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| Titel |
Qualitative and quantitative determination of water in airborne particulate matter |
| VerfasserIn |
S. Canepari, C. Farao, E. Marconi, C. Giovannelli, C. Perrino |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 3 ; Nr. 13, no. 3 (2013-02-01), S.1193-1202 |
| Datensatznummer |
250017624
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| Publikation (Nr.) |
 copernicus.org/acp-13-1193-2013.pdf |
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| Zusammenfassung |
This paper describes the optimization and validation of a new simple method
for the quantitative determination of water in atmospheric particulate
matter (PM). The analyses are performed by using a coulometric Karl-Fisher
system equipped with a controlled heating device; different water
contributions are separated by the application of an optimized thermal ramp
(three heating steps: 50–120 °C, 120–180 °C,
180–250 °C).
The analytical performance of the method was verified by using standard
materials containing 5.55% and 1% by weight of water. The recovery
was greater than 95%; the detection limit was about 20 μg. The
method was then applied to NIST Reference Materials (NIST1649a, urban
particulate matter) and to real PM10 samples collected in different
geographical areas. In all cases the repeatability was satisfactory
(10–15%).
When analyzing the Reference Material, the separation of four different
types of water was obtained. In real PM10 samples the amount of water
and its thermal profile differed as a function of the chemical composition
of the dust. Mass percentages of 3–4% of water were obtained in most
samples, but values up to about 15% were reached in areas where the
chemical composition of PM is dominated by secondary inorganic ions and
organic matter. High percentages of water were also observed in areas where
PM is characterized by the presence of desert dust.
A possible identification of the quality of water released from the samples
was tried by applying the method to some hygroscopic compounds that are
likely contained in PM (pure SiO2, Al2O3, ammonium salts,
carbohydrates and dicarboxylic acids) and by comparing the results with
those obtained from field samples. |
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