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| Titel |
Development and characterization of a single particle laser ablation mass spectrometer (SPLAM) for organic aerosol studies |
| VerfasserIn |
F. Gaie-Levrel, S. Perrier, E. Perraudin, C. Stoll, N. Grand, M. Schwell |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 5, no. 1 ; Nr. 5, no. 1 (2012-01-26), S.225-241 |
| Datensatznummer |
250002318
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| Publikation (Nr.) |
 copernicus.org/amt-5-225-2012.pdf |
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| Zusammenfassung |
| A single particle instrument was developed for real-time analysis of organic
aerosol. This instrument, named Single Particle Laser Ablation Mass
Spectrometry (SPLAM), samples particles using an aerodynamic lens system for
which the theoretical performances were calculated. At the outlet of this
system, particle detection and sizing are realized by using two continuous
diode lasers operating at λ = 403 nm. Polystyrene Latex (PSL),
sodium chloride (NaCl) and dioctylphtalate (DOP) particles were used to
characterize and calibrate optical detection of SPLAM. The optical detection
limit (DL) and detection efficiency (DE) were determined using size-selected
DOP particles. The DE ranges from 0.1 to 90% for 100 and 350 nm DOP
particles respectively and the SPLAM instrument is able to detect and
size-resolve particles as small as 110–120 nm. During optical detection,
particle scattered light from the two diode lasers, is detected by two
photomultipliers and the detected signals are used to trigger UV excimer
laser (λ = 248 nm) used for one-step laser desorption ionization
(LDI) of individual aerosol particles. The formed ions are analyzed by a 1 m
linear time-of-flight mass spectrometer in order to access to the chemical
composition of individual particles. The TOF-MS detection limit for gaseous
aromatic compounds was determined to be 0.85 × 10−15 kg
(∼4 × 103 molecules). DOP particles were also used to test the overall operation of
the instrument. The analysis of a secondary organic aerosol, formed in a
smog chamber by the ozonolysis of indene, is presented as a first
application of the instrument. Single particle mass spectra were obtained
with an effective hit rate of 8%. Some of these mass spectra were found
to be very different from one particle to another possibly reflecting
chemical differences within the investigated indene SOA particles. Our study
shows that an exhaustive statistical analysis, over hundreds of particles,
and adapted reference mass spectra are further needed to understand the
chemical meaning of single particle mass spectra of chemically complex
submicrometer-sized organic aerosols. |
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