Offering fast data acquisition rates and high resolving power the AccuTOF GCv 4G has a maximum data acquisition rate of 50 spectra per second and a resolving power of 8000. The 50 Hz acquisition rate now makes it possible to acquire high-resolution mass spectra in combination with third party two-dimensional GC (GC×GC). This unit is sensitive at S/N >100 at OFN 1 pg/µL. The combination EI/FI/FD ion source offers both molecular weight information (field ionization and field desorption: FI and FD) and classical library-searchable (electron ionization: EI) mass spectra without having to change ion sources. The system is suitable for analyzing complex mixtures of true unknowns, even at low concentrations in environmental samples, petrochemicals, polymers and materials, forensics, foods, flavors, and fragrances.