Limits of detection and artifact formation of sulfates and nitrates collected with a triple-path denuder
Ammonium sulfate and nitrate aerosols were generated and sampled on Teflon (PTFE) filters in a triple-path denuder (TPD) at the Research Triangle Institute. Lower limits of detection and quantitative analysis of the resulting samples were completed by X-ray diffraction at the South Dakota School of...
Saved in:
Published in | Atmospheric environment (1994) Vol. 28; no. 15; pp. 2485 - 2491 |
---|---|
Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
Elsevier Ltd
01.08.1994
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Ammonium sulfate and nitrate aerosols were generated and sampled on Teflon (PTFE) filters in a triple-path denuder (TPD) at the Research Triangle Institute. Lower limits of detection and quantitative analysis of the resulting samples were completed by X-ray diffraction at the South Dakota School of Mines and Technology. Denuder coatings included oxalic acid for removal of ammonia, and NaCl for capture of nitric acid; a third path was left uncoated. Primary aerosol concentrations of 17 and 79 μg m
−3 for (NH
4)
2SO
4 (mascagnite), and 10 μg m
−3 for NH
4NO
3 were generated by a nebulizer and introduced to the instrument's PM
10 sampling inlet under a Tedlar chamber. Monitoring of generated species during collection at RTI was conducted using ion chromatography. Lower limits of detection (LLD, as wt%) for the sulfate and nitrate collections on the filters varied from 0.9 to (as high as) 22 for extremely light filter loadings. Spalling of the oxalic acid coating along denuder A and contamination of the aerosol in the collection cassette resulted in an initially rapid but decaying rate of artifact reaction of the mascagnite to letovicite (NH
4)
3H(SO
4)
2 over several months of laboratory storage. No analogous reaction was observed for the NH
4NO
3 aerosol samples. |
---|---|
Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 1352-2310 1873-2844 |
DOI: | 10.1016/1352-2310(94)90399-9 |