Publications by authors named "Sergey Pokryshkin"

The Northern Dvina River is one of the main sources of microplastic pollution entering to the White and Barents Seas. The coastal and bottom sediments of this river play an important role as a transfer link of microplastics. With Py-GC/MS and μFT-IR methods, it was found that the sediments contain up to 350 mg/kg or 650 particles/kg of microplastic (dry weight).

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Article Synopsis
  • The study focuses on how the ratio of monomeric units in lignin influences its processing strategies and methods for analysis.
  • Different thermal decomposition techniques, such as TD-GC/MS and Py-GC/MS, were explored, with findings indicating that product composition varies based on the method used, affecting the quantification of lignin structural fragments.
  • Optimal conditions for measuring lignin were determined, highlighting the effectiveness of DS-Py-GC/MS with specific sample weights and heating rates, while HSQC NMR served as a validation technique for assessing lignin content.
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Polycyclic Aromatic Hydrocarbons (PAHs) are one of the most dangerous persistent organic pollutants in the Arctic. They have different sources and pathways of entering in to the environment. Because of their lipophilic properties, PAHs can easily accumulate in marine sediments.

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Polycyclic Aromatic Hydrocarbons (PAHs) are among the main persistent organic pollutants in the Arcticwhich enter the polar region from lower latitudes by air transport and ocean currents and accumulate in marine sediments. This work represents the first study in 25 years of the least studied and hard-to-reach areas of Siberian arctic seas. Sixteen priority PAHs as well as 1- and 2-methylnaphthalenes were analyzed by gas chromatography - tandem mass spectrometry in the twenty-four sediment samples taken from Kara, Laptev and East Siberian Seas in October 2020.

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Understanding the chemical structure of lignin in the plant phloem contributes to the systematics of lignins of various biological origins, as well as the development of plant biomass valorization. In this study, the structure of the lignin from birch phloem has been characterized using the combination of three analytical techniques, including 2D NMR, Py-GC/MS, and APPI-Orbitrap-HRMS. Due to the specifics of the phloem chemical composition, two lignin preparations were analyzed: a sample obtained as dioxane lignin (DL) by the Pepper's method and DL obtained after preliminary alkaline hydrolysis of the phloem.

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Studies of the chemical composition of atmospheric aerosols, rain water and snow in various regions of the globe quite often show the presence of pyridine and a number of its low mass derivatives. Nevertheless, the sources of those compounds in the environment have not yet been established and definitely require elucidation, supported by reliable experimental results. In the present work the chemical composition of peat combustion products as one of the important sources of atmospheric aerosol emission is studied by two-dimensional gas chromatography - high-resolution mass spectrometry with a focus on the detection of pyridine derivatives.

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Article Synopsis
  • The paper analyzes the chemical structure of Araucaria lignin, a unique relic plant from the Permian period, using various advanced analytical techniques.
  • It identifies distinct structural features of Araucaria lignin that set it apart from modern coniferous lignins and reveals its unique paramagnetic properties.
  • For the first time, the research classifies Araucaria lignin as compositionally heterogeneous GH lignins, a classification not seen in contemporary lignins.
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As a renewable source of unique aromatic compounds, lignin attracts the attention of many researchers. However, for its successful application, it is necessary to have a clear and accurate idea of its chemical structure. Therefore, it is necessary to expand knowledge about the structure of lignins of various nature using the informative analytical methods.

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The increased use of sunscreens and other cosmetics containing UV filters causes human and environmental burden. Avobenzone is a widely used UV filter. In its pure form it is known to undergo several transformations including photo-isomerisation, photodegradation, and halogenation.

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