Phytochem. Anal. 28, 74-86 (2017). Review of the latest developments and applications in the field of bioautographic enzyme analysis and assays including acetylcholinesterase, dipeptidyl peptidase 4, glucosidase, lipase, xanthine oxidase, glucose-6-phosphate-dehydrogenase, phosphoglucose isomerase and tyrosinase.

J. Chromatogr. A 1519, 121-130 (2017). Development of an approach to create inhibition chromatograms from the images, which are employed to detect the effect in effect-directed analysis (EDA) with HPTLC, by using the example of the HPTLC-bioluminescence inhibition test. Determination of 50 % effect concentration (EC50) value from the dose-response relationship to describe the strength of the effect, where the known application volumes, instead of the concentration, are used, because the inhibiting compounds are generally unknown and thus their concentrations are also unknown. This enables the calculation of the application volume necessary to achieve 50 % inhibition. Introduction of a new value for comparing effects referred to as reciprocal iso-inhibition volume (R/V), which is used to compare inhibition bands within and between plates. Description of the entire evaluation by the means of two samples from a contaminated site using the HPTLC-bioluminescence inhibition assay.

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. Chromatogr. Relat. Technol. 41, 329-341 (2018). HPTLC of flavonoids (flavone, apigenin, luteolin, chrysin, quercetin dihydrate, myricetin, kaempferide, kaempferol, naringenin and pinocembrin) in propolis, roasted coffee, rose hip, hibiscus, rosemary and sage on silica gel with n-hexane – ethyl acetate – formic acid 20:19:1. Detection by heating the plate at 110 ºC for 3 min, followed by dipping into NP reagent (1 g of diphenylboric acid 2-aminoethyl ester in 200 mL of ethyl acetate) for 1 s, and after drying into paraffin – n-hexane 1:2 or PEG 4000 for 1 s (for enhancement and stabilization of fluorescent zones), followed by drying for 2 min. Qualitative identification under UV 254 and 366 nm. HPTLC–MS(/MS) analysis was also performed using a TLC-MS interface. Some possible interferences with phenolic acids (chlorogenic acid, rosmarinic acid, protocatechuic acid, gallic acid, syringic acid, ellagic acid, trans-cinnamic acid, o-coumaric acid, m-coumaric acid, p-coumaric acid, caffeic acid, ferulic acid, sinapic acid) were also examined.

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, 181-189 (2018). HPTLC profiling of various Jarrah and Manuka honeys on silica gel with toluene – ethyl acetate – formic acid 6:5:1. Detection by spraying with vanillin spraying reagent, followed by heating at 100 ºC for 2-3 min. Qualitative identification under UV 254 and 366 nm. The method allowed an HPTLC fingerprint of non-sugar honey constituents using multiple honey samples and was suitable for the authentication of a honey’s floral source.

J. AOAC Int. 101, 905-913 (2018). Review of the most important advances in the field of planar chromatography between November 1, 2015 and November 1, 2017, including student experiments and reviews, chromatographic systems, apparatus and techniques. Selected applications were well described for each section.

Pharmacogn. Mag. 14, 619-629 (2018). HPTLC of_x000D_ ferulic acid (1), chalcone (2), and catechin (3) in Saraca asoca extract on silica gel with toluene – ethyl acetate – formic acid – methanol 15:15:4:1. Qualitative evaluation at UV 280 nm. The hRF values for (1) to (3) were 79, 88 and 67, respectively.