CBS 93, 14-15 (2004). HPTLC of heterocyclic aromatic amines on silica gel WRF (prewashed with methanol by chromatography followed by drying at 120 °C for 30 min) with a 6 step gradient with diethyl ether, methanol and chloroform, with alkaline conditioning via gas phase over max. 60 mm. Quantitative determination by multi-wavelength scan in absorbance mode at 252, 262, 316 nm and fluorescence measurement at 366/>400 nm. Polynomial evaluation via peak area and height. Limit of quantitation is between 1-45 ng absolute on the plate. Online coupling with MS by use of a new extractor developed by Luftmann.

Rapid Commun. Mass Sp. 19, 3659-3655 (2005). HPTLC of a preparation of neutral Stx1-binding glycosphingolipids from human erythrocytes, comprising 21.4 % and 59.1 % of the high-and low-affinity Stx1-binding ligands Gb3Cer/CD77 and Gb4Cer respectively and their antibody positive bands on silica gel with chloroform – methanol – water 15:30:4. Crude extracts were used without any further purification for an analysis by nanoelectrospray ionization quadrupole time-of-flight mass spectrometry in the negative mode. Only analytical quantities in the microgram scale of a single glycosphingolipid species are required for the structural MS characterization.

CBS 97, 2-5 (2006). HPTLC of gangliosides on silica gel with chloroform - methanol - water 24:17:4 and addition of 2 mM CaCl2, after chamber saturation with filter paper for 3 h, over 80 mm, followed by drying for 5 min at room temperature. Detection by dipping in orcin solution (0.3 % (w/v) in 3 M H2SO4) followed by heating at 100 °C for 3 min. Alternative detection of GM3-bands by derivatization with primulin (0.02 % (w/v) in aceton - water 4:1). Quantitative determination by direct IR-MALDI-o-TOF-analysis. The limit of detection for GM3 was about 50 ng/zone.

CBS 102, 2-3 (2009). A semi-automatic interface for hyphenation of TLC with mass spectrometry, which was based on the ChromeXtractor by Luftmann, is introduced. The interface is connected to a HPLC pump and the MS. By means of an extraction piston any target zone can be eluted from a TLC/HPTLC plate directly into the MS. Example: for identification of the zone at hRf 15 in a standard mixture of caffeine, paracetamol, and acetylsalicylic acid the mass spectrum of the zone is recorded. After subtraction of a background spectrum a mass spectrum free from system peaks is obtained, which shows mainly substance signals - here the mass signal m/z 195 [M+H]+ for caffeine.

Rapid Commun. Mass Spectrom. 23, 2711-2723 (2009). HPTLC in combination with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was used for the analysis of complex lipid mixtures. For the separation of lipids one-dimensional HPTLC on silica gel aluminum foil was used with a two-phase mobile phase. The combination with MALDI-MS allowed the identification of 70 distinct lipid species and the analysis of even minor lipid classes from only very small volumes of human plasma (50 µL).

Phytochem. Anal. 24, 47-52 (2013) TLC of 22 acylated phenolic compounds on silica gel with acetonitrile - water - chloroform - formic acid 12:3:2:1, followed by dipping into 0.2 % methanolic 2,2-diphenyl-1-picrylhdrazyl solution (DPPH radical reagent) for 5 s and kept in the dark for 30 min. Free radical scavenging activity of the acylated phenolic compounds was assessed by coupling with the image processing software ImageJ .

J. Ethnopharmacol. 158, 487-494 (2014). The review described special techniques such as DNA fingerprinting, nuclear magnetic resonance, near infra red and (bio)sensors that combined with chromatographic techniques provide complementary analytical methods able to give rapid analysis responses, to operate directly on complex matrices, to be portable and to have fast analysis times. TLC is mentioned in the identification section, HPTLC is mentioned in the test for aristolochic acids in herbal drugs.

Trends Anal. Chem. 85, 75-84 (2016). This review describes different approaches for characterization of fossil resins (including amber and all their various types), including chromatographic methods and the application of TLC for separation and purification of compounds and its coupling with mass spectrometry. Fossil resins are often adulterated with modern resins and some rare and precious fossil resin specimens are imitated by more abundant, cheaper fossil specimen (for example succinite – Baltic amber is often imitated by copal).