Fluorophores in surface freshwaters: importance, likely structures, and possible impacts of climate change

Vione, Davide; Minero, Claudio; Carena, Luca

doi:10.1039/d1em00273b

Cited by 9 publications

(5 citation statements)

References 112 publications

(117 reference statements)

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“…Over the past two decades, numerous studies have suggested that humic-like and protein-like fluorescence can serve as proxies for lignin and amino acid concentrations in DOM. , The protein-like fluorescence in DOM is primarily derived from aromatic amino acids, such as Tyr and Trp, in aquatic environments. Our results demonstrated that the reaction of Trp and Tyr with 3 C* generates LLPO, which can directly oxidize R-PhOH and CDOM-related reductants.…”

Section: Discussionmentioning

confidence: 99%

Effects of Tryptophan and Tyrosine on the Transformation of Monophenols in Chromophoric Dissolved Organic Matter Solutions: Enhance the Forward Transformation and Reduce the Reverse Transformation

Zhou,

Zhang

2024

Environ. Sci. Technol.

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Tryptophan (Trp) and tyrosine (Tyr) are the primary precursors of protein-like components in dissolved organic matter. Phenolic compounds are ubiquitous in aquatic environments and are considered the main electron donor in chromophoric dissolved organic matter (CDOM). Our results showed that Trp and Tyr (50 μM) enhanced the transformation of six monophenols (20 μM) with varying numbers of −CH 3 and −OCH 3 substituent groups by a factor of 1.0−1.8. The enhancement factor increased with the ratio of Trp (Tyr) to monophenols. In four different CDOM solutions (5 mg C/L, pH 8.0), a maximum enhancement factor of 3.2− 6.7 was observed at a Trp/monophenol concentration ratio of 50. Conversely, monophenols greatly inhibited the transformation of Trp or Tyr. The enhancement factor decreased as the initial pH increased from 3.0 to 10.0. Additionally, the enhancement factor was not directly proportional to the oxidation potential of monophenol. We propose that the promotion effects are generated through the direct oxidation of monophenols by Trp (Tyr) radicals as well as through the reaction between Trp (Tyr) radicals and the one-electron reductant of CDOM.

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Section: Discussionmentioning

confidence: 99%

Effects of Tryptophan and Tyrosine on the Transformation of Monophenols in Chromophoric Dissolved Organic Matter Solutions: Enhance the Forward Transformation and Reduce the Reverse Transformation

Zhou,

Zhang

2024

Environ. Sci. Technol.

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“…From a mechanistic point of view, this photochemical process could involve dimerisation/oligomerisation, as well as hydroxylation of the precursor molecules (see Scheme S1 in the Supplementary Material, hereinafter SM, for a possible example of such processes) (De Laurentiis et al, 2013;Hoffer et al, 2004;Mabato et al, 2022). Indeed, evidence suggests that phenolic oligomers and polyhydroxylated aromatic compounds are reasonable humic fluorophores (Vione et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

“…Excitation-emission matrix (EEM) fluorescence spectroscopy is one of the most straightforward ways to characterise organic matter in natural water samples (Minor et al, 2014;Stedmon et al, 2003). The signals that are most often detected in EEM spectra are those of proteins and HS (Vione et al, 2021). Protein fluorescence is detected based on the main fluorophores, i.e.…”

Section: Introductionmentioning

confidence: 99%

Photoinduced production of substances with humic-like fluorescence, upon irradiation of water samples from alpine lakes

et al. 2023

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“…Fluorescence excitation emission matrix (EEM) spectroscopy has found many applications in the analysis of, for example, food samples, − machinery fluids, , environmental samples , such as water − and soil, , and even neutrino scintillator liquids . EEM spectroscopy is usually performed by scanning a light sourceusually a broadband lamp coupled to a monochromatorand collecting the fluorescence using either an array detector or a second monochromator and broadband detector.…”

Section: Introductionmentioning

confidence: 99%

Rapid Fluorescence EEM Spectroscopy Using Super-Cycle Hadamard-Transform Multiplexing

Ferguson,

Loock

2023

Anal. Chem.

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Hadamard-transform (HT) multiplexing has recently been applied to increasingly complex spectroscopic techniques. It had been shown that the data acquisition time for fluorescence excitation emission matrix (EEM) spectroscopy can be reduced by 1 or 2 orders of magnitude using HT multiplexing of the excitation light using a programmable light source. In these previous studies, the data acquisition rate had been limited by the time it took to record an EEM, that is, to complete one cycle of multiplexed excitation spectra. The extraction of chemical information, such as concentration and chemical identity, is then obtained from parallel factor (PARAFAC) analysis of the sequence of EEMs. In this contribution, we increase the data acquisition rate by another order of magnitude, limited ultimately by the time it takes to record a single excitation spectrum. Our algorithm is entirely based on improved data processing, that is, it can be applied to previously recorded HT multiplexed data sets. The algorithm is based on three previously unexplored approaches: (1) we perform a PARAFAC multivariate analysis on the raw (multiplexed) data set, (2) the time-independent PARAFAC loading vectors are obtained prior to obtaining the timedependent score vectors, and (3) when loading vectors are difficult to obtain from the EEMs, we instead use a rolling-average approach to considerably increase the stability of the fit. Analysis of experimental data shows that the scores of fluorescence EEMs with seven excitation wavelengths and over 1000 emission wavelengths can be obtained in less than 20 ms.

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Fluorophores in surface freshwaters: importance, likely structures, and possible impacts of climate change

Abstract: Fluorescence spectroscopy is one of the most useful techniques that are currently available for the characterisation of organic matter in natural water samples, because it combines easy availability of instrumentation,...

Cited by 9 publications

References 112 publications

Effects of Tryptophan and Tyrosine on the Transformation of Monophenols in Chromophoric Dissolved Organic Matter Solutions: Enhance the Forward Transformation and Reduce the Reverse Transformation

Effects of Tryptophan and Tyrosine on the Transformation of Monophenols in Chromophoric Dissolved Organic Matter Solutions: Enhance the Forward Transformation and Reduce the Reverse Transformation

Photoinduced production of substances with humic-like fluorescence, upon irradiation of water samples from alpine lakes

Rapid Fluorescence EEM Spectroscopy Using Super-Cycle Hadamard-Transform Multiplexing

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