Gas to Particle Conversion-Gas Exchange Technique for Direct Analysis of Metal Carbonyl Gas by Inductively Coupled Plasma Mass Spectrometry

Abstract

A novel gas to particle conversion-gas exchange technique for the direct analysis of metal carbonyl gas by inductively coupled plasma mass spectrometry (ICPMS) was proposed and demonstrated in the present study. The technique is based on a transfer of gas into particle, which can be directly analyzed by ICPMS. Particles from metal carbonyl gases such as Cr(CO)6, Mo(CO)6, and W(CO)6 are formed by reaction with ozone (O3) and ammonium (NH3) gases within a newly developed gas to particle conversion device (GPD). The reaction mechanism of the gas to particle conversion is based on either oxidation of metal carbonyl gas by O3 or agglomeration of metal oxide with ammonium nitrate (NH4NO3) which is generated by the reaction of O3 and NH3. To separate the reaction gases (remaining O3 and NH3) from the formed particles, a previously reported gas exchange device (GED) was used and the in argon stabilized analyte particles were directly introduced and measured by ICPMS. This new technique provided limits of detection (LOD) of 0.15 pL L(-1) (0.32 ng m(-3)), 0.02 pL L(-1) (0.07 ng m(-3)), and 0.01 pL L(-1) (0.07 ng m(-3)) for Cr(CO)6, Mo(CO)6, and W(CO)6, respectively, which were 4-5 orders of magnitude lower than those conventional applied for detecting these gases, e.g., gas chromatography with electron captured detector (GC-ECD) as well as Fourier transform-infrared spectroscopy (FT-IR). The achieved LODs were also similar or slightly better than those for ICPMS coupled to GC. Since the gas to particle conversion technique can achieve the direct measurement of metal carbonyl gases as well as the removal of reaction and ambient gases from metal carbonyl gases, the technique is considered to be well suited to monitor gas quality in semiconductor industry, engine exhaust gases, and or waste incineration products.

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

“…From the research progress, a gas to particle conversion device (GPD), which could be applied to the gas to particle conversiongas exchange technique for the direct analysis of metallic compound gas by ICP-MS (GPD-GED-ICP-MS), was developed and the working principle, the reaction mechanism and the figures of merit of GPD-GED-ICP-MS have been discussed in our previous studies. [15][16][17][18][19] It is noted that the metallic compound gas as an analytical target should be reactive with respect to O3 gas for gas to particle conversion.…”

“…The reaction mechanism of the gas to particle conversion is based on either the oxidation of metallic compound gas by O3 or the agglomeration of metal oxide with NH4NO3 which is generated by the reaction of O3 and NH3 gases in GPD. [15][16][17][18][19] The oxidation of arsine (AsH3), as an example, by O3 for the gas to particle conversion in the GPD can be considered as follows: 17 2AsH3 (g) + 2O3 (g) ⎯→ As2O3 (s) + 3H2O (l) The NH3 gas supplied was also considered to generate particles of NH4NO3 in the GPD when reacting with O3 as described below.…”

“…4. [16][17][18] Since the technique detects the metallic compound gas directly without any sampling methods, it can be applied to the real-time monitoring.…”

“…The efficiency of the gas to particle conversion of AsH3 was expected to be 50 -60% since the operating conditions of GPD were not sufficient to achieve 100% conversion efficiency compared to those examined for metal carbonyl gases in our previous study. 16 Although either the optimization of operating conditions or the design of reaction chamber of GPD might increase the conversion efficiency and reduce the fluctuation as well as the memory effect, the GPD-GED-ICP-MS could be used for the measurement of trace level of semiconductor gas such as AsH3 in ambient air since RSDs observed sufficiently small.…”

“…In order to achieve the direct measurement of metallic compound gas, a gas to particle conversion-gas exchange technique coupled with ICP-MS (GPD-GED-ICP-MS) was newly proposed and its figures of merit were successfully demonstrated with respect to metallic compound gases such as metal carbonyl gas, semiconductor gas and gaseous mercury (Hg) in our previous studies. [15][16][17][18][19] The reaction mechanism of the gas to particle conversion is based on either the oxidation of metallic compound gas by ozone (O3) or the agglomeration of metal oxide with ammonium nitrate (NH4NO3), which is generated by the reaction of O3 and ammonia (NH3) gases in a gas to particle conversion device (GPD). In order to separate the reaction gases (remaining O3 and NH3) as well as non-reacted gases such as nitrogen (N2), oxygen (O2), carbon dioxide (CO2) in ambient air from the converted particles, GED [3][4][5][6][7][8][9][10][11][12][13][14] was used and the particles in Ar, otherwise ICP cannot be maintained, were directly introduced and measured by ICP-MS.…”