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Metanephrine (MN) and normetanephrine (NMN) are critical biomarkers for neuroendocrine tumors (pheochromocytoma and paraganglioma). Following our previous development of a molecularly imprinted solid-phase extraction (MISPE) sorbent for urine analysis, this study evaluated MISPE coupled with HILIC-MS/MS for determining metanephrines in human plasma. Unlike conventional phases, the novel polymer selectively binds analytes as in situ-generated anions via quaternary alkylammonium groups in hydroxide form, ensuring accurate extraction from just 25 µL of plasma. Validated per U.S. FDA guidelines, the assay showed good intra- and interday precision (CV < 10.8%), accuracy (bias < −10.6%) and excellent linearity (R² > 0.99) across pathological ranges (184.3–877.8 ng/L for MN; 174.8–923.0 ng/L for NMN), with low relative standard errors (<6.9%). Excellent selectivity was demonstrated in the presence of structurally close analogs (catecholamines, DOPA and its derivatives). Compared with commercial WCX, the sorbent yielded cleaner extracts, significantly reducing the phospholipid interference. Although lower limits of quantification (92.2 ng/L MN; 87.4 ng/L NMN) slightly exceeded healthy upper thresholds, the method has potential for use in specific clinical scenarios with pronounced biomarker elevations: diagnosis of pheochromocytoma/paraganglioma, monitoring post-treatment metanephrine decline, and tracking tumor-induced hypertensive crises in emergencies. This accessible protocol forms a solid foundation for advanced diagnostics.

Catecholamines are important hormones and neuromediators in the human body. Simultaneous determination of both catecholamines and catecholamine metabolites in bodily fluids can help accurately diagnose dangerous health conditions like adrenal tumors. However, the biggest obstacle is the selective separation of these compounds from the biological matrix. In this work, we propose a novel, dual‐recognition, non‐covalent molecularly‐imprinted polymer that utilizes strong anion exchange as the source of sorbent‐analyte interaction. (4‐Vinylbenzyl)trimethylammonium‐homovanillyl alcohol anion salt and (4‐vinylbenzyl)trimethylammonium‐homoveratric acid anion salt served as template/functional monomer complexes for catecholamines and acidic metabolites, respectively. The sorbent was synthesized using precipitation polymerization and studied with batch adsorption experiments, scanning electron microscopy, Fourier‐transform infrared spectroscopy, and Brunauer–Emmett–Teller surface area and pore size analysis. The polymer was loaded into cartridges and tested with acidified urine samples. The analytes are deprotonated and adsorbed via sorbent's tetraalkylammonium moiety in hydroxide form, which also neutralizes excess acid, removing the need for pH readjustment (which is often necessary for urine analysis). The imprinted sorbent can also be reused at least four times without performance deterioration. Norepinephrine, epinephrine, dopamine, normetanephrine, metanephrine, vanillylmandelic acid, and homovanillic acid were separated and analyzed in a single run using molecularly imprinted solid‐phase extraction combined with liquid chromatography‐tandem mass spectrometry (MISPE‐LC‐MS/MS), with recoveries ranging from 69% (epinephrine) to 97% (homovanillic acid). Method's limits of detection, limits of quantitation, linearity, repeatability, trueness, and intermediate precision were evaluated. Limits of quantitation ranged from 0.7 to 6.5 µg/L (for catecholamines and metanephrines) and from 0.12 to 0.2 mg/L (for acidic metabolites). Compared to commercially available weak‐cation exchange and hydrophilic‐lipophilic balance cartridges, the imprinted sorbent produced stronger catecholamine signals with minimal volume of urine (25 µL). This study successfully demonstrated molecularly imprinted solid‐phase extraction workflow for simultaneous separation and quantitation of urinary catecholamines and their basic and acidic metabolites, proving its compatibility with bioanalysis.

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.

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.

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.

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. Graphical Abstract

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-3 N-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.

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.