Anal. Chem. 79, 2778-2789 (2007). TLC of alkaloids (berberine chloride, palmatine chloride, hydrastine, tetrahydroberberine, hydrastinine hydrochloride and jatrorrhizine) on silica gel with ethyl acetate - methanol - formic acid - water 50:10:6:3. Detection under UV 254 nm. Detection levels were 5 ng/zone each or 14-28 pmol. Desorption electrospray ionization mass spectrometry was investigated as a means to qualitatively identify and to quantify analytes directly from developed normal-phase TLC plates.

CBS 103, 13-15 (2009). HPTLC of azo dyes (Sudan I, II, III, IV, B, Sudan orange G, Sudan red 7B, Para red) in spice samples on caffeine impregnated silica gel with isohexane - methyl ethyl ketone 5:1 with chamber saturation for 10 min. Densitometric absorption measurement at 390, 415, 500, 525 and 550 nm. The limits of detection were approx. 10 mg/kg. Confirmation of suspected compounds in samples by comparison of UV spectra. TLC-MS analysis in positive ESI mode further confirms positive findings.

J. AOAC Int. 96, 1175-1188 (2013). Review of different methods for antifungal screening. Latest developments in HPTLC, where the correlation of bioactivity and quantification was needed to evaluate the antifungal potential. TLC-bioautography was presented as a simple way to screen antifungal activities and two visualization approaches for this technique were described, as well as recent TLC antifungal bioautography applications.

Rapid Commun. Mass Spectrom. 29, 1242-1252 (2015). The paper describes the application of adding neon into helium for Direct Analysis in Real Time (DART) leading to plasma glow visualization to track the metastable gas distributions during surface scanning. The method allows for optimal selection of the coordinates for DART-MS analysis without loss in signal intensity. Visualization of the impact region of the excited gas stream is of high importance for further developments of planar chromatographic hyphenations with DART-MS.

J. of Chromatogr. A 1441, 126-133 (2016). Presentation of a method for the analysis of ergot alkaloids including an ammonium acetate buffered extraction step, followed by a fast liquid-liquid partitioning pre-cleaning and then planar solid phase extraction (pSPE). HPTLC on amino phase with methanol for separation of the ergot alkaloids from the remaining matrix and for focusing them in a single zone. Quantification after dipping the plate in n-hexane – paraffin solution for fluorescence enhancement. The LOD and LOQ was 0.07 and 0.24 mg/kg rye, respectively, expressed as ergocristine, which was well below the currently applied quality criteria limit for rye. The recovery was almost 100 % at relevant spiking levels for different rye flour samples. The pSPE–FLD method was fast, efficient and reliable for screening the total ergot alkaloid content in rye and it was a rapid alternative to the HPLC determination with summing up the individual alkaloids. Furthermore, HPTLC-MS additionally enables the identification of the ergot alkaloid composition by a single mass spectrum, when utilized as a fingerprint, offering an easy differentiation of Secale cornutum from different origins.

J. Chromatogr. A 1529, 93-106 (2017). Presentation of the quantitative effect-directed profiles of 77 industrially and freshly extracted botanicals like herbs, spices, vegetables and fruits, widely used as food ingredients, dietary supplements or traditional medicine for their quality assessment with regard to potential health-promoting activities. Fast assignment of single active compounds and evaluation of their contribution to the overall activity, originating from a food or botanical sample by combination of HPTLC hyphenated with UV/Vis/FLD detection and effect-directed analysis, using the 2,2-diphenyl-1-picrylhydrazyl radical, Gram-negative Aliivibrio fischeri, Gram-positive Bacillus subtilis, acetylcholinesterase and tyrosinase assays. Characterization of bioactive compounds of interest eluted using an elution head-based interface by HPTLC-UV/Vis/FLD-EDA-ESI-(HR)MS method. Demonstration of the excellent quantification power of the method by applying for rosmarinic acid, contents ranged from 4.5 mg/g (rooibos) to 32.6 mg/g (rosemary), for kaempferol-3-glucoside from 0.6 mg/g (caraway) to 4.4 mg/g (wine leaves), and for quercetin-3-glucoside from 1.1 mg/g (hawthorn leaves) to 17.7 mg/g (thyme). The mean repeatabilities (%RSD, n=18) were ≤ 2.2 % for the three compounds and the mean intermediate precision (%RSD, n=3) was 5.2 % over three different days.

J. Chromatogr. A 1533, 213-220 (2018). HPTLC coupled with effect-directed analysis for non-targeted screening of sunflower leaf extract for components exhibiting antioxidant, antibacterial and/or cholinesterase enzyme inhibitory effects. Characterization of the active compounds by HPTLC-electrospray ionization-high resolution mass spectrometry (ESI-HRMS) and HPTLC-Direct Analysis in Real Time (DART)-MS/MS. Identification of the two bioactive diterpenes, (-)-kaur-16-en-19-oic acid and 15-α-angeloyloxy-ent-kaur-16-en-19-oic acid, by NMR spectroscopy after targeted isolation via preparative normal phase flash chromatography and semi-preparative reversed phase HPLC.

by thin-layer chromatography.) TLC of hyperoside on silica with ethyl acetate - butanol - formic acid - water 5:3:1:1, or on polyamide with chloroform - methanol - water 4:1.5:0.1. Detection by spraying with 1 % aluminium chloride. Elution with methanol - water - ethyl acetate 1.5:1:1. Quantification by pulse polarography.