Research Progress on Gas to Particle Conversion-Gas Exchange ICP-MS for Direct Analysis of Ultra-trace Metallic Compound Gas.

A novel gas to particle conversion-gas exchange technique coupled with inductively coupled plasma mass spectrometry (GPD-GED-ICP-MS) was recently proposed for the direct analysis of ultra-trace levels of metallic compound gases such as metal carbonyl and semiconductor gases as well as gaseous mercury (Hg) in ambient air. These metallic compound gases should reveal reactivity with respect to ozone and gas to particle conversion could be obtained in a gas to particle conversion device (GPD) through metal oxides by oxidation. The particles converted were separated from non-reactive gases such as nitrogen, oxygen, carbon dioxide in ambient air by a gas exchange device (GED) and the particles in argon, otherwise ICP cannot be maintained, were directly introduced and measured by ICP-MS. Since the technique detects the metallic compound gas directly without any sampling methods, it is expected to be applied to real-time monitoring. This article highlights the research progress and novelty on GPD-GED-ICP-MS for the direct analysis of ultra-trace metallic compound gas. It was also noted that the direct analysis of gaseous Hg at the concentration level of a few ng m-3 in ambient air mentioned in this article was world-first achieved by GPD-GED-ICP-MS. The research progress for multi-element analysis in suspended particulate matter by GED-ICP-MS was also mentioned since the GED was always used for GPD-GED-ICP-MS.