Mechanistic Insights on the Photosensitized Chemistry of a Fatty Acid at the Air/Water Interface.
Interfaces are ubiquitous in the environment and many atmospheric key processes, such as gas deposition, aerosol, and cloud formation are, at one stage or another, strongly impacted by physical and chemical processes occurring at interfaces. Here, the photoinduced chemistry of an air/water interface coated with nonanoic acid-a fatty acid surfactant we use as a proxy for chemically complex natural aqueous surface microlayers-was investigated as a source of volatile and semivolatile reactive organic species. The carboxylic acid coating significantly increased the propensity of photosensitizers, chosen to mimic those observed in real environmental waters, to partition to the interface and enhance reactivity there. Photochemical formation of functionalized and unsaturated compounds was systematically observed upon irradiation of these coated surfaces. The role of a coated interface appears to be critical in providing a concentrated medium allowing radical-radical reactions to occur in parallel with molecular oxygen additions. Mechanistic insights are provided from extensive analysis of products observed in both gas and aqueous phases by online switchable reagent ion-time of flight-mass spectrometry and by off-line ultraperformance liquid chromatography coupled to a Q Exactive high resolution mass spectrometer through heated electrospray ionization, respectively.
Univ Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON, Institut de recherches sur la catalyse et l'environnement de Lyon, 2 avenue Albert Einstein, Villeurbanne, France.
Liselotte
L
Tinel
Univ Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON, Institut de recherches sur la catalyse et l'environnement de Lyon, 2 avenue Albert Einstein, Villeurbanne, France.
Stéphanie
S
Rossignol
Université Clermont Auvergne, Université Blaise Pascal , Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand, France.
Angelica
A
Bianco
Univ Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON, Institut de recherches sur la catalyse et l'environnement de Lyon, 2 avenue Albert Einstein, Villeurbanne, France.
Monica
M
Passananti
Univ Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON, Institut de recherches sur la catalyse et l'environnement de Lyon, 2 avenue Albert Einstein, Villeurbanne, France.
Sébastien
S
Perrier
State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640, China.
Xinming
X
Wang
Université Clermont Auvergne, Université Blaise Pascal , Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand, France.
Marcello
M
Brigante
Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
D James
DJ
Donaldson
Univ Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON, Institut de recherches sur la catalyse et l'environnement de Lyon, 2 avenue Albert Einstein, Villeurbanne, France.
Christian
C
George
D000336:Aerosols; D055598:Chemical Phenomena; D005227:Fatty Acids; D055668:Photochemical Processes; D014867:Water / Q000737:chemistry*
D000336:Aerosols; D005227:Fatty Acids; D014867:Water