The MALDI tandem time-of-flight mass spectrometer combines the high mass accuracy and resolution of a TOF-analyser with highly specific precursor ion selection for sensitive CID (collision induced dissociation) analysis. Matrix assisted laser desorption/ionization is a robust ionisation method that tolerates certain amounts of additives/contaminations. The 4800 MALDI TOF/TOF-analyzer is able to separate molecules of a wide mass range. Ions of up to 6-8 kDa can be detected in reflector mode and all ions of up to > 100 kDa in linear mode. However mass accuracy and resolution is low in linear mode whereas an accuracy of 5ppm and a resolution of 15000-25000 FWHM (full width at half maximum) are achievable in a mass range of up to 4000 m/z in reflector mode. The effective sensitivity for MS/MS analyses is in the low fmol range.
Offline coupling of MALDI TOF/TOF mass spectrometry with liquid chromatography via automated MALDI-plate spotting of the fractions enables high throughput protein analyses.