Formation and photochemical properties of aqueous brown carbon through glyoxal reactions with glycine

Gao, Yan; Zhang, Yunhong

doi:10.1039/c8ra06913a

Cited by 7 publications

(9 citation statements)

References 43 publications

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“…The φ fl (350 nm) for BrC derived from MG + MA has not been previously reported. In general, the fluorescence quantum yields of MG BrC reported here and by Gao et al are slightly larger than the previous studies of secondary BrC from glyoxal and glycine, as well as SOA samples generated from the oxidation of terpenes with OH and O 3 , which have reported fluorescence quantum yields at 350 nm on the order of ∼0.003–0.01 (0.3–1.0%). , …”

Section: Resultscontrasting

confidence: 76%

“…EEM spectroscopy is now beginning to see further use in the characterization of both laboratory ,− ,− and field − samples of atmospheric aerosols and cloud water. This makes the comparison of environmental water and aerosol measurements increasingly useful for understanding the continuous distribution of CDOM from marine and terrestrial water to aqueous aerosols and cloud water in the atmosphere .…”

Section: Atmospheric Implicationsmentioning

confidence: 99%

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Spectroscopic and Photochemical Properties of Secondary Brown Carbon from Aqueous Reactions of Methylglyoxal

Harrison

Waterson

Bruyn

2020

ACS Earth Space Chem.

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Chromophoric organic compounds in the atmosphere termed brown carbon (BrC) play an important role in tropospheric photochemistry and radiative forcing due to their absorption in the near-UV region of the solar spectrum (300−400 nm). BrC chromophores can form in secondary reactions of carbonyls with ammonium and amine precursors commonly found in aqueous aerosols and cloud water, although there is still uncertainty regarding the contribution of these reactions to atmospheric BrC. Herein, experimental results are presented characterizing the spectroscopic properties of BrC generated from aqueous aerosol/cloud water mimics containing methylglyoxal and ammonium sulfate (MG + AS) or methylamine chloride (MG + MA). Spectroscopic results include mass absorption coefficients, fluorescence quantum yields, and excitation− emission matrix (EEM) spectra, including parallel factor (PARAFAC) analysis. This work also provides a detailed comparison to previous laboratory and field measurements on the classification of aerosols and environmental water with EEM spectroscopy. In addition to spectroscopic characterization, the chemical composition of these samples is investigated using electrospray ionization mass spectrometry and shows the formation of oligomers of methylglyoxal-and nitrogen-containing heterocycles as contributors to absorption in the near-UV consistent with the previous work. The BrC samples were also irradiated using a solar simulator to study the changes in the optical properties and estimate the atmospheric photolytic lifetimes, which have not been previously reported for MG + MA BrC. These results reveal that BrC derived from MG + MA is more stable under solar irradiation than MG + AS BrC with measured atmospheric photolytic half-lives of 39 ± 8 and 12 ± 3 min, respectively.

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Section: Resultscontrasting

confidence: 76%

Section: Atmospheric Implicationsmentioning

confidence: 99%

Spectroscopic and Photochemical Properties of Secondary Brown Carbon from Aqueous Reactions of Methylglyoxal

Harrison

Waterson

Bruyn

2020

ACS Earth Space Chem.

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“…184 Numerous combinations of atmospherically relevant aldehydes and ammonia or amines have been observed to participate in this chemistry, including aldehydes such as methylglyoxal, glyoxal, glycolaldehyde and amines such as glycine and alkylamines. 180,182,[185][186][187][188][189][190][191][192][193][194][195] More recently, pyrazine compounds have also been observed as products from the reaction of methylglyoxal and ammonium (e.g., dimethylpyrazine, Figure 1). 185,196 While these small aldehydes have high volatilities, they are water-soluble and partition to the aqueous phase.…”

Section: Aging Of Imine Brc In the Aqueous Phasementioning

confidence: 99%

“…160,203 Rapid photobleaching by exposure to UV light was observed to occur through loss of compounds across the full molecular weight range, although photolysis was more rapid for lower molecular weight compounds. 159 Lifetimes with respect to UV light exposure were hours for other aldehyde-amine mixtures which form imine BrC, 188,192,193,207 indicating that this class of secondary BrC is not photochemically stable and will not be long lived in the presence of sunlight. Absorption due to this imine BrC may only be significant near to sources or if the source production is large and/or sustained over time.…”

Section: Aging Of Imine Brc In the Aqueous Phasementioning

confidence: 99%

“…These imines and N-heterocycles have also been observed to form through aqueous phase reactions of glyoxal and methylglyoxal, with ammonium or amines (e.g., imidazole-2-carboxaldehyde, Figure ) in both bulk aqueous solutions − and aqueous aerosol . Numerous combinations of atmospherically relevant aldehydes and ammonia or amines have been observed to participate in this chemistry, including aldehydes such as methylglyoxal, glyoxal, glycolaldehyde, and amines such as glycine and alkylamines. ,,− More recently, pyrazine compounds have also been observed as products from the reaction of methylglyoxal and ammonium (e.g., dimethylpyrazine, Figure ). , While these small aldehydes have high volatilities, they are water-soluble and partition to the aqueous phase. Their reactions in the aqueous phase can result in irreversible uptake.…”

Section: Aqueous and In-cloud Reactions Of Brcmentioning

confidence: 99%

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Aging of Atmospheric Brown Carbon Aerosol

Hems

Schnitzler

Liu-Kang

et al. 2021

ACS Earth Space Chem.

129

149

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Emitted by numerous primary sources and formed by secondary sources, atmospheric brown carbon (BrC) aerosol is chemically complex. As BrC aerosol ages in the atmosphere via a variety of chemical and physical processes, its chemical composition and optical properties change significantly, altering its impacts on climate. Research in the past decade has considerably expanded our understanding of BrC reactions in both the gas and condensed phases. We review these recent advances in BrC aging chemistry with a focus on gas phase reactions leading to BrC formation, aqueous and in-cloud processes, and aerosol particle reactions. Connections are made between single component BrC proxies and more complex chemical mixtures, as well as between laboratory and field measurements of BrC chemistry. General conclusions are that chemical change can darken the BrC aerosol particles over short timescales of hours close to source and that considerable photobleaching and oxidative whitening will occur when BrC is a day or more removed from its source.

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Versatile ferrous oxidation–xylenol orange assay for high-throughput screening of lipoxygenase activity

Chrisnasari,

Ewing,

Hilgers

et al. 2024

Appl Microbiol Biotechnol

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Lipoxygenases (LOXs) catalyze dioxygenation of polyunsaturated fatty acids (PUFAs) into fatty acid hydroperoxides (FAHPs), which can be further transformed into a number of value-added compounds. LOXs have garnered interest as biocatalysts for various industrial applications. Therefore, a high-throughput LOX activity assay is essential to evaluate their performance under different conditions. This study aimed to enhance the suitability of the ferrous-oxidized xylenol orange (FOX) assay for screening LOX activity across a wide pH range with different PUFAs. The narrow linear detection range of the standard FOX assay restricts its utility in screening LOX activity. To address this, the concentration of perchloric acid in the xylenol orange reagent was adjusted. The modified assay exhibited a fivefold expansion in the linear detection range for hydroperoxides and accommodated samples with pH values ranging from 3 to 10. The assay could quantify various hydroperoxide species, indicating its applicability in assessing LOX substrate preferences. Due to sensitivity to pH, buffer types, and hydroperoxide species, the assay required calibration using the respective standard compound diluted in the same buffer as the measured sample. The use of correction factors is suggested when financial constraints limit the use of FAHP standard compounds in routine LOX substrate preference analysis. FAHP quantification by the modified FOX assay aligned well with results obtained using the commonly used conjugated diene method, while offering a quicker and broader sample pH range assessment. Thus, the modified FOX assay can be used as a reliable high-throughput screening method for determining LOX activity. Key points • Modifying perchloric acid level in FOX reagent expands its linear detection range • The modified FOX assay is applicable for screening LOX activity in a wide pH range • The modified FOX assay effectively assesses substrate specificity of LOX

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Formation and photochemical properties of aqueous brown carbon through glyoxal reactions with glycine

Abstract: In recent years, brown carbon aerosols, as important contributors to light absorption and climate forcing by aerosols, have been forefront in the field of atmospheric research.

Cited by 7 publications

References 43 publications

Spectroscopic and Photochemical Properties of Secondary Brown Carbon from Aqueous Reactions of Methylglyoxal

Spectroscopic and Photochemical Properties of Secondary Brown Carbon from Aqueous Reactions of Methylglyoxal

Aging of Atmospheric Brown Carbon Aerosol

Versatile ferrous oxidation–xylenol orange assay for high-throughput screening of lipoxygenase activity

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