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Production of neutral molecular clusters by controlled neutralization of mobility standards
Measuring aerosols and molecular clusters below the 3 nm size limit is essential to increase our understanding of new particle formation. Instruments for the detection of sub-3 nm aerosols and clusters exist and need to be carefully calibrated and characterized. So far calibrations and laboratory te...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Taylor & Francis
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5546065/ https://www.ncbi.nlm.nih.gov/pubmed/28824221 http://dx.doi.org/10.1080/02786826.2017.1328103 |
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author | Steiner, G. Franchin, A. Kangasluoma, J. Kerminen, V.-M. Kulmala, M. Petäjä, T. |
author_facet | Steiner, G. Franchin, A. Kangasluoma, J. Kerminen, V.-M. Kulmala, M. Petäjä, T. |
author_sort | Steiner, G. |
collection | PubMed |
description | Measuring aerosols and molecular clusters below the 3 nm size limit is essential to increase our understanding of new particle formation. Instruments for the detection of sub-3 nm aerosols and clusters exist and need to be carefully calibrated and characterized. So far calibrations and laboratory tests have been carried out using mainly electrically charged aerosols, as they are easier to handle experimentally. However, the charging state of the cluster is an important variable to take into account. Furthermore, instrument characterization performed with charged aerosols could be biased, preventing a correct interpretation of data when electrically neutral sub-3 nm aerosols are involved. This article presents the first steps to generate electrically neutral molecular clusters as standards for calibration. We show two methods: One based on the neutralization of well-known molecular clusters (mobility standards) by ions generated in a switchable aerosol neutralizer. The second is based on the controlled neutralization of mobility standards with mobility standards of opposite polarity in a recombination cell. We highlight the challenges of these two techniques and, where possible, point out solutions. In addition, we give an outlook on the next steps toward generating well-defined neutral molecular clusters with a known chemical composition and concentration. Published with license by American Association for Aerosol Research |
format | Online Article Text |
id | pubmed-5546065 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | Taylor & Francis |
record_format | MEDLINE/PubMed |
spelling | pubmed-55460652017-08-17 Production of neutral molecular clusters by controlled neutralization of mobility standards Steiner, G. Franchin, A. Kangasluoma, J. Kerminen, V.-M. Kulmala, M. Petäjä, T. Aerosol Sci Technol Articles Measuring aerosols and molecular clusters below the 3 nm size limit is essential to increase our understanding of new particle formation. Instruments for the detection of sub-3 nm aerosols and clusters exist and need to be carefully calibrated and characterized. So far calibrations and laboratory tests have been carried out using mainly electrically charged aerosols, as they are easier to handle experimentally. However, the charging state of the cluster is an important variable to take into account. Furthermore, instrument characterization performed with charged aerosols could be biased, preventing a correct interpretation of data when electrically neutral sub-3 nm aerosols are involved. This article presents the first steps to generate electrically neutral molecular clusters as standards for calibration. We show two methods: One based on the neutralization of well-known molecular clusters (mobility standards) by ions generated in a switchable aerosol neutralizer. The second is based on the controlled neutralization of mobility standards with mobility standards of opposite polarity in a recombination cell. We highlight the challenges of these two techniques and, where possible, point out solutions. In addition, we give an outlook on the next steps toward generating well-defined neutral molecular clusters with a known chemical composition and concentration. Published with license by American Association for Aerosol Research Taylor & Francis 2017-08-03 2017-05-08 /pmc/articles/PMC5546065/ /pubmed/28824221 http://dx.doi.org/10.1080/02786826.2017.1328103 Text en © 2017 The Author(s). Published with license by American Association for Aerosol Research This is an Open Access article. Non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly attributed, cited, and is not altered, transformed, or built upon in any way, is permitted. The moral rights of the named author(s) have been asserted. |
spellingShingle | Articles Steiner, G. Franchin, A. Kangasluoma, J. Kerminen, V.-M. Kulmala, M. Petäjä, T. Production of neutral molecular clusters by controlled neutralization of mobility standards |
title | Production of neutral molecular clusters by controlled neutralization of mobility standards |
title_full | Production of neutral molecular clusters by controlled neutralization of mobility standards |
title_fullStr | Production of neutral molecular clusters by controlled neutralization of mobility standards |
title_full_unstemmed | Production of neutral molecular clusters by controlled neutralization of mobility standards |
title_short | Production of neutral molecular clusters by controlled neutralization of mobility standards |
title_sort | production of neutral molecular clusters by controlled neutralization of mobility standards |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5546065/ https://www.ncbi.nlm.nih.gov/pubmed/28824221 http://dx.doi.org/10.1080/02786826.2017.1328103 |
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