(Peel). J. Planar Chromatogr. 30, 510-515 (2017). HPTLC of protocatechuic acid (1) and quercetin 4ʹ-O-β-D-glucopyranoside (2) in Allium cepa on silica gel with toluene – ethyl acetate – formic acid 3:6:1. Quantitative determination by absorbance measurement at 275 nm. The hRF values for (1) and (2) were 56 and 5, respectively. Linearity was between 100 and 700 ng/zone for (1) and (2). LOD and LOQ were 32 and 92 ng/zone for (1) and 30 and 92 ng/zone for (2). The intermediate precision was <2 % (n=6). Recovery ranged from 98.1 to 99.6 % for (1) and 98.2 to 99.9 % for (2).

species. J. Planar Chromatogr. 30, 386-391 (2017). HPTLC fingerprints of 7 Origanum L. species on silica gel with toluene – ethyl acetate 19:1. Detection by spraying half of the chromatographic plate with an ethanolic mixture (ratio not given) of a 1 % vanillin solution and a 5 % sulfuric acid solution, followed by heating at 105 °C, while spraying the other half with 0.2 % 2,2-diphenyl-1-picrylhydrazyl (DPPH*) reagent. Detection under white light illumination. Principal component analysis (PCA) allowed for the determination of different chemotypes of the examined oils.

Rev. Bras. Farmacogn. 28/1, 92-101 (2018). HPTLC fingerprint of Eugenia uniflora on silica gel with ethyl acetate – formic acid – water 18:1:1. Detection by spraying with natural products reagent followed by PEG reagent. Qualitative identification under UV 365 nm. The hRf values of gallic acid, myricetrin and ellagic acid were 71, 34 and 38, respectively.

J. Chromatogr. A 1526, 157-166 (2017). Introduction of a promising alternative method for protein analysis using HPTLC with its high level of variability regarding the chromatographic system (multiple mobile and stationary phases, even mixed) and manifold detection as well as hyphenation possibilities. Silica gel, cellulose, and different RP layers were investigated with regard to their applicability for HPTLC-immunostaining. HPTLC of intact proteins on silica gel with 2-butanol – pyridine – ammonia – water 39:20:10:31; on cellulose with 2-butanol – pyridine – ammonia – water 32:30:11:25; and on RP phase with acetonitrile – trifluoroacetic acid – water 400:30:37. After development the plate was incubated with Tween20 as blocking reagent in a small vessel to inhibit unspecific binding of the antibodies to the surface. Then the plate was incubated for 2 h with the primary antibody solution and after washing with the secondary antibody for 1 h. Detection by incubating the plate in a dying solution containing 0.06% 3,3',5,5'-tetramethylbenzidine, 0.2% dioctyl sulfosuccinate sodium salt, 0.7% citric acid monohydrate, 1.8% sodium hydrogen phosphate dihydrate, 25% ethanol, and 1.5‰ dihydrogen dioxide, until blue zones appeared under white light. For the example analysis of beta-lactoglobulin on silica gel using antibovine beta-lactoglobulin antibodies, linearity was in the range of 75-2000 ng, the LOD was 62 ng/zone, the LOQ 93 ng/zone, and the accuracy 98.3%.

Phytochemistry 157, 92-102 (2019). HPTLC of monogalactosyldiacylglycerol (1) and digalactosyldiacylglycerol (2) in the leaves of basket willow (Salix viminalis L., Salicaceae, Malpighiales), cabbage (Brassica oleracea L., Brassicaceae, Brassicales), pea (Pisum sativum, Fabaceae, Fabales), roseroot (Rhodiola rosea L., Crassulaceae, Saxifragales), meadow buttercup (R. acris L., Ranunculales), garlic (Allium sativum L., Amaryllidaceae, Asparagales) and Ipomoea tricolor Cav. (Convolvulaceae, Solanales) on silica gel with acetone – benzene – water 91:30:8. Qualitative identification under UV light at 254 and 366 nm. The hRF values were 20-26 for (1) and 63-77 for (2).

Pharmacogn. Mag. 14, 437-443 (2018). HPTLC fingerprinting of 7 plant species from northeast Brazil (Anacardium occidentale, Annona muricata, Guazuma ulmifolia, Phyllanthus niruri, Psidium guajava, Punica granatum, and Spondias mombin) using caffeic acid (1), quercetin (2), gallic acid (3) and catechin (4) as chemical markers on silica gel with toluene – ethyl acetate – methanol – formic acid 85% 75:25:25:6. Detection of (1) and (2) by spraying with natural products reagent A + 5 % polyethylene glycol 400. Detection of (3) and (4) by spraying with ferric chloride and vanillin-HCl, respectively. Qualitative evaluation under UV light at 254 and 365 nm. The hRF values for (1), (2) and (4) in Anacardium occidentale were 30, 42 and 21, respectively. The hRF value for (4) in Annona muricata was 16. The hRF values for (1) and (4) in Guazuma ulmifolia were 44 and 20, respectivley. The hRF values for (1) and (4) in Psidium guajava were 3 and 18, respectively. The hRF value for (1) in Punica granatum was 33. The hRF values for (1) to (4) in Spondias mombin were 31, 43, 31 and 17, respectively.

J. Planar Chromatogr. 31, 383-388 (2018). HPTLC of cocaine hydrochloride (1) and levamisole hydrochloride (2) on silica gel with cyclohexane – toluene – diphenylamine 75:15:10. Quantitative determination by absorbance measurement at 230 nm. The hRF values for (1) and (2) were 24 and 48, respectively. Linearity was between 200 and 2400 ng/zone for (1) and 100 and 1200 ng/zone for (2). LOD and LOQ were 14 and 42 ng/zone for (1) and 6 and 19 ng/zone for (2), respectively. The intermediate precision was <2 % (n=6). Average recovery was 99.8 % for (1) and 99.9 % for (2).

J. Planar Chromatogr. 31, 461-468 (2018). HPTLC of dabigatran etexilate mesylate on silica gel with methanol ‒ ethyl acetate ‒ benzene 3:4:4. Quantitative determination by absorbance measurement at 225 nm. The hRF value for dabigatran etexilate mesylate was 82. Linearity was between 0.3 and 3 μg/zone. LOD and LOQ were 0.03 and 0.09 μg/zone. The intermediate precision was <2 % (n=3). Average recovery was 98.9 %.