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Gas Exchange Device (GED) was integrated with Inductively Coupled Plasma Mass Spectrometry(ICP-MS) for analysis of metallic particles in NH3 and HCl gases used in semiconductormanufacturing. A single pg/kg (ppq) level of metallic impurities in these gases could be determinedwithout any sample preparation.

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.

For the first time, direct analysis of gaseous mercury (Hg) at a concentration level of a few ng m−3 in ambient air using the gas to particle conversion-gas exchange technique, coupled with inductively coupled plasma mass spectrometry (ICPMS) has been achieved. Gaseous Hg was converted to mercury oxide (HgO) and agglomerated with ammonium nitrate (NH4NO3) particles by a gas to particle conversion device (GPD). The agglomerates were consequently introduced and measured by ICPMS through a gas exchange device (GED). The time-resolved signals from gaseous Hg in ambient air could be obtained by GPD–GED–ICPMS with a 10 ms dwell time for ICPMS, which demonstrated the real-time monitoring of gaseous Hg with high temporal resolution. No sample pretreatment procedures such as pre-concentration or separation of gaseous Hg from air, were needed before the introduction of gaseous Hg into GPD–GED–ICPMS. Longer dwell times of the ICPMS, such as 100 ms, 500 ms and 1000 ms revealed more stable time-resolved signals. A limit of detection (LOD) for gaseous Hg from the calibration curve was estimated to be ca. 0.12 ng m−3 when a longer dwell time of 1000 ms was selected. Since the LOD observed was sufficiently low compared to the background concentration level of ca. 2 ng m−3 in Japan, the GPD–GED–ICPMS technique is expected to be used for highly sensitive, direct and real-time monitoring of gaseous Hg in ambient air as well as for working and living environments.

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.

An inductively coupled plasma mass spectrometry (ICPMS) coupled with gas to particle conversion-gas exchange technique was applied to the direct analysis of ultra-trace semiconductor gas in ambient air. The ultra-trace semiconductor gases such as arsine (AsH3) and phosphine (PH3) were converted to particles by reaction with ozone (O3) and ammonia (NH3) gases within a gas to particle conversion device (GPD). The converted particles were directly introduced and measured by ICPMS through a gas exchange device (GED), which could penetrate the particles as well as exchange to Ar from either non-reacted gases such as an air or remaining gases of O3 and NH3. The particle size distribution of converted particles was measured by scanning mobility particle sizer (SMPS) and the results supported the elucidation of particle agglomeration between the particle converted from semiconductor gas and the particle of ammonium nitrate (NH4NO3) which was produced as major particle in GPD. Stable time-resolved signals from AsH3 and PH3 in air were obtained by GPD-GED-ICPMS with continuous gas introduction; however, the slightly larger fluctuation, which could be due to the ionization fluctuation of particles in ICP, was observed compared to that of metal carbonyl gas in Ar introduced directly into ICPMS. The linear regression lines were obtained and the limits of detection (LODs) of 1.5 pL L(-1) and 2.4 nL L(-1) for AsH3 and PH3, respectively, were estimated. Since these LODs revealed sufficiently lower values than the measurement concentrations required from semiconductor industry such as 0.5 nL L(-1) and 30 nL L(-1) for AsH3 and PH3, respectively, the GPD-GED-ICPMS could be useful for direct and high sensitive analysis of ultra-trace semiconductor gas in air.

A new gas exchange device (Q-GED) that allows a carrier gas flow of 0.8 L min−1 atmospheric air to be exchanged with Ar combined with aerosol entrainment applied to the analysis of large or heterogeneous samples using Laser Ablation (LA) is reported. The exchange of air components with Ar in the Q-GED was tested using GC-TCD and ICPMS. In ICPMS, no change in oxide levels, or gas blanks, was observed, suggesting a complete exchange of air with Ar. Measured sensitivities were in the same range as sensitivities obtained using LA with an Ar atmosphere, however, the sensitivities were approximately 2-fold lower than those obtained when ablating in He. It was demonstrated that particle transport efficiencies can be enhanced when using quasi-closed cell approaches to control and influence the aerosol expansion volume. Therefore, a plume entrainment device was designed and optimized by computational fluid dynamics, produced using rapid prototype printing, and applied to LA-QGED-ICPMS. Quantitative multi-element analysis of various geological glass reference materials is reported using NIST SRM 612 as the external calibration standard, with relative differences to preferred values of less than 15%. No additional temporal signal dispersion was observed when comparing the new setup with closed cell approaches when using the same flow rates. As opposed to the former GED I-type, a higher spatial resolution can be obtained without destructive sample preparation for large-scale stalagmites. In a proof of concept, it was shown that the same concentration variations were detected for closed cell and GED-based approaches in large-scale stalagmites.

Isotope ratio determination in solids sampled in air under atmospheric pressure using laser ablation with direct introduction into an ICPMS was carried out. The results obtained on the metal brass, and two minerals galena and zircon are reported in this manuscript. The samples were ablated in air and the laser-generated aerosol was aspirated into a gas exchange device (GED), where the air was replaced with Ar and transported into a multicollector-inductively coupled plasma mass spectrometer (MC-ICPMS). To demonstrate the capability of this sampling method, the results were compared to the results obtained using conventional laser ablation (LA)-MC-ICPMS in helium in a sealed cell. Data show that comparable in-run (0.03–1.61%) and external (0.002–0.254%) precisions can be obtained. The accuracy (0.000–0.192%) of both methods was also comparable. However, the atmospheric sampling method gave lower intensities, by up to a factor of 5. Visualization of the aerosol extraction indicates that some material was lost prior to gas exchange. However, this method is suitable for isotopic determination of bulk materials for samples which are too large to fit into an ablation cell or too valuable to be cut into smaller pieces.

An atmospheric sampling approach for LA-ICP-MS is reported. Laser ablation sampling of various materials (gold, brass, and alloys) was carried out in ambient air without using a closed or any ablation cell. The laser generated aerosol containing air was directly sucked into a transport tube and transported towards the ICP-MS by a diaphragm pump. In front of the ICP, air was efficiently exchanged to argon by means of a gas exchange device recently developed for direct analysis of airborne particles by ICP-MS (Nishiguchi et al., J. Anal. At. Spectrom., 2008, 23, 1125). After exchanging air to argon, oxide formation, count rates of the gas blank and potential spectral interferences caused by polyatomic ions on most m/z ratios were found to be similar or lower in comparison to helium exchanged by argon, which indicates a complete exchange of air by argon. LA-ICP-MS analysis of various metallic samples under atmospheric conditions provided results with similar accuracy as commonly achieved with closed transport systems. The implementation of such a gas exchange device will open new applications, especially for objects difficult to place inside an ablation cell, such as archeological samples.

We used a differential mobility analyzer, an aerosol particle mass analyzer, and a gas exchange device to continuously introduce airborne nanoparticles (ANPs) to an inductively coupled plasma mass spectrometer. Pb concentrations in single ANPs with a diameter of 90 nm and a mass of 0.458 fg (density is 1.20 g cm−3) were determined. The developed method enabled us to determine Pb in ANPs having a Pb content of more than 10%.

The real-time multielement monitoring of airborne particulate matter (APM) was carried out using an inductively coupled plasma mass spectrometry (ICP-MS) instrument equipped with a newly developed gas converter apparatus. By using the gas converter apparatus, gas molecules in the air sample and Ar molecules were almost completely exchanged and the gas-converted air sample could be directly introduced into ICP-MS instruments. Fe in clean room and outdoor air samples was directly measured using the ICP-MS instrument equipped with the converter apparatus. The signal intensities of Be, Ag, Cd, Sn, Sb, Tl, Pb, Bi, Th, and U in the outdoor air sample were successfully measured at every 8 min for 77 h.