Particulate Organic Matter Detection Using a Micro-Orifice Volatilization Impactor Coupled to a Chemical Ionization Mass Spectrometer (MOVI-CIMS)

作者：Yatavelli Reddy L N; Thornton Joel A^*

来源：Aerosol Science and Technology, 2010, 44(1): 61-74.

DOI：10.1080/02786820903380233

We describe a new method, Micro-Orifice Volatilization Impactor-CIMS (MOVI-CIMS) that couples two well-proven techniques, inertial impaction and chemical ionization mass spectrometry (CIMS). This technique allows both gas and condensed-phase composition data to be obtained on a semi-continuous basis. Gas-phase compounds are analyzed while particles are collected on a post. This collection step is followed by thermal desorption in an inert atmosphere to detect condensed-phase compounds. Differentiation between gas and condensed-phase compounds can likely occur on hourly or shorter timescales. The unique aspects of this approach are the use of an impactor with 100 nozzles that allows particle collection at a pressure within 15% of ambient and the ability to use a wide suite of negative and positive reagent ions. A sample flow rate of 10 L min(-1) results in a cut-point diameter (d(50), diameter of 50% collection efficiency) of 0.13 mu m. We demonstrate the capabilities of this technique by applying it to the determination of mono-and dicarboxylic acid vapor pressures and studies of the heterogeneous oxidation of oleic acid aerosol particles.

• 出版日期2010