J. Planar Chromatogr. 11, 30-33 (1998). Investigation of the interaction of acids and bases with the components of HPTLC layers which lead to greatly altered HPTLC-FTIR spectra in direct HPTLC-FTIR on-line coupling. The cause is an acid-base reaction between the substance and the binder used in the precoated layer. For HPTLC-FTIR analysis of substances with acidic properties water-resistant silica gel 60 WRF 254s HPTLC plates should be used; it is preferable to use standard silica gel 60 F254 HPTLC layers for the analysis of basic substances. When acidic mobile-phase components (e.g. formic acid or acetic acid) are employed the use of water-resistant plates is advisable if HPTLC-FTIR coupling is to be employed for detection. Conversely it is advisable to use standard layers when basis mobile phase components are employed.

Chromatographia 47, 529-536 (1995). 2D-TLC on silica gel with hexane - ethyl acetate 7:3 for the 1st direction and hexane - acetone for the 2nd. Identification by comparison of the retention values. Also HPLC and mass spectrometry.

Chin. J. Anal. Lab. (Fenxi Shiyanshi) 20 (2), 39-41 (2001). TLC on silica gel with methanol - ethyl acetate - petroleum ether (60-90°C) 5:10:4. Detection under UV 254 nm. Quantitation by spectrophotometry after elution. Detection limit 0.08 mg/mL.

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.

Anal. Chem. 76, 6484-6491 (2004). TLC on silica gel with chloroform - methanol - 0.2 % calcium chloride 11:9:2 or chloroform - 2-propanol - 50 mM potassium chloride 10:67:23 for separation of glycolipids, oligosaccharides, lipids, and compounds of environmental and pharmaceutical interest with coupling to an external ion source MALDI-Fourier transform (FT) MS instrument without compromising mass accuracy and resolution of the spectra. Furthermore, when the FTMS, with >70 000 resolving power, has a vibrationally cooled MALDI ion source, fragile glycolipids can be desorbed from TLC plates without fragmentation, even to the point that desorption of intact molecules from “hot” matrixes such as a-cyano-4-hydroxycinnamic acid is possible. TLC of whole brain gangliosides derivatized with orcinol-sulfuric acid reagent. The positions of the fractions on a parallel developed plate were determined; the TLC plates were attached directly to the MALDI target using double-sided adhesive tape or the strip cut from TLC plate. Different matrices were tested.

Phytochem. Anal. 20, 511-515 (2009). Bioautography of alpha-D-glucosidase (1) and beta-D-glucosidase (2) in buffer solution (sodium acetate 4.1 % in water pH=7.5) sprayed onto a silica gel plate. Incubation at room temperature for 60 min for (1) and at 37 °C for 20 min for (2). For detection of the active enzyme, solutions of 2-naphthyl-alpha-D-glucopyranoside or 2-naphthyl-beta-D-glucopyranoside and Fast Blue salt were mixed at a ratio of 1:1 for (1) or 1:4 for (2), and sprayed onto the plate to give a purple background coloration after 2-5 min. Methanol extracts of the aerial parts of Tussilago farfara and Urtica dioica were tested as enzyme inhibitors and visualized as white spots on the TLC plates.

Rapid Commun. Mass Spectrom. 26, 37-42 (2012). Blotting method to transfer analytes separated on wettable HPTLC plates to a hydrophobic RP-8 HPTLC plate. The hydrophobic RP-8 HPTLC plate was wetted with 500 mL methanol then left to evaporate until solvent saturation on the surface was no longer visible. Then the wet plate was placed over the hydrophilic HPTLC plate and pressure was applied to the plates for 10 min. The two plates were separated, and the dried RP-8 plate was analyzed using a liquid microjunction surface sampling probe in combination with electrospray ionization mass spectrometry (LMJ-SSP/ESI-MS). This method provides different means of expanding the utility of the LMJ-SSP approach into the analysis of wettable-phase HPTLC surfaces.