title: Near-infrared laser desorption/ionization aerosol mass spectrometry for investigating primary and secondary organic aerosols under low loading conditions.
abstract: A new method, near-infrared laser desorption/ionization aerosol mass spectrometry (NIR-LDI-AMS), is described for the real time analysis of organic aerosols at atmospherically relevant mass loadings. Use of a single NIR laser pulse to vaporize and ionize particle components deposited on an aluminum probe results in minimal fragmentation to produce exclusively intact pseudomolecular anions at [M-H](-). Limits of detection (total particulate mass sampled) for oxidized compounds of relevance to atmospheric primary and secondary organic aerosol range from 89 fg for pinic acid to 8.8 pg for cholesterol. NIR-LDI-AMS was used in conjunction with the University of Vermont Environmental Chamber to study secondary organic aerosol (SOA) formation from ozonolysis of limonene at total aerosol mass loadings ranging from 3.2 to 25.0 μg m(-3) and with a time resolution of several minutes. NIR-LDI-AMS permitted direct delineation between gas-phase, homogeneous SOA formation and subsequent heterogeneous aerosol processing by ozone.
authors.affiliation: Department of Chemistry, University of Vermont, Burlington, Vermont 05452, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Geddes
authors.forename: Brian
authors.initials: B
authors.lastname: Nichols
authors.forename: Stevenson
authors.initials: S
authors.lastname: Flemer
authors.forename: Jessica
authors.initials: J
authors.lastname: Eisenhauer
authors.forename: James
authors.initials: J
authors.lastname: Zahardis
authors.forename: Giuseppe A
authors.initials: GA
authors.lastname: Petrucci
mesh_terms: D000336:Aerosols / Q000737:chemistry*; D000393:Air Pollutants / Q000737:chemistry*; D000535:Aluminum / Q000737:chemistry; D002784:Cholesterol / Q000737:chemistry; D053138:Cyclohexenes / Q000737:chemistry; D007834:Lasers; D000077222:Limonene; D009930:Organic Chemicals / Q000737:chemistry*; D010126:Ozone / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013729:Terpenes / Q000737:chemistry
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D053138:Cyclohexenes; D009930:Organic Chemicals; D013729:Terpenes; D010126:Ozone; D002784:Cholesterol; D000077222:Limonene; D000535:Aluminum