3) and 50 and 150 ng/zone for (4), respectivley. Recovery rate was between 99.0 and 101.0 % for (1) to (4).

J. Planar Chromatogr. 32, 237-241 (2019). HPTLC of protocatechuic acid (1) and quercetin (2) in the fruits of Carissa carandas on silica gel with toluene - ethyl acetate - formic acid 6:3:1. Quantitative determination by absorbance measurement at 310 nm. The hRF values for (1) and (2) were 57 and 61, respectively. Linearity was between 100 and 600 ng/zone for (1) and (2). The intermediate precision was below 2 % (n=9). The LOD and LOQ were 33 and 100 ng/zone for (1) and 28 and 85 ng/zone for (2), respectivley. Recovery rate was between 96.9 and 99.8 % for (1) and 97.9 and 98.8 % for (2).

J. Planar Chromatogr. 32, 231-235 (2019). HPTLC of mangiferin in Canscora perfoliata on silica gel with ethyl acetate - methanol - formic acid - acetic acid - water 10:1:1:1:1. Quantitative determination by absorbance measurement at 254 nm. The hRF value of mangiferin was 53. Linearity was between 0.1 and 0.5 µg/zone. The intra-day and interday precisions were below 1 % (n=7). The LOD and LOQ were 30 and 50 ng/zone, respectively. Recovery rate was 97.5 %.

J. Planar Chromatogr. 32, 197-203 (2019). HPTLC of equol (1), artemisinin (2) and caffeine (3) on silica gel with methyl t-butyl ether - cyclohexane 1:1 for (1), cyclohexane - ethyl acetate 7:3 for (2) and ethyl acetate - acetone 7:3 for (3). The plate was scanned with a DART–TOF MS system to optimize the measurement conditions. The hRF values for (1) to (3) were 71, 63 and 53, respectively. LOD and LOQ were 1.2 and 1.8 µg/zone for (1), 225 and 315 ng/zone for (2) and 270 and 490 ng/zone for (3), respectivley.

J. Planar Chromatogr. 32, 191-196 (2019). HPTLC of phenolic compounds in 11 dark beers, 25 light beers, 10 non-alcoholic beers and 4 malt beers on silica gel with ethyl acetate - formic acid - acetic acid - water 50:55:55:13. Detection by dipping into a (1) 0.5 % methanolic solution of 2-aminoethyl diphenylborinate (natural product reagent or Neu’s reagent), followed by dipping into a 5 % methanolic polyethylene glycol (PEG) 400 solution for enhancement and stabilization of the fluorescent zones, or (2) 0.2 % methanolic DPPH radical solution. Documentation under white light and UV 366 nm. Zones at hRF values of 8, 13, 36, 45, 52 and 85 had the most impact on the principal component (PC) analysis and were recognized as markers for discrimination between dark and non-alcoholic beers. HPTLC-ESI-HRMS/MS² analysis allowed the identification of desdimethyl-octahydro-iso-cohumulone (hRF 85) and iso-n/ad-humulone (hRF 95) as the most active bands with radical scavenging property.

J. Planar Chromatogr. 32, 103-108 (2019). HPTLC of ursolic acid (1), β-sitosterol (2), lupeol (3) and quercetin (4) in the aerial parts of Ichnocarpus frutescens on silica gel with toluene - ethyl acetate - formic acid 80:20:1. Quantitative determination by absorbance measurement at 500 nm for (1), 550 nm for (2), 650 nm for (3) and 310 nm for (4). The hRF values for (1) to (4) were 66, 70, 75 and 42, respectively. Linearity was between 100 and 600 ng/zone for (1) to (4). The intermediate precision was below 2 % (n=3). The LOD and LOQ were 60 and 182 ng for (1), 80 and 242 ng for (2), 50 and 151 ng for (3) and 45 and 137 ng for (4), respectivley. Recovery rate was between 96.9 and 100.1 % for (1) to (4).

J. Planar Chromatogr. 32, 95-102 (2019). HPTLC of trigonelline in the seeds of Fenugreek
(Trigonella foenum-graecum) on silica gel with n-propanol - methanol - water - ammonia 40:6:15:1. Quantitative determination by absorbance measurement at 270 nm. The hRF value of trigonelline was 40. Linearity was between 100 and 1200 ng/zone. The intermediate precision was 0.7 % (n=6). The LOD and LOQ were 14 and 52 ng/zone, respectively. Recovery rate was 100.1 %.

J. Planar Chromatogr. 32, 141-147 (2019). HPTLC of sofosbuvir (1) and velpatasvir (2) on silica gel with methylene chloride - methanol - ethyl acetate - 25 % ammonia 5:1:3:1. Quantitative determination by absorbance measurement at 275 nm. The hRF values for (1) and (2) were 28 and 84, respectively. Linearity was between 100 and 2000 ng/zone for both (1) and (2). The intermediate precision was below 2 % (n=3). The LOD and LOQ were 30 and 90 ng/zone for (1) and 28 and 83 ng/zone for (2), respectively. Recovery rate was 100.0 % for (1) and 100.2 % for (2).