Factors influencing ion signal profiles in pulsed glow discharge mass spectrometry

Abstract

Ionization mechanisms responsible for the formation of prepeaks and afterpeaks on Ion signals observed In pulsed glow discharges and potential analytical use of pulsed glow-discharge mass spectrometry have been investigated. The formation of a prepeak at the beginning of the pulse Is related to the Ionization efficiency of electrons accelerated across the cathode fall region. The appearance of an afterpeak at the termination of the discharge is associated with the energy, population, and Ionization efficiency of metastable discharge gas atoms. As a result of the differences In pulse profiles, It Is possible to acquire data over specific regions of the pulse that permit discrimination against Interfering signals In the mass spectrum.

A comparison of non-pulsed radiofrequency and pulsed radiofrequency glow discharge orthogonal time-of-flight mass spectrometry for analytical purposes

“…In our pulsed RF system it is also possible to use the GD source time resolution to further separate analyte ions from polyatomic and discharge gas species because they are formed at different temporal and spatial locations. 20,21 For instance, Fig. 5a shows the mass spectrum interval between 27.…”

Powering the analytical glow discharge

“…One method of extending glow discharges to higher power levels is by the use of pulse techniques. We first used pulsed glow discharges over 20 years ago [18] and have continued the studies in a variety of experiments [19,20]. The principle of plasma enhancement through pulsed methods is easily seen in Fig.…”

“…We have used pulses in the millisecond regime and found a useful sputter enhancement [19], but that effect alone is not necessarily sufficient to justify a pulsed power supply and gated detection system. More interesting has been the temporal advantage [20,21] to be gained, by which certain interference species may be discriminated against.…”

Microsecond-pulse glow discharge atomic emission

“…The glow discharge has been powered by dc [10], rf [11], and pulsed [12] sources. Each has certain advantages, as detailed in relevant reviews.…”