Cerrato, A., Cannazza, G., Capriotti, A.L., Citti, C., La Barbera, G., Laganà, A., Montone, C.M., Piovesana, S., Cavaliere, C., 2020. A new software-assisted analytical workflow based on high-resolution mass spectrometry for the systematic study of phenolic compounds in complex matrices. Talanta 209, 120573.

http://www.sciencedirect.com/science/article/pii/S0039914019312068 Polyphenols are a broad class of plant secondary metabolites which carry out several biological functions for plant growth and protection and are of great interest as nutraceuticals for their antioxidant properties. However, due to their structural variability and complexity, the mass-spectrometric analysis of polyphenol content in plant matrices is still an issue. In this work, a novel approach for the identification of several classes of polyphenol derivatives based on ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry was developed. First, mass-spectrometric parameters were optimized in order to obtain a large set of diagnostic product ions for their high-confidence identification. The software Compound Discoverer 3.0 was then implemented with a comprehensive database of 45,567 polyphenol derivatives and with mass- spectrometric data for their building blocks, resulting in a specific tool for the semi-automatic identification of flavonoids, anthocyanins, ellagitannins, proanthocyanidins and phenolic acids. The method was then applied to the identification of polyphenols in industrial hemp (Cannabis sativa), a matrix whose use is recently spreading for pharmaceutical and nutraceutical purposes, resulting in the identification of 147 compounds belonging to the classes of flavonoids, proanthocyanidins and phenolic acids. The proposed method is applicable to the polyphenol profiling of any plant matrix and it is not dependent on data in the literature for their identification, allowing the discovery of compounds which have been never identified before.

Chan, E.W., Shiller, A.M., Joung, D.J., Arrington, E.C., Valentine, D.L., Redmond, M.C., Breier, J.A., Socolofsky, S.A., Kessler, J.D., 2020. Investigations of aerobic methane oxidation in two marine seep environments: Part 2 - Isotopic kinetics. Journal of Geophysical Research: Oceans 124, 8392-8399.

https://doi.org/10.1029/2019JC015603 Abstract: During aerobic oxidation of methane (CH ) in seawater, a process which mitigates atmospheric 4 12 13 emissions, the C-isotopologue reacts with a slightly greater rate constant than the C-isotopologue, leaving the residual CH isotopically fractionated. Prior studies have attempted to exploit this systematic isotopic 4 fractionation from methane oxidation to quantify the extent that a CH pool has been oxidized in seawater. 4 However, cultivation-based studies have suggested that isotopic fractionation fun damentally changes as a microbial population blooms in response to an influx of reactive substrates. Using a systematic mesocosm incubation study with recently collected seawater, here we investigate the fundamental isotopic kinetics of aerobic CH oxidation during a microbial bloom. As detailed in a companion paper, seawater samples were 4 collected from seep fields in Hudson Canyon, U.S. Atlantic Margin, and atop Woolsey Mound (also known as Sleeping Dragon) which is part of lease block MC118 in the northern Gulf of Mexico, and used in these investigations. The results from both Hudson Canyon and MC118 show that in these natural environments isotopic fraction for CH oxidation follows a first-order kinetic process. The results also show that the isotopic 4 fractionation factor remains constant during this methanotrophic bloom once rapid CH oxidation begins and 4 that the magnitude of the fractionation factor appears correlated with the first-order reaction rate constant. These findings greatly simplify the use of natural stable isotope changes in CH to assess the extent that CH is 4 4 oxidized in seawater following seafloor release. Plain Language Summary: The aerobic oxidation of methane in seawater is a process that prevents methane produced in the oceanic environment from being emitted to the atmosphere. During this process, isotopic forms of methane are oxidized at slightly different rates leading to changes in the natural methane isotope ratios with the extent of oxidation. While these changes in isotope ratios would seem to be a proxy for the extent of methane oxidation, laboratory-based studies involving pure cultures have shown that these isotope ratio changes vary as a microbial population blooms in response to an increase in substrates. This study systematically measured the stable isotope changes that are associated with aerobic methane oxidation in recently collected seawater collected from regions of active seafloor methane release along the U.S. Atlantic margin and the Gulf of Mexico. Results show that these isotope changes are systematic during methane oxidation, greatly simplifying the use of isotope changes to determine the extent of methane oxidation.