Space Charge Evaluation in a Plasma-Source Mass Spectrograph

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• 作者：Thomas W. Burgoyne ; Gary M. Hieftje ; and Ronald A. Hites
• 刊名：Analytical Chemistry
• 出版年：1997
• 出版时间：February 1, 1997
• 年：1997
• 卷：69
• 期：3
• 页码：485 - 489
• 全文大小：115K
• 年卷期：v.69,no.3(February 1, 1997)
• ISSN：1520-6882

文摘

Space charge effects, and the matrix interferences theycause, are problems in inductively coupled plasma massspectrometry (ICPMS). It has previously been observedthat these deleterious space charge effects are notsignificantly present in sector-field instruments, a fact that hasbeen attributed, but not demonstrated, to the high accelerating potentials they commonly employ. To examinethe significance of space charge in our plasma-sourcemass spectrograph (which operates at only moderateaccelerating potentials) and in other sector instruments,a graphite disk was placed ~7 cm behind the skimmer.An inductively coupled plasma was operated for 17 hwhile a 0.01 mM multielement solution was introduced.This disk was then analyzed by spatially resolvedlaserablation ICP time-of-flight MS. Second vacuum-stageacceleration appears to be an important factor that governs the elemental distribution within the ion beam.Theion beam width at m/z 208 is one-third of its width atm/z7 using an accelerating potential of 800 V; at anaccelerating potential of 4000 V, the ion beam width does not varywith mass.