species by validated HPTLC–densitometric method. J. Planar Chromatogr. 26, 248-253 (2013). HPTLC of ardisicrispin A in the roots, stems, leaves, fruits and flowers of Lysimachia nemorum L. (1), Lysimachia nummularia L. (2), Lysimachia vulgaris L. (3), Lysimachia punctata L. (4), Lysimachia thyrsiflora L. (5), Lysimachia ephemerum L. (6), Lysimachia ciliata L. (7), and Lysimachia clethroides Duby (8) on silica gel with chloroform - methanol - water 8:7:1 for (1), (3) and (7) and n-butanol - acetic acid - water 6:1:3 for (2), (4), (5), (6) and (8). Detection by spraying with 25 % sulfuric acid in methanol, followed by heating at 105 ºC for 5 min. Quantitative determination by absorbance measurement at 545 nm. The hRf values for ardisicrispin A in both development systems were 86 and 36, respectively. Linearity was in the range of 2-13 µg/zone. LOD and LOQ were 620 and 950 ng/zone for the chloroform mobile phase and 1890-2880 ng/zone for the n-butanol mobile phase. Average recovery was in the range of 94.3-95.1 %. Intermediate/interday/intra-day precision was below 4 % (n=3).

J. Planar Chromatogr. 26, 56-61 (2013). TLC of ofloxacin (1) and dexamethasone (2) on silica gel with methanol - 0.01 M phosphate buffer 2:3 and pH adjusted to 5 with orthophosphoric acid. Quantitative determination by absorbance measurement at 300 nm for (1) and 240 nm for (2). The hRf values for (1) and (2) were 22 and 60, respectively. Linearity was in the range of 1-6 µg/zone for both (1) and (2). The LOD and LOQ were 260 and 870 ng/zone for (1) and 220 and 740 ng/zone for (2), respectively. Average recovery (by standard addition) for (1) and (2) was 99.2 %. Intermediate/interday/intra-day precision was below 2 % (n=3). The method showed comparable results with a validated HPLC method.

J. Planar Chromatogr. 26, 254-259 (2013). HPTLC of ursolic acid (1), betulinic acid (2), beta-sitosterol (3), and lupeol (4) in the stem bark, root bark and leaves of Alstonia scholaris on silica gel with chloroform - methanol 99:1. Detection by dipping into vanillin-sulfuric acid reagent for 2 s, followed by heating at 96 ºC for 8 min. Quantitative determination by absorbance measurement at 680 nm. The hRf values for (1) to (4) were 18, 27, 57 and 77, respectively. Linearity was in the range of 2-10 µg/zone for (1) and 84) and 4-20 µg/zone for (2) and (3). LOD and LOQ were 330 and 1100 ng/zone for (1), 530 and 1310 ng/zone (2), 290 and 970 ng/zone for (3) and 340 and 1140 ng/zone for (4), respectively. Average recoveries (by standard addition) for (1) to (4) were between 98.9 and 100.5 %. Intermediate/interday/intra-day precision was below 2 % (n=9).

J. Liq. Chromatogr. Relat. Technol. 37, 2021-2035 (2014). HPTLC of thirteen 5-arylidene-2,4-thiazolidinediones on RP-18 with one of six organic solvents: acetonitrile (with increasing acetonitrile content from 55% to 75%), methanol (60–90%), ethanol (40–70%), propanol (35–55%), acetone (55–75%), and dioxane (50–70%) with each modifier in increasing steps of 5%. A quantitative structure-retention relationship study allowed to investigate the retention behavior of these substances.

J. Chromatogr. A 1289, 105-118 (2013). HPTLC of 11 anthocyanes named cyanidin (1), delphinidin (2), malvidin (3), peonidin (4), pelargonidin (5), cyanidin-3-glucoside (6), delphinidin-3-glucoside (7), malvidin-3-glucoside (8), peonidin-3-glucoside (9), pelargonidin-3-glucoside (10) and malvidin-3,5-diglucoside (11) in pomace, feed, juice and wine on silica gel with ethyl acetate - toluene - formic acid - water 50:15:4:6 for the anthocyanidins (1) to (5) and ethyl acetate - 2-butanone - formic acid - water 35:15:6:4 for the anthocyanins (6) to (11). Quantitative determination by absorbance measurement using a multi-wavelength scan at 505 nm for (10), 510 nm for (5), 520 nm for (4) and (9), 530 nm for (1), (3), (6), (8) and (11) and 555 nm for (7). Detection was compared by dipping into a DPPH radical reagent solution (0.5 mM methanolic solution of the DPPH) and into Aliivibrio fischeri bioassay suspension. Linearity was in the range of 180-540 ng/zone for (1), 47-141 ng/zone for (2), 147-441 ng/zone for (3), 24-89 ng/zone for (4), 32-95 ng/zone for (5), 71-343 ng/zone for (6), 63-304 ng/zone for (7), 40-191 ng/zone for (8), 27-131 ng/zone for (9), 16-76 ng/zone for (10) and 45-219 ng/zone for (11). The intermediate precision over several months was below 6.7 % (n=3). The LODs of the anthocyanidins were much better compared to those for anthocyanins. The LOQs for (1) to (11) were below 90 ng/zone, most even below 30 ng/zone and for (9) and (10), the LOQ were even below 7 ng/zone. Radical scavenging as well as bioactivity properties were important complementary detection methods.

J. Liq. Chromatogr. Relat. Technol. 37, 829-840 (2014). HPTLC of amino acids such as leucine (1), isoleucine (2), phenylalanine (3), tyrosine (4), alanine (5), lysine (6), proline (7), serine (8), glutamic acid (9), methionine (10), arginine (11), histidine (12) and tryptophan (13) on silica gel with n-butyl acetate – n-butyl alcohol – ethylene glycol 3:5:2. Detection by spraying with ninhydrin (0.3 % in acetone). The hRF values for amino acids (1) to (13) ranged between 9 and 74. The LODs for (5) and (6) were 100 ng/zone and 60 ng/zone, respectively.

J. Planar Chromatogr. 27, 47-51 (2014). HPTLC of clotrimazole in vaginal tablets on silica gel with toluene - acetone 3:2. Quantitative determination by absorbance measurement at 215 nm. The hRF value for clotrimazole was 27. Linearity was in the range of 1000-2400 ng/zone. The intermediate/interday/intra-day precisions were below 1.3 % (n=6). Recovery was between 99.1 and 100.1 %.

J. Planar Chromatogr. 27, 38-41 (2014). HPTLC of betulinic acid in the green leaves of Achyranthes aspera on silica gel with benzene - ethyl acetate - formic acid 679:227:94. Quantitative determination by absorbance measurement at 210 nm. The hRF value for betulinic acid was 80. The method showed comparable results with a validated HPLC method.