Gas chromatography/surface-assisted laser desorption ionization mass spectrometry of amphetamine-like compounds

A variety of amphetamine-like compounds were analyzed by gas chromatography/surface-assisted laser desorption ionization mass spectrometry, GC/SALDI-MS. In the SALDI method, compounds are adsorbed on a solid SALDI substrate and directly ionized from the substrate by means of a laser pulse. The interfacing of a SALDI ion source with a gas chromatograph is presented here for the first time. The end of the GC column is situated 20 mm from the silicon substrate in the vacuum of the ion source of a time-of-flight mass spectrometer, and the compounds eluted from the GC capillary are adsorbed onto the nanostructured silicon surface. The mass spectra show very low levels of background noise and no reagent ions. GC/SALDI-MS detection limits are several orders of magnitude lower than those previously reported for GC/MS analysis of amphetamine-like compounds. The extent of fragmentation is under experimental control by changing the laser fluence.