A thermal-dissociation–cavity ring-down spectrometer (TD-CRDS) for the detection of organic nitrates in gas and particle phases
<p>A thermal-dissociation–cavity ring-down spectrometer (TD-CRDS) was developed to measure <span class="inline-formula">NO<sub>2</sub></span>, peroxy nitrates (PNs), alkyl nitrates (ANs), and <span class="inline-formula">HNO<sub>3</sub...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-11-01
|
| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://amt.copernicus.org/articles/13/6255/2020/amt-13-6255-2020.pdf |
| Summary: | <p>A thermal-dissociation–cavity ring-down spectrometer (TD-CRDS)
was developed to measure <span class="inline-formula">NO<sub>2</sub></span>, peroxy nitrates (PNs), alkyl nitrates
(ANs), and <span class="inline-formula">HNO<sub>3</sub></span> in the gas and particle phase, built using a commercial Los Gatos Research <span class="inline-formula">NO<sub>2</sub></span> analyzer. The detection limit of the TD-CRDS is 0.66 ppb for ANs, PNs, and <span class="inline-formula">HNO<sub>3</sub></span> and 0.48 ppb for <span class="inline-formula">NO<sub>2</sub></span>. For all four classes of <span class="inline-formula">NO<sub><i>y</i></sub></span>, the time resolution for separate gas and particle measurements is 8 min, and for total gas <span class="inline-formula">+</span> particle measurements it is 3 min. The accuracy of the TD-CRDS was tested by comparison of <span class="inline-formula">NO<sub>2</sub></span> measurements with a chemiluminescent <span class="inline-formula">NO<sub><i>x</i></sub></span> monitor and aerosol-phase ANs with
an aerosol mass spectrometer (AMS). <span class="inline-formula">N<sub>2</sub>O<sub>5</sub></span> causes significant
interference in the PN and AN channel under high oxidant concentration
chamber conditions, and ozone pyrolysis causes a negative interference in
the <span class="inline-formula">HNO<sub>3</sub></span> channel. Both interferences can be quantified and corrected for but must be considered when using TD techniques for measurements of organic nitrates. This instrument has been successfully deployed for chamber measurements at widely varying concentrations, as well as ambient measurements of <span class="inline-formula">NO<sub><i>y</i></sub></span>.</p> |
|---|---|
| ISSN: | 1867-1381 1867-8548 |