Molecular investigation of the multi-phase photochemistry of Fe(iii)–citrate in aqueous solution

Abstract

Iron (Fe) is ubiquitous in nature and found as FeII or FeIII in minerals or as dissolved ions Fe2+ or Fe3+ in aqueous systems. The interactions of soluble Fe have...

Molecular and Structural Characterization of Isomeric Compounds in Atmospheric Organic Aerosol Using Ion Mobility-Mass Spectrometry

“…Formation of organosulfate compounds in PSOA from the evaporative drying in the presence of sulfuric acid is expected to also increase the CCS. Additionally, the discrimination between the ring-retained, ring-opening, and isomeric products of toluene-derived SOA under OH oxidation and high/low NO x is also important to distinguish in complex SOA mixtures. , Structural characterization of water-soluble metal-organic complexes , involving small carboxylic acids with iron (Fe 3+ ) from SOA, environmental samples, and cloud water can also be performed using IM-MS for untargeted analyses. More IM studies are needed to expand accurate CCS measurements to a broad range of atmospheric molecules relevant to SOA formation and aging.…”

Emerging investigator series: aqueous photooxidation of live bacteria with hydroxyl radicals under cloud-like conditions: insights into the production and transformation of biological and organic matter originating from bioaerosols

“…Several methods have been used by the atmospheric community to graphically visualize and classify peaks in complex MS datasets based on the molecular formulae and elemental ratios of the peaks, including the Van Krevelen (VK) diagram (H/C vs. O/C), 69 carbon oxidation state vs. number of C atoms diagram, 70 and DBE vs. number of C atoms diagram. 71 To better understand how the composition of biological and organic compounds released from the four bacterial strains evolved during photooxidation, the O/C and H/C ratios of the identied WS and WIS compounds were visualized on VK diagrams, which is a commonly used tool to graphically visualize and classify compounds in cloud water. 50,72 The WS and WIS compounds were categorized into seven groups based on the region of the VK diagrams that they were in according to their combined O/C and H/C ratios.…”

Common Photo-oxidative Decarboxylation Mechanism in Iron Hydroxy Carboxylate Complexes

“…1,2 Photochemical fluxes of CO 2 can be a significant portion of total emissions from some environments, 3,4 but light-driven mineralization pathways remain poorly understood. 5 The sensitivity of DOM to photooxidation depends on many environmental conditions, such as pH and the presence of metal ions. 6−9 In particular, iron (Fe) forms complexes with DOM carboxylate moieties, 10,11 which can enhance DOM photoreactivity.…”

“…Photochemical oxidation of dissolved organic matter (DOM) in surface waters and atmospheric aerosols is a major pathway for the conversion of organic molecules or moieties to carbon dioxide (CO 2 ). , Photochemical fluxes of CO 2 can be a significant portion of total emissions from some environments, , but light-driven mineralization pathways remain poorly understood . The sensitivity of DOM to photo-oxidation depends on many environmental conditions, such as pH and the presence of metal ions. − In particular, iron (Fe) forms complexes with DOM carboxylate moieties, , which can enhance DOM photoreactivity. , Many Fe­(III)-organic compounds strongly absorb light in the UV–visible range, and photoexcitation can cause ligand-to-metal charge transfer that reduces Fe­(III) to Fe­(II) and oxidizes the organic ligand. , Photolysis of Fe-carboxylate complexes can lead to decarboxylation, in which the COOH group is released as CO 2 .…”