Microsecond-pulsed Glow Discharge Time-of-flight Mass Spectrometry: Analytical Advantages

A microsecond-pulsed glow discharge time-of-flight mass spectrometer was constructed and evaluated for elemental analysis. Mass spectra from the instrument show significant advantages, including higher signal-to-noise ratios than those of a dc glow discharge source. Important temporal advantages result from the pulsed discharge and pulsed mass analyser. Mass discrimination among different elements is very small. The instrument currently has a resolving power of 360 in linear mode and 1600 in reflectron mode (full width at half maximum). Present detection limits are at the low ppm level, limited primarily by the detection and data acquisition system. Because the detector is easily saturated, the present data acquisition system has limited dynamic range and sensitivity. Possibilities exist to overcome this constraint.