J. Planar Chromatogr. 34, 203-209 (2021). HPTLC of triclosan in toothpaste on silica gel with n-heptane - methyl tert-butyl ether - acetic acid 920:80:1. Detection by spraying with 2,6-dichloroquinone-4-chloroimide in 50 mL methanol, followed by spraying with an aqueous sodium carbonate solution (1 g/10 mL). Plates were scanned using a flatbed scanner. The hRF value for triclosan was 22. Linearity was between 100 and 1000 ng/zone. The LOD and LOQ were 46 and 91 ng/zone, respectively. Average recovery was 93.2 %.

J. AOAC Int. 103, 1167-1172 (2020). HPTLC of aminexil (1), niacinamide (2) and pyridoxine HCl (3) on silica gel with propanol - toluene - 33 % ammonia solution
20:30:1. Quantitative determination by absorbance measurement at 270 nm. Linearity was between 0.25 and 1.25 µg/zone for (1), 2 and 7 µg/zone for (2) and 3 and 7 µg/zone for (3). Intermediate precision was below 2 % (n=3). The LOD and LOQ were 20 and 60 ng/zone for (1), 180 and 540 ng/zone for (2) and 140 and 430 ng/zone for (3), respectively. Average recovery was 100.1 % for (1) and (2) and 101.1 % for (3). 

J. Chromatogr. A 1568, 188-196 (2018). Application of an advantageous combination, the desorption-based direct analysis in real time mass spectrometry (DART-MS) immediately after direct bioautography (DB), i.e., in the presence of microorganisms, bioassay medium and substrate reagent. The method offers a straightforward and efficient mass spectrometric detection of bioactive analytes within the bioautogram. It discriminated microorganism cells and highly polar bioassay medium ingredients which could otherwise stress the MS system. Investigation of DB-DART-MS for bioactive compounds in cosmetics using the Bacillus subtilis and Aliivibrio fischeri bioassays for detection of Gram-positive and Gram-negative antimicrobials, respectively, and the planar yeast estrogen screen for detection of estrogen-effective compounds. Study of the influences of three different bioassay matrices on the analyte response and DB-DART-MS performance on different layers (NP and RP) on the example of parabens in hand creams. Ion suppression was enhanced with increasing culture medium complexity. The mass spectrometric quantification by DB-DART-MS at the ng-level in situ each different bioautogram was verified by comparison to HPTLC-DART-MS. The total paraben content of hand creams 1 and 2 was 0.17–0.20% and 0.30–0.34%, respectively, depending on the method used. It proved that DB-DART-MS is a reliable qantitative bioanalytical hyphenation.

Pharmazie 62, 803-812 (2007). TLC of anthocyanins in aronia, blueberry and lingonberry extracts and the respective preparations (e.g. capsules, lozenges, granulate) on silica gel with ethyl acetate - water - anhydrous formic acid 10:3:2 and 10:4:1. Detection in white light prior and after spraying with iron(III)chloride solution or with vanillin phosphoric acid reagent.

CBS 107, 5-7 (2011). HPTLC of coenzyme Q10 in toluene extracts of soft gel capsules on silica gel (pre-washed by development from both sides with methanol) with toluene in the horizontal developing chamber from both sides. Detection under UV 254 nm. The hRf value of coenzyme Q10 is 20. Quantitative absorption measurement at 282 nm, evaluation via peak height. Linearity was in the range of 20-50 ng/band. Polynomial calibration ranged 20-150 ng/band. The parallel analysis of 60 samples (10 samples each from 6 batches) and 12 standards required only 86 min. The test for content uniformity was performed with 10 samples according to the European Pharmacopoeia and the USP 34 and the requirements were met.

J. Chromatogr. A 1532, 198-207 (2018). Development of a method to analyze the efficiency of a diverse set of natural deep eutectic solvents (NADES) for the extraction of compounds of interest from two model plants, Ginkgo biloba and Panax ginseng. HPTLC on silica gel with toluene – ethyl acetate – acetone – methanol 50:25:25:3 for ginkgolides in Ginkgo biloba leaves; with ethyl acetate – acetic acid – formic acid – water 100:11:11:27 for phenolics in Ginkgo biloba leaves; with toluene – ethyl acetate – acetic acid 40:10:1 for ginkgolic acids in Ginkgo biloba leaves; with chloroform – ethyl acetate – methanol – water 15:40:22:10 for ginsenosides in Panax ginseng leaves and stems. The six different NADES were combinations of two or three compounds mixed in defined molar ratios, e.g. malic acid – choline chloride 1:1, malic acid – glucose 1:1, choline chloride – glucose 5:2, malic acid – proline 1:1, glucose – fructose – sucrose 1:1:1 and glycerol – proline – sucrose 9:4:1. Processing the data obtained by multivariate data analysis showed differences between the extracts. Discussion of the foreground of application of NADES in green chemistry and the advantages of NADES as green solvents used in novel green products for the food, cosmetics and pharmaceuticals.

J. Liq. Chrom. Rel. Technol. 27, 1981-1992 (2004). Study of the interaction between cholesterol and non-ionic surfactants by reversed-phase TLC using cholesterol-impregnated TLC plates and methanol - water mixtures. TLC on aluminum oxide impregnated by overnight pre-development in a solution of cholesterol dissolved in chloroform - acetone 1:1. 20 surfactants were tested (Arcopal, Sapogenat, Tween, Genapol, Myrj, and Brij). The intercept obtained from linear regression anal. (RM0), being characteristic for the strength of interaction, and the slope (b), being related to the surface area of surfactants in contact with cholesterol, were detected. Stepwise regression anal. (SRA) was performed to find relation between the structural parameters of surfactants and strength of interaction. Stacking interaction exists between cholesterol and the aromatic ring of the surfactants. The number of ethylene oxide units and length of the carbon chain in the surfactant molecules have significant effect on the strength of the interaction between the compounds studied.

CBS 100, 2-5 (2008). HPTLC of photodegraded UV filters and sunscreen on silica gel LiChrospher prewashed with methanol. AMD 2 development of UV filter standards photodegradation products with diisopropylether - n-hexane in 6 steps over 50 mm without preconditioning, and of sunscreen samples photodegradation products with t-butylmethylether - n-hexane in 7 steps over 50 mm with preconditioning, followed by drying at 120 °C for 30 min. Detection at 254 and 366 nm, followed by biodetection via dipping the plate in a Vibrio fischeri solution for 1 s and evaluation with the Bioluminizer (exposure time 55 s). Densitometric evaluation by multi-wavelength scan at 200-400 nm.