J. Planar Chromatogr. 10, 348-352 (1997). Development of a simple, rapid and reliable TLC method for the identification and quantification of 11-nor-D9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in urine. HPTLC on silica gel 60 WRF254s layers (0.1 mm layer thickness) with dichloromethane - hexane - methanol 7:2:1. Because the chromatograms were evaluated directly by HPTLC-UV and HPTLC-FTIR on-line coupling, it was not necessary to derivatize with fast blue salts or other health-endangering azo dyestuffs. The validated detection limits for THC-COOH (UV: 4 ng/mL, IR: 14 ng/mL) enabled qualitative and quantitative evaluation in the region of the 20 ng/mL cutoff.

Anal. Letters 31, 475-489 (1998). HPTLC of plant tissues, dansylated in a microwave oven, on silica with chloroform - triethylamine 2:1. Quantitation by in situ densitometry at 338/>502 nm. Detection limit 1.8 - 3.0 ng. Precision 0.75-1.39%.

J. Planar Chromatogr. 13, 257-260 (2000). Description of the combined use of overpressured layer chromatography with digital autoradiography for qualitative and quantitative determination of metabolites depending on the complexity and radioactivity content of the matrix investigated. OPLC of extracts of metabolite solutions on HPTLC silica gel layers. Detection by autoradiography.

Proc. Intern. Symp. on Planar Separations Plan. Chrom. 149-152 (2003). Description of an on-line system which provides computer controlled elution of spots from the TLC plate and injection of the eluted substances into MS. All flexibility of TLC is retained, small fraction of MS working time is needed, and any spot on an unlimited number of plates can be selected.

LC-GC Europe 16, Issue 4, 225-229 (2003). A technique for the direct determination of substances from TLC plates by MALDI-MS is discussed. Methods for the generation of quantitative data by adding an internal standard to the development solvent are described and the use of post-source decay-MALDI experiments in conjunction with TLC-MALDI-MS for compound identification is reported.

Anal. Chem. 77, 4098-4107 (2005). Novel method for direct coupling of HPTLC with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) for the analysis of biomolecules. HPTLC of gangliosides on silica gel with chloroform - methanol - water 24:17:4 containing 2 mM calcium chloride, with chamber saturation for 20 min. Detection by dipping for 10 s in 0.3 % (w/v) orcinol in 3 M sulfuric acid, followed by heating at 110 °C. Use of a glycerol as matrix, which provides a homogeneous wetting of the silica gel and a simple and fast preparation protocol. Use of an Er:YAG infrared laser, which ablates layers of 10 µm thickness of analyte-loaded silica gel and provides a soft desorption/ionization of even very labile analyte molecules. The orthogonal time-of-flight mass spectrometer employed in this study, finally provides a high accuracy of the mass determination, which is independent of any irregularity of the silica gel surface. The method is demonstrated by the compositional mapping of a native GM3 (II3-r- Neu5Ac-LacCer) ganglioside mixture from cultured Chinese hamster ovary cells. The analysis is characterized by a high relative sensitivity, allowing the simultaneous detection of various major and minor GM3 species directly from analyte bands. The lateral resolution of the direct HPTLC-MALDI-MS analysis is defined by the laser focus diameter of currently 200 µm. This allows one to determine mobility profiles of individual species with a higher resolution than by reading off the chromatogram by optical absorption.

J. Chromatogr. A 1216 (42), 7096-7101 (2009). Presentation of a TLC-blot–MALDI-IMS method which combines TLC and IMS (imaging mass spectrometry) for use in lipidomics. In comparison with common staining methods the method allows highly sensitive detecion of whole lipids and individual molecular species. Linearity for all lipids ranged approximately over one order of magnitude. Precision (%RSD) was <16 %. The TLC step allows precise separation of complex lipid mixtures into individual lipid classes before MS analysis is performed.

Rapid Commun. Mass Spectrom. 25, 2275-2282 (2011). The authors explored the possibility of the desorption at an angle scanning analysis of surfaces from direct analysis in real time mass spectrometry (DART-MS), including the coupling of planar chromatography with DART-MS. A method for the visualization of the impact region of the DART gas stream was developed, as well as the DART-MS detectability of liquids was increased, improving the capabilities of DART-MS in trace analysis.