HPTLC-MS coupling: New dimension of HPTLC

Abstract

The direct coupling of TLC/HPTLC with mass spectrometry (MS) is of particular interest because of the later's high sensitivity, rapid analysis, and ability to aid structural characterization. The conventional ionization method requires heating of the analyte and was suitable only for the analyses of volatile and thermally stable compounds. In contrast, desorption/ionization (DI) techniques, such as fast atom bombardment (FAB), plasma desorption, laser desorption, and matrix-assisted laser desorption/ionization (MALDI) methods, appear to be better for directly characterizing nonvolatile and thermally labile chemical or biochemical compounds separated by HPTLC. HPTLC-MS is cost-effective because the chromatographic run is decoupled with the detection step. Van Berkel and co-workers introduced a novel TLC-ESI-MS, a surface sampling probe-to-TLC/HPTLC plate liquid microjunction, and a self-aspirating ES emitter for the direct detection of small organic compounds. Luftmann developed a plunger-based extraction device for TLC/HPTLC ESI-MS and used a direct electrospray probe to generate analyte ions directly from the end of a TLC plate. Recently, Van Berkel's group applied desorption electrospray ionization (DESI). Cooks et al. introduced the analysis of analytes on solids for coupling TLC with MS. Due to the great understanding of the subject, thin layer chromatography/high-performance thin-layer chromatography can be used interchangeably for methods developed in the twenty-first century. © 2011 Springer-Verlag Berlin Heidelberg.