J Chromatogr A, 1684, 463582 (2022). Samples were concentrated filtrates of leachates of waste deposition sites, as well as testosterone, flutamide, bisphenol A (BPA) and nitroquinoline oxide (NQO) as standards. Automated Multiple Development on HPTLC silica gel (prewashed with methanol and dried 30 min at 110 °C) with 1) methanol up to 20 mm; 2A) chloroform – ethyl acetate –petroleum ether 11:4:5 or 2B) ethyl acetate – n-hexane 1:1 for flutamide and testosterone, up to 90 mm. Effect-directed analysis was performed by automated spraying 3 mL suspension of BJ1991 yeast (transfected Saccharomyces cerevisiae strain, pure for androgenic activity, with 50 ng/mL testosterone for anti-androgenic assay), followed by 20 h incubation at 30 °C in a closed chamber (90 % relative humidity), by 5 min drying under cold air stream, by spraying 2.5 mL MUG solution (4-methylumbelliferyl-galactopyranoside) and by 15 min incubation at 37 °C in an open chamber. Agonistic and antagonistic activities were detected qualitatively under UV 366 nm (light or dark blue bands, respectively, on blue background) and quantitatively documented using automated scanning at excitation wavelength 320 nm (deuterium lamp), with cut-off filter at 400 nm. Dose-response curves for model compounds were established by regression analysis. Anti-androgenic effective doses at 10 % were 28 ng/zone for flutamide and 20 ng/zone for BPA, without toxicity for the yeast. To exclude cytotoxicity where anti-androgenic activity was observed, the HPTLC layers (either without or after the spraying with MUG) were sprayed with 3 mL resazurin solution (0.01 % in water) and incubated 30 min at 30 °C and 90 % humidity. Cytotoxicity bands appeared as pink zones of resorufin on a colorless background (dihydroresorufin) under white light. Densitometric evaluation in absorption mode at 575 nm (under deuterium and halogen-tungsten lamps, no filter applied). NQO was cytotoxic at its lowest tested dose (1 ng/zone).

Anal. Chim. Acta 1174 (2021) 3387022. Presentation of the next generation LabToGo system OCLab2 which was improved and made more robust e.g. by using print and media technologies in chromatography, so-called office chromatography (OC). The first LabToGo methods were developed in the field of food safety and quality for point-of-care or on-site usage. For application volume study,  HPTLC of different methanolic / propanolic Patent Blue V solutions on HPTLC silica gel with ethyl acetate - methanol - water - acetic acid 65:23:11:1 up to 50 mm. Evaluation in white light and  absorption measurement at 635 nm. For performance tests of plate imaging, HPTLC of benzoic acid and sorbic acid acid on HPTLC with ethyl acetate - toluene - acetic acid 25:25:1. For study of the illumination homogeneity, HPTLC of either sorbic acid, 7-hydroxy-4-methylcoumarin, or Patent Blue V on amino phase, evaluation at 254 nm (sorbic acid), 366 nm (7-hydroxy-4-methylcoumarin) and in white light (Patent Blue V), and in the OCLab2 at 278 nm, 365 nm, and white light, respectively, and scanning the plates at 254 nm 366 nm and 635 nm, respectively. For analysis of food dye mixture by OCLab2, HPTLC on silica gel with ethyl acetate - methanol - water - acetic acid 65:23:11:1 up to 5 cm, drying and capturing of plate images by the OCLab2 at 515-525 nm, 620-630 nm and 465-475 nm, video densitometry and evaluation using the open-source quanTLC software. For analysis of Stevia leave samples, the ethanolic extracts and four calibration levels of a steviol glycoside mixture were applied by OCLab2 for the hydrophilic interaction liquid chromatography (HILIC) separation on HPTLC silica gel with acetonitrile - water 5:1. Derivatization with 2-naphthol sulfuric acid reagent at evaluation in white light. For analysis of water and environmental samples, ink-printing the prepared samples on HPTLC silica gel MS-grade, focusing using acetone - water 4:1 up to 13 mm, drying,  developing with ethyl acetate - toluene 1:1 up to 70 mm, drying and capturing the plate images in white light, 254 nm and 366 nm. For biological detection, spraying the plate with A. fischeri bacteria suspension and capturing of images over 36 min with an exposure time of 60 s and a trigger interval of 3.0 min. 

Sz. Nyiredy, A. Kakuk (eds.): Planar Chromatography 2000, Lillafüred, Hungary, 24-26 June 2000, Res. Inst. for Med. Plants, p. 57-65. Combined application of OPLC-DAR (overpressured layer chromatography - digital autoradiography) and HPLC-RD (high performance liquid chromatography - radioactive detector) solves complex problems appearing during in vivo metabolism study. OPLC-DAR is more sensitive than HPLC-RD and excellent for getting fast information about the existence of conjugates. In case of small amount of sample with low activity, OPLC-DAR is the only possibility for getting qualitative and quantitative information.

Sz. Nyiredy, A. Kakuk (eds.): Planar Chromatography 2000, Lillafüred, Hungary, 24-26 June 2000, Res. Inst. for Med. Plants, p. 109-119. A new off-line OPLC operation called infusion OPLC dramatically reduces the disturbing effect of front of total wetness. Moreover, pre-wetting the layer with a small amount of weak non eluting eluent prior to separation eliminates it totally. Both variations yield more efficient separation compared with conventional transfusion off-line OPLC.

Sz. Nyiredy, A. Kakuk (eds.): Planar Chromatography 2000, Lillafüred, Hungary, 24-26 June 2000, Res. Inst. for Med. Plants, p. 121-132. A variety of modes of multidimensional separation in TLC are shown. Two-dimensional or multidimensional planar chromatography, two-dimensional development on bilayers, coupled layers with stationary phases of decreasing polarity and combination of multidimensional planar chromatographic methods are demonstrated. The greatest strength of multidimensional separation is that compounds are distributed widely over two-dimensional space of high zone capacity. A zone capacity of ca. 1500 could be achieved. Image analyzers might improve quantitation in future.

Sz. Nyiredy, A. Kakuk (eds.): Planar Chromatography 2000, Lillafüred, Hungary, 24-26 June 2000, Res. Inst. for Med. Plants, p. 37-44. OPLC provides efficient separation of different substance groups and the attractive semi-preparative isolation of substances of different type. Characteristics of mobile phase flow and efficiency as well as potentialities of the off-line and on-line mode are shown.

Sz. Nyiredy, A. Kakuk (eds.): Planar Chromatography 2000, Lillafüred, Hungary, 24-26 June 2000, Res. Inst. for Med. Plants, p. 19-25. OPLC of ethinyl estradiole on silica gel with cyclohexane - ethyl acetate - chloroform 3:1:1. Detection by spraying with sulfuric acid and visual evaluation at 366 nm. The method is compared with the Official British and European Pharmacopoeia monographs. Only with the OPLC method it was possible to separate all impurities, i.e. 6-hydroxy derivatives (both isomers), the oxo-derivatives (6-oxo- and 16-oxo-), the 9(11)-dehydro and the 17-epi-derivatives from the estrone and estradiol. The HPLC method of the 3rd European Pharmacopoeia has to be changed slightly in order to analyze all impurities. The British Pharmacopoeia TLC method was not suitable because of its poor selectivity. Both OPLC and HPLC are suitable for purity testing. The OPLC method was preferred for process-validation because it shows a short analysis time and low eluent consumption (tenfold less than HPLC). The HPLC method was used for critical batches due to its better precision (3,5% RSD).

J. Chromatogr. 437, 328-332 (1988). Preparative separation of closely related alkaloids from Papaver and Fumaria species on aluminium oxide by centrifugal TLC with cyclohexane - toluene - diethylamine 320:80:1, 160:40:1 or 160:40:3. Flow-rate 0.5-1.5 mL/min. The rotors (1 mm layer thickness) were prepared from a mixture of 40 g basic aluminium oxide, 10g calcium sulfate hemihydrate and 110 mL water.