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www.atmos-meas-tech-discuss.net/3/1133/2010/
doi:10.5194/amtd-3-1133-2010
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Chemical ionization mass spectrometer (CIMS) for ambient measurements of ammonia
1Kent State University, Department of Chemistry, Kent, Ohio, USA
2Kent State University, Department of Computer Sciences, Kent, Ohio, USA
Abstract. This study describes a chemical ionization mass spectrometer (CIMS) for fast response, in-situ measurements for gas phase ammonia. Protonated ethanol ions were used as the ion-molecule reaction reagent. The CIMS sensitivity was estimated to be between 4–25 Hz/pptv with 30% uncertainty. The instrument background was below 1 ppbv and at lowest was 300 pptv. The uncertainty associated with the instrumental background was less than 30 pptv under the optimized experimental conditions. The time response was less than 30 s, and the detection limit was approximately 60 pptv. This CIMS was used to measure the ambient NH3 in Kent, Ohio, for several weeks throughout three seasons. The measured ammonia mixing ratios were usually at the sub-ppbv level, and higher during the spring (200±120 pptv) than in the winter (60±75 pptv) and fall (150±80 pptv).
Discussion Paper (PDF, 3191 KB) Interactive Discussion (Closed, 6 Comments) Final Revised Paper (AMT)
Notice on Discussion StatusCitation: Benson, D. R., Al-Refai, M., and Lee, S.-H.: Chemical ionization mass spectrometer (CIMS) for ambient measurements of ammonia, Atmos. Meas. Tech. Discuss., 3, 1133-1162, doi:10.5194/amtd-3-1133-2010, 2010. Bibtex EndNote Reference Manager XML
