Modified chromatographic thin layer surface as an interface to couple thin layer chromatography with ToF‐SIMS

Abstract

The goal of our research is the development of a new interface to combine thin layer chromatography (TLC) with time-of-flight secondary ion mass spectrometry (ToF-SIMS). The direct combination of the simple separation technique (TLC) with the highly selective identification unit (ToF-SIMS) requires a modification of common TLC material to reduce the background signal in SIMS spectra. The background signal is caused either by the stationary phase or by the residual mobile phase (solvent). The aluminium back of the TLC layer has been modified to get a universal porous TLC-ToF-SIMS interface. Functionality of this novel interface has been tested with a Methyl Red indicator as a representative analyte to visualize its transport through the chromatographic layer and interface. From ToF-SIMS results it was found that the indicator molecule fragments at the diazo double bond -N N-.

Dielectric Barrier Discharge Ionization in Characterization of Organic Compounds Separated on Thin-Layer Chromatography Plates

“…Desorption/ionization methods that operate under vacuum have been used to obtain mass spectra of compounds directly from the surface of TLC plates. Several techniques such as fast atom bombardment (FAB) [9] , [10] , secondary ion mass spectrometry (SIMS) [11] , laser desorption (LDI) [12] , matrix-assisted laser desorption/ionization (MALDI) [13] , [14] , surface-assisted laser desorption/ionization (SALDI) [15] have been applied to characterize compounds separated by TLC. These techniques however, generate several problems: obtaining high vacuum in the ion source considerably increases the time of analysis, volatile compounds have poor sensitivity, MALDI matrices produce interferences with mass spectra, poor reproducibility in quantitative analysis, diffusion of analytes on TLC plates after applying MALDI matrix solution [16] .…”