Evaluation of the new capture vaporizer for aerosol mass spectrometers (AMS) through field studies of inorganic species (original) (raw)
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Journal of Geophysical Research: Atmospheres, 2007
Highly time resolved measurements of nitrate in ambient aerosols were conducted by an Aerodyne Quadrupole Aerosol Mass Spectrometer (Q‐AMS or simply AMS) and a particle‐into‐liquid sampler (PILS) coupled to ion chromatography from field intensives at two sites: an urban site in New York City (Queens College; QC) for wintertime (22 January to 5 February 2004) and a rural site in southwestern New York state (Pinnacle State Park; PSP) for summertime (18 July to 6 August 2004). In this study, we report that in rural atmospheres the inorganic nitrate signal from Q‐AMS may contain significant interferences from organic signals. Analysis of the QC data indicates a good agreement between the PILS‐nitrate and AMS‐nitrate measurements (R2 = 0.94; linear regression slope = 1.05). In addition, the m/z 30 and m/z 46 (two dominant ion fragments in nitrate mass spectrum) signals tightly correlate at QC (R2 = 0.98) and have an average ratio similar to that determined in the laboratory for NH4NO3 (m...
Journal of Geophysical Research, 2003
Abstract[1] The aerosol mass spectrometer (AMS), manufactured by Aerodyne Research, Inc., has been shown to be capable of delivering quantitative information on the chemical composition and size of volatile and semivolatile fine airborne particulate matter with high time resolution. Analytical and software tools for interpreting the data from this instrument and generating meaningful, quantitative results have been developed and are presented here with a brief description of the instrument. These include the conversion of detected ion rates from the quadrupole mass spectrometer during the mass spectrum (MS) mode of operation to atmospheric mass concentrations of chemical species (in μg m−3) by applying calibration data. It is also necessary to correct for variations in the electron multiplier performance, and a method involving the measurement of the instrument's response to gas phase signals is also presented. The techniques for applying particle velocity calibration data and transforming signals from time of flight (TOF) mode to chemical mass distributions in terms of aerodynamic diameter (dM/dlog(Da) distributions) are also presented. It is also possible to quantify the uncertainties in both MS and TOF data by evaluating the ion counting statistics and variability of the background signal, respectively. This paper is accompanied by part 2 of this series, in which these methods are used to process and analyze AMS results on ambient aerosol from two U.K. cities at different times of the year.
2013
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...