Structural features of dioxane lignin: A comparative study with milled wood and formaldehyde-stabilized lignins.

Dioxane lignin (DL) is isolated from plant material under mild acidolysis conditions and is widely used in many studies as a representative sample of protolignin, an alternative to milled wood lignin (MWL). However, the structural changes caused by hydrolytic degradation reactions during DL extraction are still poorly understood. In this work, an integrated approach based on 2D NMR and high-resolution mass spectrometry was used to establish the features of the lignin structure on the example of pine lignin isolated using dioxane under various conditions: MWL, DL and "formaldehyde stabilized" lignin (LSF).

1-Butyl-3-methylimidazolium-Based Ionic Liquid in Biomass Fractionation-Green Solvent or Active Reagent Toward Lignin Compounds?

N,N'-Dialkylimidazolium-based ionic liquids are capable of completely dissolving lignocellulosic biomass at elevated temperatures and are considered as promising green solvents for future biorefining technologies. However, the obtained ionic liquid lignin preparations may contain up to several percent nitrogen. This indicates strong interactions between the biopolymer and the IL cation, the nature of which has not yet been clarified.

Polyphenolic Antioxidants in Bilberry Stems and Leaves: A Non-Targeted Analysis by Two-Dimensional NMR Spectroscopy and Liquid Chromatography-High-Resolution Mass Spectrometry.

Compared with those of berries, the stems and leaves of the genus Vaccinium are important and underestimated sources of polyphenols with high antioxidant activity. In the course of this work, aqueous methanol extracts of the aerial parts of common bilberry ( L.) and bog bilberry L.

Determination of Macrolides in Water Using Solid-Phase Extraction and Supercritical Fluid Chromatography-Tandem Mass Spectrometry.

Macrolides are a group of compounds used to treat bacterial infections in humans and animals. Their widespread use results in the contamination of the water environment, which, on the one hand, has a detrimental effect on aquatic organisms and, on the other hand, can lead to the emergence of resistant strains of microorganisms. All of the above determines the need for monitoring of these compounds in the environment, particularly, in water objects.

Analysis of pentacyclic triterpenoids and phytosterols in cloudberry () by LC-MS/MS.

Cloudberry (.) is a plant rich in various biologically active compounds. In this work, the composition and concentrations of pentacyclic triterpenoids (PCTs) and phytosterols in various parts of cloudberries were studied using high-performance liquid chromatography-tandem mass spectrometry by multiple reaction monitoring mode (MRM, targeted analysis) and precursor ion scan mode (non-targeted analysis and semi-quantitative determination).

Comprehensive identification of polyphenolic metabolites in aspen knotwood by combination of 2D NMR and HPLC-HRMS.

Introduction: European aspen (Populus tremula L.) knotwood contains large amounts of polyphenolic metabolites, mainly flavonoids, and can be considered as a promising industrial-scale source of valuable bioactive compounds. Valorization of knotwood extractives requires detailed information on their chemical composition and a relevant analytical methodology.

Analysis of nitrogen-containing rocket fuel transformation products in loamy soil by thermal desorption gas chromatography-tandem mass spectrometry.

Unsymmetrical dimethylhydrazine (UDMH) based rocket fuel, when released into the soil, undergoes oxidative transformations to form a variety of toxic nitrogen-containing products (TPs). Loamy soils containing aluminosilicates (clay) are capable of strong binding and retention of UDMH TPs due to a combination of polar sorption and cation-exchange properties, posing challenges for their extraction and quantification. To overcome this problem, the present study proposes direct thermal desorption (TD) of analytes from loam facilitated by the addition of modifiers competing with UDMH TPs for sorption centers and ensuring their conversion into molecular form.

Polycommunin A, a dihydrocinnamoyl bibenzyl isolated from the moss and its antioxidant activity.

A novel polyphenolic compound named Polycommunin A (1) was discovered in the aerial part of the common haircap moss () widely spread in boreal and temperate climate zones. Aqueous ethanol and extraction of the plant material with further isolation of polyphenolic fraction and preparative HPLC separation allowed obtaining individual compound and identifying it as dimeric dihydrocinnamoyl bibenzyl by NMR spectroscopy and high-resolution tandem mass spectrometry. Polycommunin A demonstrated high antioxidant activity determined by FRAP and PCL assays and comparable to that of Trolox and Quercetin.

Resolution-enhanced Kendrick mass defect analysis for improved mass spectrometry characterization of lignin.

Lignin is a promising renewable source of valuable organic compounds and environmentally benign materials. However, its involvement in economic circulation and the creation of new biorefining technologies require an understanding of its chemical composition and structure. This problem can be overcome by applying mass spectrometry analytical techniques in combination with advanced chemometric methods for mass spectra processing.

Mucolytic Drugs Ambroxol and Bromhexine: Transformation under Aqueous Chlorination Conditions.

Bromhexine and ambroxol are among the mucolytic drugs most widely used to treat acute and chronic respiratory diseases. Entering the municipal wastewater and undergoing transformations during disinfection with active chlorine, these compounds can produce nitrogen- and bromine-containing disinfection by-products (DBPs) that are dangerous for aquatic ecosystems. In the present study, primary and deep degradation products of ambroxol and bromhexine obtained in model aquatic chlorination experiments were studied via the combination of high-performance liquid and gas chromatography with high-resolution mass spectrometry.

Analysis of Softwood Lignans by Comprehensive Two-Dimensional Liquid Chromatography.

Lignans constitute a large group of phenolic plant secondary metabolites possessing high bioactivity. Their accurate determination in plant extracts with a complex chemical composition is challenging and requires advanced separation techniques. In the present study, a new approach to the determination of lignans in coniferous knotwood extracts as the promising industrial-scale source of such compounds based on comprehensive two-dimensional liquid chromatography separation and UV spectrophotometric detection is proposed.

Cocamidopropyl betaine - a potential source of nitrogen-containing disinfection by-products in pool water.

Water treatment for most public pools involves disinfection with active chlorine leading to the formation of disinfection by-products (DBPs). Among them, nitrogen-containing compounds (N-DBPs) having increased toxicity and adverse effects on human health are of the greatest concern. Being the major component of various body washers for swimmers, cocamidopropyl betaine (CAPB) represents a potential and still underestimated anthropogenic precursor of N-DBPs in pool water.

Fractionation of Arctic Brown Algae () Biomass Using 1-Butyl-3-methylimidazolium-Based Ionic Liquids.

Arctic brown algae are considered a promising industrial-scale source of bioactive sub-stances as polysaccharides, polyphenols, and low-molecular secondary metabolites. Conventional technologies for their processing are focused mainly on the isolation of polysaccharides and involve the use of hazardous solvents. In the present study a "green" approach to the fractionation of brown algae biomass based on the dissolution in ionic liquids (ILs) with 1-butil-3-methylimidazolium (bmim) cation with further sequential precipitation of polysaccharides and polyphenols with acetone and water, respectively, is proposed.

Application of 2D NMR Spectroscopy in Combination with Chemometric Tools for Classification of Natural Lignins.

Lignin is considered a promising renewable source of valuable chemical compounds and a feedstock for the production of various materials. Its suitability for certain directions of processing is determined by the chemical structure of its macromolecules. Its formation depends on botanical origin, isolation procedure and other factors.

Comprehensive Characterization of Secondary Metabolites in Fruits and Leaves of Cloudberry ( L.).

Cloudberry ( L.) is a circumpolar boreal plant rich in bioactive compounds and is widely used in food and in folk medicine. In this study, a combination of two-dimensional NMR spectroscopy and liquid chromatography-high-resolution mass spectrometry was used for the comprehensive characterization of secondary metabolites in cloudberry lipophilic and hydrophilic extracts.

Kendrick mass defect analysis - a tool for high-resolution Orbitrap mass spectrometry of native lignin.

Lignin is the second most abundant biopolymer in nature and a promising renewable feedstock for the production of aromatic compounds, composite materials, sorbents, etc. Being a complex mixture of oligomeric molecules with an irregular structure, natural lignin is an extremely difficult object to study. Its molecular level characterization requires advanced analytical techniques among which atmospheric pressure photoionization Orbitrap mass spectrometry holds a promising place.

Determination of Pentacyclic Triterpenoids in Plant Biomass by Porous Graphitic Carbon Liquid Chromatography-Tandem Mass Spectrometry.

Pentacyclic triterpenoids (PCTs), which possess a number of bioactive properties, are considered one of the most important classes of secondary plant metabolites. Their chromatographic determination in plant biomass is complicated by the need to separate a large number of structurally similar compounds belonging to several classes that differ greatly in polarity (monools, diols, and triterpenic acids). This study proposes a rapid, sensitive, and low-cost method for the simultaneous quantification of ten PCTs (3-taraxerol, lupeol, -amyrin, -amyrin, betulin, erythrodiol, uvaol, betulinic, oleanolic, and ursolic acids) by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) using porous graphitic carbon (Hypercarb) as a stationary phase capable of hydrophobic retention and specific interactions with analytes.

Intra-Species Variations of Bioactive Compounds of Two Dictyota Species from the Adriatic Sea: Antioxidant, Antimicrobial, Dermatological, Dietary, and Neuroprotective Potential.

The marine environment has a significant impact on life on Earth. Organisms residing in it are vital for the ecosystem but also serve as an inexhaustible source of biologically active compounds. Herein, the biodiversity of two brown seaweeds, and from the Adriatic Sea, was evaluated.

Solving the mystery of the Chukotka stinky gray whales.

Gray whales (Eschrichtius robustus) constitute an important part of the diet of Chukotka Native population, reaching 30% of consumed food for the inland Chukchas. Over one hundred licenses for whale hunting are issued on an annual basis. After the USSR collapse natives had to hunt whales near the shore from the small boats.

Comprehensive Characterization of Chemical Composition and Antioxidant Activity of Lignan-Rich Coniferous Knotwood Extractives.

A knotwood of coniferous trees containing large amounts of polyphenolic extractives is considered a promising industrial-scale source of lignans possessing antioxidant properties and other bioactivities. The present study is aimed at a detailed characterization of the chemical composition and antioxidant activity of lignan-rich extractives obtained from the knotwood of the Norway spruce, Scotch pine, Siberian fir, and Siberian larch growing in the European North of Russia as a region with a highly developed forest industry. To achieve this, a comprehensive approach based on a combination of two-dimensional NMR spectroscopy with high-performance liquid chromatography-high-resolution Orbitrap mass spectrometry, and the determination of antioxidant activity by the three complementary methods were proposed.

New Oligomeric Dihydrochalcones in the Moss : Identification, Isolation, and Antioxidant Activity.

One of the most widespread representatives of mosses in the temperate and boreal latitudes of the Northern Hemisphere is common haircap (), which is known as the largest moss in the world and widely used in traditional herbal medicine. Polyphenolic compounds constitute one of the most important groups of biologically active secondary metabolites of , however, the available information on their chemical composition is still incomplete and contradictory. In the present study, a group of dihydrochalcone polyphenolic derivatives that were not previously found in mosses was isolated from biomass using pressurized liquid extraction with aqueous acetone.

Data of polycyclic aromatic hydrocarbons concentration in the Siberian Arctic seas sediments.

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.

New Insights into the Thermal Stability of 1-Butyl-3-methylimidazolium-Based Ionic Liquids.

One of the most promising applications of ionic liquids (ILs) with 1-butyl-3-methylimidazolium (bmim) cation is based on their unique ability to dissolve and fractionate lignocellulosic biomass, allowing for the development of green biorefining technologies. A complete dissolution of lignocellulose requires prolonged treatment at elevated temperatures, which can cause the partial degradation of ILs. In the present study, a combination of various analytical techniques (GC-MS, HPLC-HRMS, 2D-NMR, synchronous thermal analysis) was used for the comprehensive characterization of bmim acetate, chloride, and methyl sulfate degradation products formed at 150 °C during 6- and 24-h thermal treatment.

Rapid determination of phthalates in paper products by supercritical fluid chromatography/tandem mass spectrometry.

Phthalic acid esters are widely used as components of industrial and consumer products including paper and cardboard packaging materials in contact with food or human skin. Being endocrine-disrupting chemicals, phthalic acid esters have a negative effect on human health and must be controlled in pulp and paper products. In the present study, supercritical fluid chromatography-tandem mass spectrometry in combination with pressurized liquid extraction was proposed for phthalic acid esters determination in such objects.

Rapid Simultaneous Quantification of 1-Formyl-2,2-Dimethylhydrazine and Dimethylurea Isomers in Environmental Samples by Supercritical Fluid Chromatography-Tandem Mass Spectrometry.

When released to the environment, the rocket fuel unsymmetrical dimethylhydrazine (UDMH) undergoes oxidative transformations, resulting in the formation of an extremely large number of nitrogen-containing transformation products, including isomeric compounds which are difficult to discriminate by common chromatography techniques. In the present work, supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) was proposed for resolving the problem of fast separation and simultaneous quantification of 1-formyl-2,2-dimethylhydrazine (FADMH) as one of the major UDMH transformation products, and its isomers-1,1-dimethylurea (UDMU) and 1,2-dimethylurea (SDMU). 2-Ethylpyridine stationary phase provided baseline separation of analytes in 1.