title: Application of Direct Analysis in Real Time-Mass Spectrometry (DART-MS) to the study of gas-surface heterogeneous reactions: focus on ozone and PAHs.
abstract: A novel analytical method is presented whereby Direct Analysis in Real Time-Mass Spectrometry (DART-MS) is applied to the study of gas-surface heterogeneous reactions. To illustrate the capabilities of the approach, the kinetics of a well-studied reaction of surface-bound polycyclic aromatic hydrocarbons with ozone are presented. Specifically, using helium as the reagent gas and with the DART heater temperature of 500 °C, nanogram quantities of benzo[e]pyrene (BeP) deposited on the outside of glass melting point capillary tubes were analyzed in positive ion mode with a limit of detection of 40 pg. Using bis(2-ethylhexyl) sebacate as an internal standard, the kinetics of the ozone-BeP reaction were assessed by determining the surface-bound BeP decays, after oxidation in an off-line reaction cell. The reaction is demonstrated to follow the Langmuir-Hinshelwood mechanism, known to prevail for heterogeneous reactions of this type. In addition, a wide array of oxygenated, condensed-phase products has been observed. The present work demonstrates the capability of the DART-MS technique to investigate the heterogeneous chemistry taking place on a wide range of surfaces, such as those that form in both outdoor and indoor environments.
authors.affiliation: Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Shouming
authors.initials: S
authors.lastname: Zhou
authors.affiliation: Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Forbes
authors.affiliation: Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Jonathan P D
authors.initials: JP
authors.lastname: Abbatt
mesh_terms: D005740:Gases / Q000032:analysis; D007700:Kinetics; D013058:Mass Spectrometry / Q000295:instrumentation; D010126:Ozone / Q000032:analysis*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors
chemical_list: D005740:Gases; D011084:Polycyclic Aromatic Hydrocarbons; D010126:Ozone