J. Planar Chromatogr. 32, 447-451 (2019). HPTLC of Fritillaria cirrhosa on silica gel with ethyl acetate - methanol - ammonia solution - water 180:20:10:1. Bioautography by dipping into a 0.15 mg/mL solution of substrate Gly-Pro-p-nitroanilide hydrochloride in 50 % of ethanol, followed by ethanol removal in the hood and dipping into a 10 U/L DPP IV enzyme solution in TrisHCl buffer (pH 8.2, 70 mM), followed by incubation at 37°C for 40 min. Detection by dipping into a solution of 0.5 % sodium nitrite in 1.2 M hydrochloric acid, followed by drying slightly for 5 min and dipping into 0.05 % N-(1-naphthyl)ethylenediamine dihydrochloride solution. Further analysis by mass spectrometry using a TLC interface. The hRF value for the dipeptidyl peptidase IV inhibitor was 58.

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.

J. Liq. Chromatogr. Relat. Technol. 42, 266-273 (2019). HPTLC of aqueous, fermented plant preparations from Chamomilla recutita L. (1), Allium cepa L. (2), Equisetum arvense L. (3) and Hamamelis virginiana L. (4) of different harvest years on silica gel with ethyl acetate - toluene - formic acid - water 16:4:3:2. The method was combined with effect-directed analysis (EDA) and high-resolution mass spectrometry (HRMS). For α-/β-glucosidase assays, the plate was sprayed with 2 mL substrate solution (60 mg 2-naphthyl-α-D-glucopyranoside or 2-naphthyl-β-D-glucopyranoside in 50 mL ethanol), then sprayed with 1 mL sodium acetate buffer and 2 mL enzyme solution (500 units α-glucosidase), followed by incubation at 37 ºC for 10 min. Analysis of multi-potent compounds was also performed using the 2,2-diphenyl-1-picrylhydrazyl reagent and Gram-positive Bacillus subtilis assays, followed by recording of elution head-based HPTLC-ESI-HRMS spectra. 

Planta Med. 83(17), 1321-1328 (2017). Benzoyl-aconine esters (lipo-alkaloids) produced by transesterification of aconitine (isolated from Aconitum sp.) with long-chain fatty acids were purified by a multistep chromatographic method, including cyclodextrane gel filtration chromatography, centrifugal planar chromatography on aluminium oxide layer using cyclohexane – chloroform – methanol 70:30:1 followed by 70:30:3 and/or preparative thin-layer chromatography on aluminium oxide layer with toluene – acetone – ethanol – concentrated ammonia 70:40:10:3.

Planta Med. 83(17), 1321-1328 (2017). Benzoyl-aconine esters (lipo-alkaloids) produced by transesterification of aconitine (isolated from Aconitum sp.) with long-chain fatty acids were purified by a multistep chromatographic method, including cyclodextrane gel filtration chromatography, centrifugal planar chromatography on aluminium oxide layer using cyclohexane – chloroform – methanol 70:30:1 followed by 70:30:3 and/or preparative thin-layer chromatography on aluminium oxide layer with toluene – acetone – ethanol – concentrated ammonia 70:40:10:3.

J. Planar Chromatogr. 32, 41-46 (2019). HPTLC of the five coccidiostats monensin (1), narasin (2), nigericin (3), robenidine (4) and salinomycin (5) on silica gel with at least two developments with methanol. After evaporation of the solvent, a TLC–MS interface was used for solvent front position extraction (SFPE) and further analysis by liquid chromatography–tandem mass spectrometry (LC–MS/MS). 
 

Chinese J. Pharm. Anal. (Yaowu Fenxi Zazhi) 24 (1), 30-34 (2004). TLC on silica gel with chloroform - acetone - diethylamine 5:4:1. Detection under UV 254 nm. Identification by standard comparison. Use of silver gel as the surface enhanced subtract placed on the separated spots for measurement of FT-SERS. Investigation of the minimum detection amount for the compound, and the difference between the SERS and solid spectra.

Anal. Chem. 77, 1207-1215 (2005). The use of desorption electrospray ionization for coupling TLC with MS was demonstrated for prewashed wettable unpolar C18, C8, and C2 and for polar silica gel phases. The experimental setup and its optimization are described as plate positioning was a crucial factor of influence on the MS signal. TLC of rhodamine dyes on RP-8 and RP-2 phases with methanol – water containing 200 mM ammonium acetate 4:1, MS analysis in the positive ion mode via SRM. TLC of FD&C dyes on wettable RP-18 phases with water – acetone 7:3 containing 500 mM ammonium acetate, MS analysis in the negative ion full scan mode. TLC of a mixture of aspirin, acetaminophen, and caffeine from a medicinal formulation on silica gel with ethyl acetate – acetic acid 99:1, MS analysis in the positive ion full scan mode. The capability of detection was in the µg-range on silica gel phases and not as good as on unpolar phases.