J. Planar Chromatogr. 26, 37-42 (2013). HPTLC of hydrocortisone acetate (1) and 2-phenoxyethanol (2) in cream on RP-18 with water-methanol 4:11. Quantitative determination by absorbance measurement at 270 nm. Linearity was in the range of 4.2-13.0 µg/zone for (1) and 0.8-4.3 µg/zone for (2). LOD and LOQ were 0.6 and 1.7 µg/zone for (1) and 0.2 and 0.5 µg/zone for (2), respectively. Intermediate precision was below 2 %.

J. Planar Chromatogr. 26, 267-273 (2013). HPTLC of glabridin in a Glycyrrhiza glabra formulation on silica gel with toluene - dichloromethane - ethyl acetate 1:1:1. Quantitative determination by absorbance measurement at 287 nm. The hRf value for glabridin was 57. Linearity was in the range of 25-500 ng/zone. LOD and LOQ were 10 and 25 ng/zone. Recovery was in the range of 97.3-103.2 %. Intermediate/interday/intra-day precision was below 2 % (n=6).

J. Planar Chromatogr. 26, 375-378 (2013). TLC of estrone, estradiol, and estriol on silica gel with chloroform - ethyl acetate - acetone 6:2:1. Detecion by dipping into (1) 10 % solution of phosphomolybdic acid (PMA) in methanol, followed by heating at 100 ºC for 10 min; (2) 0.2 % ceric ammonium sulfate in phosphoric acid, followed by heating at 110 ºC for 10 min; (3) 0.2 g manganese(II) chloride in 30 mL water, 30 mL methanol and 2 mL concentrated sulfuric acid, followed by heating at 100-120 ºC for 10-15 min; and (4) 1 g of vanillin in 25 mL of ethanol, 25 mL of distilled water, and 35 mL of ortho-phosphoric acid (85 %), followed by heating at 120-160 ºC for 5-15 min. The lowest detection limit for estrone (75 ng/zone) was achieved using (1) and (3), whereas for estradiol and estriol (both 4.7 ng per zone) by using (2).

J. Planar Chromatogr. 26, 409-416 (2013). TLC bioautography of tylosin (1), spiramycin (2), and erythromycin (3) residues in the meat of Egyptian buffaloes on silica gel with methanol - ethyl acetate - acetone 5:3:2. The hRf values of (1) to (3) were 80, 41 and 20, respectively. Linearity was between 15-120 ng/zone for (1), 50-200 ng/zone for (2) and 1-20 ng/zone for (3). LOD for (1) to (3) were 12, 45 and 2 ng/g, respectively. Recovery (by standard addition) was found to be 84.2-92.2 %. Precision as %RSD was below 7.6 %. Bioautography was performed after development according to the method by J. Michard et al. (Method protocol for the detection of tylosin, spiramycin and virginiamycin in animal feedingstuffs by thin layer chromatography. SIMBAG-FEED Report 4.6. RIKILT, 2005). TLC plates were dried at 60 °C for 30 min in a petri dish and then covered to a thickness of 1.5 mm with agar medium containing the bacterial suspension. After incubation over night at 35 °C about 5 mL of 2,3,5-triphenyltetrazolium chloride solution (0.1 g in 100 mL water) was poured on the medium and re-incubated for some minutes. The inhibition zones were measured and their hRf values were compared with those of antibiotic standards. Detection was considered positive if the hRf value of the sample’s inhibition zone is ±5 % of the standard.

J. Planar Chromatogr. 26, 421-426 (2013). HPTLC of umbelliferone in the leaves of eleven Juniperus species on silica gel with n-hexane - ethyl acetate 7:3 in the first run and dichloromethane - diethyl ether 4:1 in the second run. Quantitative determination by absorbance measurement at 326 nm. The hRf of umbelliferone was 30. Linearity was between 10 and 80 ng/zone. LOD and LOQ were 7 and 23 ng/zone. Average recovery (by standard addition) was 96.3 %. Intermediate intra- and inter-day precision (n = 6) was below 7 %.

J. Planar Chromatogr. 27, 240-244 (2014). HPTLC of sulfide ions derivatized with 4-[p-,Ndimethylamino) phenyl]-2,6-diphenylpyrylium cations (25 μmol) in acetonitrile) on silica gel with a mixture of phosphoric buffer (pH 3.0) - propan-2-ol - acetonitrile 8:8:1. Quantitative determination by scanning and image analysis. The hRF values for thyopyrylium and the derivatization reagent were 73 and 54, respectively. Linearity was in the range of 40-500 pmol/zone. The intermediate/interday/intra-day precisions were below 2 % (n=9). The LOD and LOQ were 11 and 33 pmol/zone, respectively. Recovery was between 98 and 108 %.

J. Planar Chromatogr. 27, 102-106 (2014). HPTLC of betulinic acid in the leaves of Vitex negundo on silica gel with toluene - acetone - formic acid 17:3:2. Detection by spraying with anisaldehyde sulfuric acid reagent, followed by heating at 105 ºC for 5 min. Quantitative determination by absorbance measurement at 445 nm. The hRf value for betulinic acid was 42. Linearity was in the range of 200-1200 ng/zone. The intermediate/interday/intra-day precisions were below 1.3 % (n=3). The LOD and LOQ were 6 and 18 ng/zone, respectively. Recovery was in the range of 99.7-101.5 %.

J. Planar Chromatogr. 27, 107-112 (2014). HPTLC of disulfiram on RP-18 with methanol - water 9:1. Detection by spraying with copper(II) sulfate (0.5 mol/L), followed by heating at 50 ºC for 2 min. Quantitative evaluation with an office scanner at 300 dpi followed by image processing with software. The hRf value for disulfiram was 67. Linearity was in the range of 1-10 μg/zone. The intermediate/interday/intra-day precisions were below 1 % (n=6). The LOD and LOQ were 260 and 860 ng/zone, respectively. Recovery was in the range of 92.4-102.0 %.