J. Planar Chromatogr. 26, 395-401 (2013). HPTLC of 17alpha-ethinylestradiol (1), 17beta-estradiol (2) and estrone (3) on silica gel with chloroform - acetone - petroleum 11:4:5. The method was combined with the Yeast Estrogen Screen for the detection of estrogenic effects in sediment extracts of a river. Quantitative determination by absorbance measurement at 320 nm. The hRf values of compounds (1) to (3) were 74, 61 and 84, respectively.LOD and LOQ were calculated for the estrogenic model compound (1): LOD was 0.46 pg without prior development of the TLC plate and 0.48 pg after development, LOQ was 0.8 pg without development and 1.6 pg after development.

Acta Parasitologica 58(4), 615–618 (2013). HPTLC on silica gel (HLF plates with 19 scored channels of 9 mm width) for 1) neutral lipids with petroleum ether - diethyl ether - glacial acetic acid 80:20:1, detection by spraying with 5 % ethanolic phosphoric acid; and 2) polar lipids with chloroform - methanol - deionized water 65:25:4, detection by spraying with 10 % cupric sulfate in 8 % phosphoric acid. Quantitative determination by absorption measurement at 610 nm for neutral lipids and 370 nm for polar lipids. Polynomial regression via peak area.

J. Planar Chromatogr. 26, 496-501 (2013). HPTLC of amitriptyline in gastric lavage on silica gel with methanol – ammonia (25%) 197:3. Quantitative determination by absorbance measurement at 209 nm. The hRf value of amitriptyline was 49. Linearity was between 10 and 250 ng/zone. LOD and LOQ were 5 and 17 ng/zone. Recovery (by standard addition) was in the range of 83-92 %. Intermediate intra- and inter-day precision was below 2 %.

J. Planar Chromatogr. 26, 480-485 (2013). HPTLC of garcinol (1) and isogarcinol (2), two polyisoprenylated benzophenones in the fruits of Garcinia indica on silica gel with n-pentane - ethyl acetate 7:3 + 1 drop formic acid. Quantification by absorbance measurement at 327 nm. The hRf values for compounds (1) and (2) were 72 and 62, respectively. Linearity was in the range of 200-1400 ng/zone for (1) and 990-6900 ng/zone for (2). LOD and LOQ were 65 and 200 ng/zone for (1) and 300 and 900 ng/zone for (2). Recovery was in the range of 98.2-101.7 % for both (1) and (2). Intermediate/interday/intra-day precision was below 2 % (n=6).

J. Planar Chromatogr. 26, 427-434 (2013). HPTLC of oseltamivir (1) in pharmaceuticals counterfeited with ascorbic acid (2) on silica gel with methanol - water 3:2 +1 drop ammonia. Quantitative determination by absorbance measurement at 254 nm. The hRf values for (1) and (2) were 70 and 83, respectively. Linearity was between 5 and 14 µg/zone. LOD and LOQ were 2 and 5 µg/zone. Average recovery (by standard addition) was found to be 100.6 %. Intermediate intra- and inter-day precision was below 1.6 %. Comparing with colorimetric method, HPTLC method provided advantages in terms of speed, lower cost, and environmental protection without sacrificing accuracy.

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. Planar Chromatogr. 27, 210-216 (2014). HPTLC of 5-hydroxy-L-tryptophan (1), 5-methyltryptamine (2), L-tryptophan (3) and melatonin (4) on silica gel with propan-2-ol - 25 % ammonia - water 8:1:1. Quantitative determination by absorbance measurement at 280 nm. The hRF values for (1) to (4) were 47, 79, 53 and 85, respectively. Linearity was in the range of 48-720 µg/zone for (1), 38-646 µg/zone for (2), 100-2000 µg/zone for (3) and 108-1737 µg/zone for (4). The intermediate/interday/intra-day precisions were below 3 % (n=5). The LOD and LOQ were 16 and 49 ng/zone for (1), 40 and 122 ng/zone for (2), 116 and 352 ng/zone for (3) and 145 and 439 ng/zone for (4). Mean recovery was between 97.4 and 100.1 % for (1) to (4).

J. Planar Chromatogr. 27, 66-68 (2014). TLC of profenofos in visceral tissues on silica gel with n-hexane - acetone 4:1. Detection by spraying with 10 % sodium hydroxide solution and after 5-10 min, spraying with diazotized sulfanilic acid reagent (0.5 g sulfanilic acid and 1 g sodium nitrite in 100 mL of 10 % v/v hydrochloric acid). The hRF value for profenofos was 45.