J. Planar Chromatogr. 31, 87-91 (2018). HPTLC-direct bioautography of the ethanolic leaf extract of greater burdock (Arctium lappa L.) on silica gel with chloroform – methanol – water 36:4:1. Direct bioautography by dipping into a bacterial suspension of Bacillus subtilis F1276 and Pseudomonas maculicola, followed by incubation for 2 h and dipping into an aqueous solution of 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) vital dye. The main antibacterial compound was analyzed by HPLC-MS.

J. Chromatogr. A 1530, 185-191 (2017). Development of a new spray-on method for applying yeast cells to HPTLC plates, leading to a much higher sensitivity of the planar yeast estrogen screen (p-YES), which can serve as a highly valuable and sensitive screening tool for the detection of estrogenic compounds in various sample matrices such as water and wastewater, personal care products and foodstuff. HPTLC of sample constituents and direct detection of estrogenic compounds by spraying with yeast cells. This resulted in much sharper signals compared to those in previous publications. Satisfying results were achieved using cultures with cell densities of 1000 FAU with reduced signal broadening, thus lower LOQ for estrogenic compounds, e.g. estrone 2 pg/zone, 17β-estradiol 0.5 pg/zone, 17α-ethinylestradiol 0.5 pg/zone and estriol 20 pg/zone. Demonstration of the possibility of the method to characterize profiles of estrogenic activity of wastewater samples with high quality and reproducibility by using native samples from wastewater or even surface water directly applied on HPTLC plates without the need for prior sample treatment.

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%.

J. Planar Chromatogr. 31, 351-354 (2018). HPTLC of 35 simple molecules (acetaminophen, acetanilide, 4-aminobenzoic acid, 2-aminophenol, 2-aminopiridine, 4-aminosalicylic acid, antraquinone, benzocaine, benzoic acid, benzoquinone, caffeine, dihydralazine, 4-dimethylaminbenzaldehyde, diphenylamine, ethyl 4-hydroxybenzoate, eugenol, 8-hydroxyquinoline, indol, isoniazide, 2-naphtol, 1-naphtylamine, 4-nitrophenol, phenol, phenyl salicylate, phenylacetic acid, phenylhydrazine, phloroglucine, resorcinol, salicylamide, salicylic acid, sulfanilamide, sulfanilic acid, thymol, 4-toluidine and vanillin) on RP-2 and RP-18 with 25 chromatographic systems of solvents miscible with water as a diluent (acetone, acetonitrile, dioxane, ethanol, isopropanol, methanol, and tetrahydrofuran). The eluotropic strength was investigated using a design concept that allowed separate estimation of each solvent effect with a relatively small error.

Phytochem. Anal. 29, 452-462 (2018). HPTLC of apigenin(1), luteolin (2), kaempferol (3), quercetin (4), kaempferol‐3‐O‐glucoside (5), quercetin‐3‐O‐glucoside (6), isorhamnetin‐3‐O‐neohesperidoside (7) and rutin (8) in the fruits and aerial parts of Foeniculum vulgare (fennel), Pimpinella anisum (anise), Carum carvi (caraway), Cuminum cyminum (cumin), Coriandrum sativum (coriander), Apium graveolens (celery), Petroselinum crispum (parsley), and Anethum graveolens (dill) on silica gel with ethyl acetate – methanol – water – acetic acid 3:1:1:1. Quantitative determination by absorbance measurement at 254 nm. Heat maps and hierarchical clustering were performed for image processing. The hRF values for (1) to (8) were 97, 90, 83, 73, 30, 17, 7 and 2, respectively. LOD and LOQ were 54 and 166 ng/zone for (1), 52 and 157 ng/zone for (2), 58 and 177 ng/zone for (3), 37 and 112 ng/zone for (4), 57 and 172 ng/zone for (5), 54 and 164 ng/zone for (6), 55 and 169 ng/zone for (7) and 58 and 178 ng/zone for (8), respectively. The intermediate precision was <2 % (n=6). Average recovery was 98.4 % for (1), 92.3 % for (2), 95.3 % for (3), 96.8 % for (4), 94.5 % for (5), 95.6 % for (6), 95.1 % for (7) and 97.3 % for (8).

Proc. Intern. Symposium on TLC with special Emphasis on OPLC, Szeged, 43-44 (1984). OPLC (OPTLC) of 4-cyano-phenylesters, triazine derivatives on silica with methanol - water and acetonitrile - water in seven different proportions. Detection with o-toluidine. The RM-values obtained by OPTLC are in good agreement with RM-values in normal chambers.

behavior of some steroids by OPLC. Proc. Intern. Symposium on TLC with special Emphasis on OPLC, Szeged, 90 (1984). OPLC (OPTLC) of progesterone, cholesterol, corticosterone, aldosterone, cortisol, cortisone on silica with a) petrol ether - ethyl-acetate 6:4, b) chloroform - ethyl acetate - ethanol 90:10:1, c) chloroform - phenol 9:1. Detection with 50 % phosphoric acid and heating at 105 °C for 15 minutes.

(Allopurinol preparation for intravenous injection.) Acta Pharmac. Hungarica 54, 187-192 (1984). TLC of allopurinol on silica with chloroform - methanol 3:2 Detection by UV 254 nm.