Characterisation of an inlet pre-injector laser-induced fluorescence instrument for the measurement of atmospheric hydroxyl radicals
Atmospheric measurements of hydroxyl radicals (OH) are challenging due to a high reactivity and consequently low concentration. The importance of OH as an atmospheric oxidant has motivated a sustained effort leading to the development of a number of highly sensitive analytical techniques. Recent wor...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2014-10-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | http://www.atmos-meas-tech.net/7/3413/2014/amt-7-3413-2014.pdf |
| _version_ | 1811316819626033152 |
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| author | A. Novelli K. Hens C. Tatum Ernest D. Kubistin E. Regelin T. Elste C. Plass-Dülmer M. Martinez J. Lelieveld H. Harder |
| author_facet | A. Novelli K. Hens C. Tatum Ernest D. Kubistin E. Regelin T. Elste C. Plass-Dülmer M. Martinez J. Lelieveld H. Harder |
| author_sort | A. Novelli |
| collection | DOAJ |
| description | Atmospheric measurements of hydroxyl radicals (OH) are challenging due to a
high reactivity and consequently low concentration. The importance of OH as
an atmospheric oxidant has motivated a sustained effort leading to the
development of a number of highly sensitive analytical techniques. Recent
work has indicated that the laser-induced fluorescence of the OH molecules
method based on the fluorescence assay by gas expansion technique (LIF-FAGE)
for the measurement of atmospheric OH in some environments may be influenced
by artificial OH generated within the instrument, and a chemical method to
remove this interference was implemented in a LIF-FAGE system by Mao et al. (2012). While it
is not clear whether other LIF-FAGE instruments suffer from the same
interference, we have applied this method to our LIF-FAGE HORUS (Hydroxyl
Radical Measurement Unit based on fluorescence Spectroscopy) system, and
developed and deployed an inlet pre-injector (IPI) to determine the chemical
zero level in the instrument via scavenging the ambient OH radical.
<br><br>
We describe and characterise this technique in addition to its application
at field sites in forested locations in Finland, Spain and Germany. Ambient
measurements show that OH generated within the HORUS instrument is a
non-negligible fraction of the total OH signal, which can comprise 30 to
80% during daytime and 60 to 100% during the night. The
contribution of the background OH varied greatly between measurement sites
and was likely related to the type and concentration of volatile organic
compounds (VOCs) present at each particular location. Two inter-comparisons
in contrasting environments between the HORUS instrument and two different
chemical ionisation mass spectrometers (CIMS) are described to demonstrate
the efficacy of IPI and the necessity of the chemical zeroing method for our
LIF-FAGE instrument in such environments. |
| first_indexed | 2024-04-13T11:55:59Z |
| format | Article |
| id | doaj.art-97bd914361ef46808a0bc3153a3826e9 |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-04-13T11:55:59Z |
| publishDate | 2014-10-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-97bd914361ef46808a0bc3153a3826e92022-12-22T02:47:55ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482014-10-017103413343010.5194/amt-7-3413-2014Characterisation of an inlet pre-injector laser-induced fluorescence instrument for the measurement of atmospheric hydroxyl radicalsA. Novelli0K. Hens1C. Tatum Ernest2D. Kubistin3E. Regelin4T. Elste5C. Plass-Dülmer6M. Martinez7J. Lelieveld8H. Harder9Atmospheric Chemistry Dept., Max Planck Institute for Chemistry, 55128 Mainz, GermanyAtmospheric Chemistry Dept., Max Planck Institute for Chemistry, 55128 Mainz, GermanyAtmospheric Chemistry Dept., Max Planck Institute for Chemistry, 55128 Mainz, GermanyAtmospheric Chemistry Dept., Max Planck Institute for Chemistry, 55128 Mainz, GermanyAtmospheric Chemistry Dept., Max Planck Institute for Chemistry, 55128 Mainz, GermanyGerman Weather Service, Meteorological Observatory Hohenpeissenberg (MOHp), Albin-Schwaiger-Weg 10, 83282 Hohenpeissenberg, GermanyGerman Weather Service, Meteorological Observatory Hohenpeissenberg (MOHp), Albin-Schwaiger-Weg 10, 83282 Hohenpeissenberg, GermanyAtmospheric Chemistry Dept., Max Planck Institute for Chemistry, 55128 Mainz, GermanyAtmospheric Chemistry Dept., Max Planck Institute for Chemistry, 55128 Mainz, GermanyAtmospheric Chemistry Dept., Max Planck Institute for Chemistry, 55128 Mainz, GermanyAtmospheric measurements of hydroxyl radicals (OH) are challenging due to a high reactivity and consequently low concentration. The importance of OH as an atmospheric oxidant has motivated a sustained effort leading to the development of a number of highly sensitive analytical techniques. Recent work has indicated that the laser-induced fluorescence of the OH molecules method based on the fluorescence assay by gas expansion technique (LIF-FAGE) for the measurement of atmospheric OH in some environments may be influenced by artificial OH generated within the instrument, and a chemical method to remove this interference was implemented in a LIF-FAGE system by Mao et al. (2012). While it is not clear whether other LIF-FAGE instruments suffer from the same interference, we have applied this method to our LIF-FAGE HORUS (Hydroxyl Radical Measurement Unit based on fluorescence Spectroscopy) system, and developed and deployed an inlet pre-injector (IPI) to determine the chemical zero level in the instrument via scavenging the ambient OH radical. <br><br> We describe and characterise this technique in addition to its application at field sites in forested locations in Finland, Spain and Germany. Ambient measurements show that OH generated within the HORUS instrument is a non-negligible fraction of the total OH signal, which can comprise 30 to 80% during daytime and 60 to 100% during the night. The contribution of the background OH varied greatly between measurement sites and was likely related to the type and concentration of volatile organic compounds (VOCs) present at each particular location. Two inter-comparisons in contrasting environments between the HORUS instrument and two different chemical ionisation mass spectrometers (CIMS) are described to demonstrate the efficacy of IPI and the necessity of the chemical zeroing method for our LIF-FAGE instrument in such environments.http://www.atmos-meas-tech.net/7/3413/2014/amt-7-3413-2014.pdf |
| spellingShingle | A. Novelli K. Hens C. Tatum Ernest D. Kubistin E. Regelin T. Elste C. Plass-Dülmer M. Martinez J. Lelieveld H. Harder Characterisation of an inlet pre-injector laser-induced fluorescence instrument for the measurement of atmospheric hydroxyl radicals Atmospheric Measurement Techniques |
| title | Characterisation of an inlet pre-injector laser-induced fluorescence instrument for the measurement of atmospheric hydroxyl radicals |
| title_full | Characterisation of an inlet pre-injector laser-induced fluorescence instrument for the measurement of atmospheric hydroxyl radicals |
| title_fullStr | Characterisation of an inlet pre-injector laser-induced fluorescence instrument for the measurement of atmospheric hydroxyl radicals |
| title_full_unstemmed | Characterisation of an inlet pre-injector laser-induced fluorescence instrument for the measurement of atmospheric hydroxyl radicals |
| title_short | Characterisation of an inlet pre-injector laser-induced fluorescence instrument for the measurement of atmospheric hydroxyl radicals |
| title_sort | characterisation of an inlet pre injector laser induced fluorescence instrument for the measurement of atmospheric hydroxyl radicals |
| url | http://www.atmos-meas-tech.net/7/3413/2014/amt-7-3413-2014.pdf |
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