Waters Atmospheric Pressure GC (APGC) adds GC capability to today’s advanced MS technologies. This provides users with access to ultra-trace quantification, comprehensive qualitative MS and MS/MS, and high resolution, ion-mobility separations. ‘Soft’ ionization means less fragmentation for many compounds compared with techniques such as EI. This can yield higher sensitivity and specificity, simplifying precursor ion selection. Changeover from UPLC to GC is fast and easy and since APGC is not a vacuum technique, equilibration time between modes of operation is kept to a minimum. APGC tandem quadrupole MS, using Waters Xevo TQ-S, enables detection limits at ultra-trace levels.