TLC/HPTLC with direct mass spectrometric detection: A review of the progress achieved in the last 5 years

Abstract

Thin-layer chromatography (TLC) is a widely used, fast and inexpensive method. Even minor constituents of complex mixtures can be often characterized. Unfortunately, the unambiguous assignment of the spots to defined compounds is often difficult because common staining methods normally reveal only (at best) a substance class, not a specific compound. For instance, in the case of phospholipids, the lipid class, but not the detailed fatty acyl composition, can be determined (normal phase TLC). Nowadays mass spectrometry (MS) seems to be the most suitable method for analyte characterization due to its high sensitivity and mass accuracy. This became possible by the invention of soft ionization methods such as matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) MS and electrospray ionization (ESI) although many further desorption techniques are available nowadays. This review summarizes the so far available knowledge about direct TLC/MS couplings and gives an overview about selected compounds that could be successfully analyzed. © 2011 Springer-Verlag Berlin Heidelberg.