Open AccessA comparison of particle mass spectrometers during the 1999 Atlanta Supersite Project
Author(s) -
Middlebrook Ann M.,
Murphy Daniel M.,
Lee ShanHu,
Thomson David S.,
Prather Kimberly A.,
Wenzel Ryan J.,
Liu DonYuan,
Phares Denis J.,
Rhoads Kevin P.,
Wexler Anthony S.,
Johnston Murray V.,
Jimenez José L.,
Jayne John T.,
Worsnop Douglas R.,
Yourshaw Ivan,
Seinfeld John H.,
Flagan Richard C.
Publication year - 2003
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2001jd000660
Subject(s) - mass spectrometry , spectrometer , aerosol , ionization , laser , particle (ecology) , analytical chemistry (journal) , materials science , chemistry , ion , optics , physics , chromatography , geology , oceanography , organic chemistry
During the Atlanta Supersite Project, four particle mass spectrometers were operated together for the first time: NOAA's Particle Analysis by Laser Mass Spectrometer (PALMS), University of California at Riverside's Aerosol Time‐of‐Flight Mass Spectrometer (ATOFMS), University of Delaware's Rapid Single‐Particle Mass Spectrometer II (RSMS‐II), and Aerodyne's Aerosol Mass Spectrometer (AMS). Although these mass spectrometers are generally classified as similar instruments, they clearly have different characteristics due to their unique designs. One primary difference is related to the volatilization/ionization method: PALMS, ATOFMS, and RSMS‐II utilize laser desorption/ionization, whereas particles in the AMS instrument are volatilized by impaction onto a heated surface with the resulting components ionized by electron impact. Thus mass spectral data from the AMS are representative of the ensemble of particles sampled, and those from the laser‐based instruments are representative of individual particles. In addition, the AMS instrument cannot analyze refractory material such as soot, sodium chloride, and crustal elements, and some sulfate or water‐rich particles may not always be analyzed with every laser‐based instrument. A main difference among the laser‐based mass spectrometers is that the RSMS‐II instrument can obtain size‐resolved single particle composition information for particles with aerodynamic diameters as small as 15 nm. The minimum sizes analyzed by ATOFMS and PALMS are 0.2 and about 0.35 μm, respectively, in aerodynamic diameter. Furthermore, PALMS, ATOFMS, and RSMS‐II use different laser ionization conditions. Despite these differences the laser‐based instruments found similar individual particle classifications, and their relative fractions among comparable sized particles from Atlanta were broadly consistent. Finally, the AMS measurements of the nitrate/sulfate mole ratio were highly correlated with composite measurements (r 2 = 0.93). In contrast, the PALMS nitrate/sulfate ion ratios were only moderately correlated (r 2 ∼ 0.7).