Latvian Darkhead (LD) is a local sheep breed and a genetic resource in Latvia. Preservation and development of the sheep population in the local region is important for the recultivation of fields, it serves as a source for export and local use, as well as waste wool can be applied for developing new products, for example, sorbents for volatile organic pollutants. Therefore, investigation of the sorption properties of the LD sheep wool fibers is under interest. In addition, modification options of the wool for improvement of properties are viewed. Therefore, in the present work, sheep wool fibers as well as accelerated electron-irradiated fibers are analyzed and compared. Fourier transform infrared (FTIR) spectrometry is applied to develop the sorption testing system of volatile organic compounds. An analytical system consisting of a volatile organic compound source, sheep wool filter, and FTIR spectrometry cell is tested and applied for analysis of wool sorption properties for acetone molecules. Registration of the FTIR spectra was performed within the range of 600-4000 cm-1, in the nitrogen flow of about 150mL/min. FTIR analysis shows, that the accelerated electron irradiated sheep wool fibers absorb acetone of about 33% more than non-irradiated fibers. The obtained results will be used for developing recommendations for filter producers to fabricate filter components containing LD sheep wool fibers.

A new method for quantitative analysis of several biomarkers and pharmaceutical compounds in wastewater has been developed employing nanoflow liquid chromatography with Orbitrap mass spectrometry. An easy dilute‐and‐shoot approach has been used for sample preparation with a dilution factor of 5. Improved retention of ionic and highly polar compounds has been achieved by the addition of tetrabutylammonium bromide as an ion pair reagent into the final diluted sample. The new nanoflow liquid chromatography method has demonstrated low matrix effects (70%–111%), high sensitivity in terms of limits of quantification (0.005 to 0.3 μg/L), low injection volume (70 nl) and solvent consumption, and the ability to analyze diverse polar and ionic analytes within one run using a single reversed‐phase nanoflow liquid chromatography column. Wastewater samples ( n = 116) from the wastewater treatment plants of different cities in Latvia were analyzed using the developed method. The observed concentrations of biomarkers were in line with the literature data.

The objective of this research was to investigate the feasibility of integrating oat (1 → 3, 1 → 4)-β-D-glucan (β-glucan) dried by two different techniques (freeze drying and spray drying) into a synbiotic formulation with Akkermansia muciniphila. The study evaluated the impact of this synbiotic formulation on the growth of A. muciniphila and its effect on the fermentation process. The extracted oat β-glucans underwent freeze-drying (FD) and spray-drying (SD) processes before being introduced as supplementary carbon sources (1%) to brain heart infusion (BHI) medium containing A. muciniphila MSCL 1582. The BHI medium containing inulin, D-glucose, and BHI without added substrates served as the control. Bacterial growth and short-chain fatty acid (SCFA) production were measured before and after 72 h of fermentation. A light microscope and KOVA slides were used for the A. muciniphila count, and SCFA levels were measured via gas chromatography. Our findings revealed that oat β-glucans could effectively function as prebiotic substrates in complementary synbiotic composition with A. muciniphila, without inhibiting growth and causing metabolic impairment. Both FD and SD techniques demonstrated equivalent and favorable impacts on the fermentative capacity of A. muciniphila, rendering them suitable choices for the drying of β-glucans. Incorporating oat β-glucan into synbiotic formulations offers potential benefits, contributing to A. muciniphila growth and the fermentation process.

It is well known that sheep wool is an agricultural product consumed by the textile industry. However, a large part of this material is frequently wasted due to strict industrial requirements. Considering the cheapness, natural origin, and biodegradability of this product, it was proposed that the wool can be used as an adsorbent for isolation of harmful azo dyes from wastewater. Using genotoxic and mutagenic Congo Red (CR) dye as a model compound, different adsorptive properties of the non-irradiated sheep wool have been studied in an aqueous solution and simulated textile effluent. For the purpose of comparison, the surface of the wool was irradiated with gamma rays up to about 100 kGy absorbed dose and the performance of the obtained samples has been measured. The characterization of the wool surface was based on SEM, BET, FTIR, EPR, and determination of zero-point charge. The adsorptive performance of the samples was compared by constructing and analyzing adsorption isotherms and uptake kinetics curves. It was shown that the CR adsorption on all of the samples followed the Langmuir model and adsorption kinetics was described by the Elovich equation. The non-irradiated sheep wool demonstrated the highest value of saturation adsorption capacity for the CR of 5.7 µmol/g which is comparable to the capacities of a large group of unmodified natural adsorbents. Finally, it was shown that 20 mg of the non-irradiated sheep wool can be used repeatedly without cleaning/regeneration at least three times to isolate the CR from simulated effluent at a concentration of 25 µM.

Quantitative analysis of catecholamines and their acidic metabolites can provide vital information for diagnosis and treatment of various diseases (such as adrenal tumors). However, complicated purification protocols are usually required to isolate the analytes. Molecularly imprinted polymers (MIPs) have attracted considerable attention as a method of selectively separating desired compounds from their matrix. Therefore, we propose a synthetic procedure for new molecularly imprinted sorbents that possess selective binding sites for both catecholamines and their acidic metabolites. The new polymer utilizes non-covalent and semi-covalent imprinting methods. The binding properties of MIPs were evaluated using chromatographic experiments. The results suggest that the MIPs bind with catecholamines much more selectively than with their acidic metabolites. Therefore, increasing sorption selectivity of the acids would make it possible to perform simultaneous extraction of both compound groups.

Simultaneous quantitative analysis of catecholamines (CAs) and their respective acid metabolites in biological fluids can become a powerful tool for diagnosis and treatment of various diseases. However, selective sample preparation procedure is necessary to isolate the aforementioned analytes from the matrix. Therefore, we propose a synthetic strategy for the preparation of a molecularly imprinted sorbent with binding sites for both CAs and their respective acid metabolites. The synthesis combines noncovalent and semicovalent imprinting methods. Methylenebisacrylamide, 4-vynilbenzyl-N,N,N-trimethylammonium (3,4-dimethoxyphenyl)acetate, and 3-phenylpropylacrylate were used as the cross-linker, functional monomer 1/"dummy" template 1, and functional monomer 2/"dummy" template 2 under precipitation polymerization conditions, respectively. The polymer was characterized using Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy. The binding properties were studied by constructing adsorption isotherms and conducting competitive binding tests. The performance of the molecularly imprinted polymers (MIPs) toward CAs and the acids was described by good imprinting factors (3.1-5.6), fast-binding equilibrium, and the ability to differentiate nonmethylated CAs from methylated ones. The MIP was used to simultaneously isolate the analytes from human plasma under dispersive solid-phase extraction conditions with subsequent detection using optimized UHPLC/MS/MS procedure. As a result, no major interferences were detected which suggests that the impurities were well separated from the analytes.

Although the wild parsnip (Pastinaca sativa L. s.L) fruits are known to contain linear and angular furanocoumarins, the individual components of the seeds have not been fully identified and quantitated, and, in the case of immature seeds, reported. In view of this, the main furanocoumarin compounds were extracted using pyridine, and were isolated using semi-preparative high-performance liquid chromatography. The structural elucidation of isolated compounds was done based on detailed spectral analysis conducted by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI/MS), H-1 and C-13 NMR and, where possible, by gas chromatography-mass spectrometry (GC-MS). The quantitative analysis of furanocoumarin compounds in the wild parsnip was conducted by analytical ultra-performance liquid chromatography (UPLC-DAD), calculated against the standard curves of isolated compounds. The total yields of furanocoumarin compounds from the seeds after extraction with pyridine were 107.2-222.8 mg g(-1) (fresh weight) and 50.2-66.4 mg g(-1) (soluble dry matter). Thirteen furanocoumarins were identified. The main compounds (percentage in FW) in immature seeds were bergapten (40.8), pimpinellin (10.5), methoxsalen (5.7), isopimpinellin (4.3), imperatorin (3.2), and phellopterin (7.2). Seven constituents previously not described in P. sativa seeds and its products were identified, namely, byakangelicol (14.4), heraclenin (8.5), isobergapten (2.5), byakangelicin (1.3), heraclenol (0.5), psoralen (0.3), and isobyakangelicin (0.8). The latter is a new compound of the Apiaceae family. Extraction of immature seeds using pyridine gave a much higher yield and a greater variety of furanocoumarins. This indicates that the wild parsnip, along with other Apiaceae family plants, may be an important source of bioactive compounds.

5-Methylcytosine (5-MC) is an important epigenetic modification of DNA. Abnormally high concentrations of this substance appear because of the hypermethylation of cytosine. Therefore, the measurement of the quantity of this compound in mammals is of great importance. Recently, we reported that several imidazolium-based zwitterionic sulfonates form complexes with 5-MC in solution, which can be studied by electrospray ionisation mass spectrometry (ESI-MS). It is shown in this paper that such an association can be utilised for the detection of 5-MC in a DNA sample using high-throughput a flow injection analysis ESI-MS method. A variety of the sulfonate zwitterions have been tested as m/z shift reagents to increase the selectivity of the analysis. It is shown that either of the zwitterions can be used without the loss of sensitivity. The performance of the method was tested in terms of linearity range, sensitivity, intra- and between-day precision and accuracy, matrix effect and carryover. The method described is characterised by simplicity, a good limit of quantitation (1 pg injected) and low run times (at least 50 injections per hour). In addition, high-performance liquid chromatography and tandem mass spectrometry are not required. The possibility exists to widen the scope of the method to other amidine-containing compounds present in more complicated matrices.

This paper describes non-covalent complexes between zwitterionic 3-(1-alkyl-3N-imidazolio)- propane-1-sulfonates and different amines. Electrospray ionization (ESI) mass spectrometry and collision- induced dissociation were used to measure the stability of such complexes in solution and in the gas phase. Generally, zwitterionic sulfonates formed more abundant complexes with protonated 5-methylcytosine (5-MCH) than with aliphatic amines. The results show that the association constants and half-dissociation threshold energies of these complexes nonlinearly depend on the alkyl chain length of the zwitterion. It is shown that the complexes with the lowest stability exist in acetonitrile solution or in the gas phase. The factors responsible for this complicated behavior are discussed. The structure of the complexes was investigated by quantum chemical calculations using molecular mechanics and density functional theory. Hydrogen bonding is proposed as the main type of interaction responsible for the stability of ion-zwitterion complexes. In summary, the information obtained in this study could be used for the development of the new derivatization reagents for some compounds containing amidinium groups, like 5-MCH, to increase selectivity of ESI-based methods.

Reaction of isoniazid with benzoic acid, sebacic acid, suberic acid, and cinnamic acid results in formation of cocrystals. Two polymorphs of isoniazid-suberic acid and two polymorphs of isoniazid-cinnamic acid cocrystals were isolated. Crystal structure analysis shows the presence of a pyridine carboxylic acid synthon in the studied cocrystals. The hydrazide group of isoniazid participates in N-H center dot center dot center dot O and N-H center dot center dot center dot N hydrogen bond formation, producing different supramolecular synthons. The stability study of isoniazid cocrystals has been performed over a 22 week period. A comparison of melting points of isoniazid-dicarboxylic acid 2:1 cocrystals shows the decrease of melting point with an increasing length of the acid. Solubility of isoniazid-carboxylic acid cocrystals tends to increase with increasing solubility of the acid.

Abstract Cereal alkylresorcinols (ARs) are a group of phenolic lipids mainly found in the outer parts of grains of rye and wheat. They have been suggested for use as selective biomarkers for intake of whole grain and bran products of these cereals. Consumption of whole grains and whole grain products has been associated with reduced risk of developing chronic diseases, such as cardiovascular disease, diabetes type 2, obesity and some types of cancer. In this article a sensitive and rapid method of High Performance Liquid Chromatography with UV detection for quantitative determination of ARs in the cereals grown in Latvia is described. Instrument detection limits (IDL) were determined for C17:0, C19:0 and C21:0 homologues (coefficient of variation < 3%). According to the results of these studies, ARs were found in rye (87.1-112.0 mg/100 g), wheat (24.0-40.2 mg/100 g), triticale (32.1-74.4 mg/100 g), and in small amounts in barley (2.2-3.7 mg/100 g), but not in oats.

Gas-phase chemical properties of several (1-methylimidazol-3-io)-alkane-1-carboxylates (alkane=ethane, propane and butane) have been investigated in this study. These substances are synthesized using classical transformations and analyzed in positive ionization mode using collision-induced dissociation (0-50 eV). These experiments were carried out in both deuterated and undeuterated solvent media. The data obtained in this study show, that carboxylate group weakly influences fragmentation of zwitterionic imidazolium carboxylates in positive electrospray mode. On the other hand, these compounds exert a tendency to form various adducts with sodium and potassium ions and to participate in hydrogen/deuterium exchange in the gas phase.

The mass spectrometric properties of several (1,2-dimethyl-1H-imidazol-3-ium-3-yl)-alkane-1-sulfonates (alkane=ethyl, propyl and butyl) are investigated in this study. These substances, named zwitterionic liquids (ZILs), were synthesized using classical transformations and analyzed in positive and negative electrospray ionization mode using collision-induced dissociation (0-50 eV). We have also performed regioselective deuterium labeling of the alkyl chain of 3-(1,2-dimethyl-1H-imidazol-3-ium-3-yl)-propane-1-sulfonates. Thus, the mass spectra of isotopically-labeled compounds were used for the confirmation of fragmentation pathways of ZILs. Briefly, the data obtained in this study show that the fragmentation of ZILs is dependent on the alkyl chain length between the imidazolium ring and the sulfonate group. In positive electrospray mode, the main fragments are the imidazolium ring containing even electron ions. On the other hand, in negative electrospray mode, sulfur-containing radical-anions are dominant.

Liquid Chromatography - Mass Spectrometry of Zwitterionic Liquids We have implemented full mass spectrometric assay of several 3-(1-alkyl-2-methylimidazolio)propanesulfonates, which are known as zwitterionic liquids (ZILs). Hydrophilic interaction liquid chromatography (HILIC) column and different mobile phases in both isocratic and gradient elution conditions were used for separation of the compounds present in these samples. The structures of the impurities have been confirmed by LC-MS/MS experiments. In addition, fragmentation pathways of ZILs were studied for different collision energies (0-50 eV) in positive electrospray ionization (ESI) mode under collision-induced dissociation conditions. Several new routes of fragmentation are briefly discussed. These include possible rearrangements and imidazolium ring expansions, which hypothetically proceed through carbocationic intermediates in the gas phase. Currently these processes are studied in a more detailed fashion. Cviterjonu Šķidrumu Hromatogrāfija-Masspektrometrija Veiktie hromatogrāfiskie pētījumi parāda, ka cviterjonu šķidrumu (CJŠ) un tajos esošo galveno piemaisījumu atdalīšanai acetonitrilu saturošās kustīgās fāzes ir piemērotākas par eluentiem, kuros ir metanols. Lietojot eluenta gradientu, ir iespējams analīzi veikt ātrāk, kā arī uzlabojas hromatogrāfisko joslu forma. AEŠH apvienojumā ar masspektrometriju ļauj noteikt piemaisījumus CJŠ, kā arī noskaidrot to fragmentēšanās maršrutus pat, ja šo piemaisījumu struktūra ir visai līdzīga. Galvenie jonu veidošanās ceļi ietver lādiņa inducēto disociāciju, ja sadursmju energija ir maza, un homolītisko alkilķēdes šķelšanos, ja sadursmju energija ir augsta. Augstas sadursmju energijas gadījumā novēro parādības, ko nosaka karbkatjonu īpašības gāzes fāzē; tās ietver secīgas cikla paplašināšanās stadijas, ko veicina ūdeņraža pārnese. Tomēr pilnīgai fragmentēšanās mehānismu noskaidrošanai nepieciešami jonu masu mērījumi ar augstu precizitāti vai eksperimenti ar izotopus saturošiem savienojumiem.