| Title: | Analysis of organic aerosols using a micro-orifice volatilization impactor coupled to an atmospheric-pressure chemical ionization mass spectrometer |
| Author(s): | Bruggemann M; Vogel AL; Hoffmann T; |
| Journal Title: | Eur J Mass Spectrom (Chichester) |
| ISSN/ISBN: | 1469-0667 (Print) 1469-0667 (Linking) |
| Abstract: | "We present the development and characterization of a combination of a micro-orifice volatilization impactor (MOVI) and an ion trap mass spectrometer (IT/MS) with an atmospheric-pressure chemical ionization (APCI) source. The MOVI is a multi-jet impactor with 100 nozzles, allowing the collection of aerosol particles by inertial impaction on a deposition plate. The pressure drop behind the nozzles is approximately 5%, resulting in a pressure of 96kPa on the collection surface for ambient pressures of 101.3 kPa. The cut-point diameter (diameter of 50% collection efficiency) is at 0.13 microm for a sampling flow rate of 10 L min(-1). After the collection step, aerosol particles are evaporated by heating the impaction surface and transferred into the APCI-IT/MS for detection of the analytes. APCI was used in the negative ion mode to detect predominantly mono- and dicarboxylic acids, which are major oxidation products of biogenic terpenes. The MOVI-APCI-IT/MS instrument was used for the analysis of laboratory-generated secondary organic aerosol (SOA), which was generated by ozonolysis of alpha-pinene in a 100 L continuous-flow reactor under dark and dry conditions. The combination of the MOVI with an APCI-IT/MS improved the detection Limits for small dicarboxylic acids, such as pinic acid, compared to online measurements by APCI-IT/MS. The Limits of detection and quantification for pinic acid were determined by external calibration to 4.4 ng and 13.2 ng, respectively. During a field campaign in the southern Rocky Mountains (USA) in summer 2011 (BEACHON-RoMBAS), the MOVI-APCI-IT/MS was applied for the analysis of ambient organic aerosols and the quantification of individual biogenic SOA marker compounds. Based on a measurement frequency of approximately 5 h, a diurnal cycle for pinic acid in the sampled aerosol particles was found with maximum concentrations at night (median: 10.1 ngm(-3)) and minimum concentrations during the day (median: 8.2 ng m(-3)), which is likely due to the partitioning behavior of pinic acid and the changing phase state of the organic aerosol particles with changing relative humidity" |
| Keywords: | Aerosols/*chemistry Atmospheric Pressure Bicyclic Monoterpenes Carboxylic Acids/*analysis/chemistry Humans Ions/analysis Mass Spectrometry/instrumentation/*methods Monoterpenes/chemistry Oxidation-Reduction Ozone/chemistry Terpenes/analysis/chemistry Vola; |
| Notes: | "MedlineBruggemann, Martin Vogel, Alexander Lucas Hoffmann, Thorsten eng Research Support, Non-U.S. Gov't England 2014/06/03 Eur J Mass Spectrom (Chichester). 2014; 20(1):31-41. doi: 10.1255/ejms.1260" |
