title: Identification of weak and strong organic acids in atmospheric aerosols by capillary electrophoresis/mass spectrometry and ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry.
abstract: A novel approach using a combination of capillary electrophoresis/mass spectrometry (CE/MS) and off-line Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) revealed the structural details of acidic constituents of atmospheric organic aerosol. Both techniques utilized electrospray ionization (ESI), a soft ionization method, to facilitate the analysis of complex mixtures of organic compounds. CE/ESI-MS using an UltraTrol LN-precoated capillary and acidic background electrolytes at different pH values (2.5 and 4.7) was used to differentiate between weak (carboxylic) and strong (sulfonic) organic acids. On the basis of the electrophoretic mobility, m/z constraints from CE/ESI(-)-MS, and elemental composition information retrieved from off-line FTICR-MS, a variety of aliphatic and aromatic carboxylic acids (CHO-bearing molecules), nitrogen-containing carboxylic acids (CHON-bearing molecules), organosulfates (CHOS-bearing molecules), and (nitrooxy)organosulfates (CHONS-bearing molecules) were tentatively identified in the Oasis-HLB-extracted urban PM(2.5) (particulate matter with an aerodynamic diameter of <2.5 μm). The chemical known/unknown structures of detected compounds were confirmed by the semiempirical Offord model (effective mobility linearly correlated to Z/M(2/3)). The majorities of the identified compounds are products of atmospheric reactions and are known contributors to secondary organic aerosols.
authors: Analysis and Air Quality Section, Air Quality Research Division, Atmospheric Science and Technology Directorate, Science and Technology Branch, Environment Canada, Ottawa, Ontario, Canada K1A 0H3.
authors: Mahmoud M
authors: MM
authors: Yassine
authors: Ewa
authors: E
authors: Dabek-Zlotorzynska
authors: Mourad
authors: M
authors: Harir
authors: Philippe
authors: P
authors: Schmitt-Kopplin
mesh_terms: D000336:Aerosols / Q000737:chemistry*; D001274:Atmospheric Pressure; D002264:Carboxylic Acids / Q000032:analysis*; D019075:Electrophoresis, Capillary; D005583:Fourier Analysis; D013058:Mass Spectrometry; D052638:Particulate Matter / Q000737:chemistry; D013451:Sulfonic Acids / Q000032:analysis*
chemical_list: D000336:Aerosols; D002264:Carboxylic Acids; D052638:Particulate Matter; D013451:Sulfonic Acids