title: Surface Enhanced Raman Spectroscopy Enables Observations of Previously Undetectable Secondary Organic Aerosol Components at the Individual Particle Level.
abstract: The first use of surface enhanced Raman spectroscopy (SERS) to detect trace organic and/or inorganic species in ambient atmospheric aerosol particles is presented. This new analytical method provides direct, spectroscopic detection of species present at attogram to femtogram levels in individual submicrometer atmospheric particles. An array of spectral features resulting from organic functional groups in secondary organic aerosol (SOA) material were observed in individual particles impacted on silver nanoparticle-coated substrates. The results demonstrate the complexity of organic and inorganic species in SOA formed by oxidation of biogenic volatile organic compounds (BVOCs) at the single particle level. While SOA composition is frequently assumed to be homogeneous between and within individual particles, substantial particle-to-particle variability in SOA composition and changes on scales <1 μm were observed. The observations obtained with this new method demonstrate the power of SERS to probe difficult to detect inter- and intraparticle variability in ambient SOA particles.
authors.affiliation: †Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Craig
authors.affiliation: †Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States.
authors.forename: Amy L
authors.initials: AL
authors.lastname: Bondy
authors.affiliation: †Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States.|‡Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan 48109, United States.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Ault
mesh_terms: D000336:Aerosols / Q000737:chemistry*; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D053768:Metal Nanoparticles / Q000737:chemistry; D010316:Particle Size; D012834:Silver / Q000737:chemistry; D013059:Spectrum Analysis, Raman; D055549:Volatile Organic Compounds / Q000032:analysis* / Q000737:chemistry
chemical_list: D000336:Aerosols; D055549:Volatile Organic Compounds; D012834:Silver