HIGH-SPEED NARROW-BORE CAPILLARY GAS-CHROMATOGRAPHY IN COMBINATION WITH A FAST DOUBLE-FOCUSING MASS-SPECTROMETER

In this work the application of high-speed narrow-bore capillary GC in combination with a fast scanning double focusing magnetic sector mass spectrometer is evaluated, Special emphasis is placed upon detection limits and scan speed in the full scan mode and in the selected ion mo nitoring mode (SIM), In the full scan mode, up to 20 scans per second could be obtained, The detection limits are in the low picogram range in the full scan mode and improve even to 5 to 50 fg in the SIM mode, depending on the sample complexity and mass resolving power, It will b e illustrated that by increasing the resolution in the SIM mode, inter ferences from ions of the same nominal mass-to-charge ratio as the ion s of interest are significantly reduced, Chemical background noise can therefore be largely eliminated, thus enhancing the signal-to-noise r atio.