analyzing spartan filters with an aerosol mass spectrometer rachel o’brien, kelsey ridley, jesse...
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Analyzing SPARTAN filters with an Aerosol Mass Spectrometer
Rachel O’Brien, Kelsey Ridley, Jesse KrollDepartment of Civil and Environmental Engineering, MIT
Manjula Canagaratna, John Jayne, Philip Croteau,Aerodyne Research, Inc.
June 9, 2015
High Resolution-TOF-AMS
• Aerosol Mass Spectrometer with a Time of Flight mass spectrometer• Measure refractory aerosol species • Resolution ~ 2-3k m/Dm
AMS studies worldwide… costly deployment, few long term data sets
Zhang et al., 2007organic sulfate nitrate ammonium
Filters and off-line analysis
• Global filter networks long term data sets, lower deployment cost, more remote and difficult locations
• Filter extracts small sample volumes
Small Volume Nebulizer (SVN) design
Minimum concentration ~0.15 g L-1 (20-30 mg into ~100 mL to be above LOD)
Clean house air
Kapton Polyimide film
AMS
Ultrasonic transducer
Good correlation with commercial atomizer
TSI Atomizer
SVN
TSI Atomizer
SVN
Inter-instrument comparison
0.0001
0.001
0.01
0.1
Onl
ine
aero
sol m
ass
spec
trum
(ion
sign
al n
orm
aliz
ed to
1)
0.0001 0.001 0.01 0.1
Offline aerosol mass spectrum(ion signal normalized to 1)
13
24
25
26
27
30
3738
41
42
4344
45
48
49
5051
52
53
54
55
56
5758
59
60
61
6263
6465
66
6768
697071
7273
74
75
76
77
78
79
80
81
82
83
8485
86
87
8889
90
91
92
9394
9596
979899100
101
102
103104
10516
17
18
15
29
31
Filter extract (AMS)Fi
lter e
xtra
ct (A
CSM
)m/z
Nor
mal
ize re
lativ
e in
tens
ity
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0.00
10080604020
0.15
0.10
0.05
0.00
10080604020
ACSM
AMS
0.10
0.08
0.06
0.04
0.02
0.00
Nitr
ate
equi
vale
nt m
ass
µg/
m3
*
10080604020m/z
HR-MS from Bandung, Indonesia: August 19-20, 2014
OrgSO4
NO3
NH4
O/C = 0.6Org/SO4 = ~6
Future development
• Continuous injection• Add automation, improve sensitivity
• Addition of internal standard • Mass quantification
• Orthogonal analyses– UV/Vis, fluorescence, etc.
Syringe pump
AMS
Conclusions
• The SVN can be used to generate AMS spectra from SPARTAN filters:
• Ensemble organic composition, O/C• Need > 20-30 mg of sample• Extract filters in water
• Ongoing development to improve utility of the SVN:• Quantification• Increased sensitivity• Orthogonal analyses
Acknowledgments
• Kelsey Ridley, Jesse Kroll and the Kroll group
• Manjula Canagaratna, John Jayne, Philip Croteau, and Aerodyne Research, Inc.
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