GC- and UHPLC-MS Profiles as a Tool to Valorize the Red Alga Asparagopsis armata

Asparagopsis armata Harvey is a red alga native from the southern hemisphere and then introduced in the Mediterranean Sea and the Atlantic Ocean, including the Azores Archipelago, where it is considered an invasive alga. Some studies show that the extracts exhibit antimicrobial and antifouling activities, and it is incorporated in some commercialized cosmetic products. (e.g., Ysaline®). However, knowledge of this species chemical composition is scarce. The GC-MS and UHPLC-MS profiles of both the nonpolar and polar extracts were established to contribute to this problem solution. According to the results, A. armata is rich in a great structural variety of halogenated lipophilic and aromatic compounds, some of them identified here for the first time. In the lipophilic extract, 25 compounds are identified, being the halogenated compounds and fatty acids, the two major compound families, corresponding to 54.8% and 35.7% of identified compounds (224 and 147 mg/100 g of dry algae, respectively). The 1,4-dibromobuten-1-ol and the palmitic acid are the two most abundant identified compounds (155 and 83.4 mg/100 g of dry algae, respectively). The polar extract demonstrated the richness of this species in brominated phenolics, from which the cinnamic acid derivatives are predominant. The results obtained herein open new perspectives for valuing the A. armata as a source of halogenated compounds and fatty acids, consequently improving its biotechnological and economic potential. Promoting this seaweed and the consequent increase in its demand will contribute to biodiversity conservation and ecosystem sustainability.

A Review: Halogenated Compounds from Marine Actinomycetes

Marine actinomycetes, Streptomyces species, produce a variety of halogenated compounds with diverse structures and a range of biological activities owing to their unique metabolic pathways. These halogenated compounds could be classified as polyketides, alkaloids (nitrogen-containing compounds) and terpenoids. Halogenated compounds from marine actinomycetes possess important biological properties such as antibacterial and anticancer activities. This review reports the sources, chemical structures and biological activities of 127 new halogenated compounds originated mainly from Streptomyces reported from 1992 to 2020.

Steric vs Electronic Effects: A New Look into Stability of Diastereomers, Conformers and Constitutional Isomers

A quantum chemical investigation of the stability of compounds with identical formulas was carried out on 23 classes of halogenated compounds made of H, F, Cl, Br, I, C, N, P, O and S atoms. All possible structures were generated by combinatorial approach and studied by statistical methods. The prevalence of formula in which its <i>Z</i> configuration, <i>gauche</i> conformation and meta isomer are the most stable forms is calculated and discussed. Quantitative and qualitative models to explain the stability of the 23 classes of halogenated compounds were also proposed.<br>

The Influence of Copper on Halogenation/Dehalogenation Reactions of Aromatic Compounds and Its Role in the Destruction of Polyhalogenated Aromatic Contaminants

The effect of copper and its compounds on halogenation and dehalogenation of aromatic compounds will be discussed in the proposed article. Cu oxidized to appropriate halides is an effective halogenation catalyst not only for the synthesis of halogenated benzenes or their derivatives as desired organic fine chemicals, but is also an effective catalyst for the undesirable formation of thermodynamically stable and very toxic polychlorinated and polybrominated aromatic compounds such as polychlorinated biphenyls, dibenzo-p-dioxins and dibenzofurans accompanied incineration of waste contaminated with halogenated compounds or even inorganic halides. With appropriate change in reaction conditions, copper and its alloys or oxides are also able to effectively catalyze dehalogenation reactions, as will be presented in this review.

Detecting and assessing trends of CFCs and substitutes from IASI measurements

&lt;p&gt;The first Infrared Atmospheric Sounding Instrument (IASI) on the Metop satellites suite has achieved more than 13 years of continuous operation. The instrument stability and the consistency between the different instruments on the successive Metop (A, B and C) is remarkable and offer the potential to investigate trends in the concentration of various species better than with any other previous or current hyperspectral IR sounder. The low noise of IASI radiances is also such that even weakly absorbing species can be identified, on single or at least on averaged spectra. In this work we exploit the first decadal record of IASI measurements to (1) detect and monitor halogenated compounds regulated by the Montreal protocol (CFCs) or used as substitutes (HCFCs, HFCs), as well as fluorinated compounds (CF&lt;sub&gt;4&lt;/sub&gt;, SF&lt;sub&gt;6&lt;/sub&gt;) and potentially short lived chlorine species, for which substantial emissions are suspected (2) give a first assessment of the trend evolution of these species over the 2008-2017 period covered by IASI on Metop-A. This is done by targeting various geographical areas on the globe and examining the remote oceanic and continental source regions separately. The trend evolution in the different chemical species, either negative or positive, is validated against what is observed from ground-based measurement networks. We will conclude by assessing the usefulness of IASI and follow-on mission to contribute to global measurements of ozone depleting substances.&lt;/p&gt;

Review and Survey of Methods for Analysis of Impurities in Hydrogen for Fuel Cell Vehicles According to ISO 14687:2019

Gaseous hydrogen for fuel cell electric vehicles must meet quality standards such as ISO 14687:2019 which contains maximal control thresholds for several impurities which could damage the fuel cells or the infrastructure. A review of analytical techniques for impurities analysis has already been carried out by Murugan et al. in 2014. Similarly, this document intends to review the sampling of hydrogen and the available analytical methods, together with a survey of laboratories performing the analysis of hydrogen about the techniques being used. Most impurities are addressed, however some of them are challenging, especially the halogenated compounds since only some halogenated compounds are covered, not all of them. The analysis of impurities following ISO 14687:2019 remains expensive and complex, enhancing the need for further research in this area. Novel and promising analyzers have been developed which need to be validated according to ISO 21087:2019 requirements.