Electron Ionization Research Articles

Confirmation of Solid Phase Extracted Post‐Blast Explosives Residues Analyzed Using Pulsed Split Injection GC/MS

AbstractA pulsed split injection method was developed for the improved detection of explosives using gas chromatography with mass spectrometric detection (GC/MS) with negative chemical ionization for 12 organic explosives (nitramines, nitrate esters, nitroalkanes, nitroaromatics) and electron ionization with selected ion monitoring for triacetone triperoxide (TATP). An order of magnitude increase in signal (average factor of 13) was observed for all organic explosives with the utilization of the pulsed split injection for samples processed by solid phase extraction (SPE). The method was successfully applied to post‐blast explosives residue processed by SPE and syringe filtration as a confirmatory technique following gas chromatography with electron capture detection (GC/ECD) screening. Compared to current methodologies previously reported, a decrease in the false screen rate (the number of compounds that passed the screening criteria, but not confirmed present) was achieved when employing this method. Processing of post‐blast explosives samples using SPE decreased the false screen rate from 60% to 34%, while using syringe filtration decreased the false screen rate from 73% to 51%.

Possibility of identifying 1H-indolylaminium trifluoroacetates with antimicrobial activity by mass spectrometry

The present study proposes a convenient approach to identify a series of novel substituted 1H-indol-5-,6-ylaminium trifluoroacetates with antimicrobial activity based on mass spectral data obtained using direct injection into an ion source at an elevated temperature when the salts decompose with the release of counterions: acids and organic bases – substituted 1H-indolylamines. By the presence of ions with m/z 69, 45, 28, 17 in the spectra, it is judged that the salts are formed by trifluoroacetic acid. Using the available literature data on the mass spectrometry of substituted indoles, aromatic amines, and carboxylic acids, substantiated schemes for the decomposition of molecular ions of organic bases, 1H-indolylamines, are compiled and discussed, in which the mechanism of formation and the structure of fragment ions arising under electron ionization conditions are given. The revealed general, as well as individual for individual representatives with a certain character and place of substitution in the indole bicycle, patterns of behavior of 1H-indolylamine radical ions under conditions of high-temperature mass spectral imaging make it possible to judge their structure and, in general, the structure of 1H-indolylamine trifluoroacetates. The approach used in this work can also be used to prove compounds of a similar group based on the analysis of their mass spectra.

Band Diagram Insights into the Kinetic and Thermodynamic Engineering of Tandem Photocatalytic Cells.

In this work, we theoretically investigate the impact of kinetic and thermodynamic properties on the performance of photocatalytic cells operating in an unassisted tandem configuration, including electron affinity and ionization energies, recombination rates, and reaction rates. To this end, we present general rules and metrics for identifying and isolating the origin of an observed shift in the onset potential at either the photoanode or the photocathode of these devices. The correlation between kinetic and thermodynamic shifts in the onset potential is demonstrated through the use of band diagrams and key comparable features within readily accessible characterization tools: current-voltage plots are taken both under illumination and in the dark and further coupled with Mott-Schottky plots. To illustrate this conceptual framework, a model system comprised of a p-type doped BiVO4 photocathode and an n-type doped BiVO4 photoanode is employed. By varying each of the aforementioned kinetic and thermodynamic parameters in isolation, the manner in which these various mechanisms shift the onset potential is demonstrated. This work intends to showcase how kinetic and thermodynamic effects are distinctly manifested in these commonly used characterization tools and further proposes thermodynamic band-edge engineering as a potentially useful and largely unexplored avenue for possibly improving tandem cell performance, in addition to the conventional approach of optimizing kinetics.

Determination of Synthetic Opioids Belonging to the Fentanyl Class in Silt Using Electron Ionization Gas Chromatography-Mass Spectrometry (GC-MS).

An extraction protocol from silt sediment of fentanyl and three analogs: acetylfentanyl, thiofentanyl and acetylthiofentanyl, spiked at two concentrations each and separately (at ∼1 and ∼10 µg/g), is described. In addition, the identity of the fentanyls preliminarily identified by electron ionization gas chromatography-mass spectrometry (EI-GC-MS) analysis, can be corroborated by reacting each opioid in the silt’s extract with 2,2,2-trichloroethoxycarbonyl chloride (Troc-Cl). Reaction between Troc-Cl and each opioid generates two unique products that can be used to retrospectively identify the original opioid therefore serving as a corroborating tool for known opioids as well as new, unknown fentanyl analogs.

Structure and Electronic Properties of the A‐center in Si1−xGex Alloys: Insight from the Heyd–Scuseria–Ernzerhof Hybrid Functional Calculations

This study investigates the structure and electronic properties of the A‐center in Si1−xGex alloys (x = 0, 0.25, 0.50, 0.75, and 1), using the Heyd–Scuseria–Ernzerhof hybrid functional. It is found that the most stable structures form SiOSi bonds, with the other two atoms surrounding the A‐center being Ge atoms, which form a long bond between them. The behavior of the O atoms is significantly influenced by the Ge content. As it increases, the position of the O atom shifts relative to the surrounding atoms, thereby affecting the bond lengths and angles. The formation energy of the A‐center first decreases with increasing Ge content up to 0.75, which enhances the defect production; however, then it decreases from 0.75 to 1, thus suppressing defect production. The calculations are consistent with the experimental data, showing that the distance of the defect level from the conduction band minimum increases with Ge content, supporting the observed enthalpy changes in electron ionization.

Research on a miniature Mattauch-Herzog mass spectrometer designed for space exploration

Mass spectrometers have gained increasing importance in recent space missions. This paper presents the development of a miniature Mattauch-Herzog mass spectrometer for mass analysis. The mass spectrometer consists of an electron ionization (EI) source, an electrostatic and magnetic mass analyzer, and a focal plane detector. The construction of the EI source is based on a study of the impact of electrode voltages on ion focusing performance and ion transmission efficiency using the phase space method in the SIMION-8.1 software. The SIMION model of the mass analyzer is utilized to analyze the effects of electrostatic field voltage and magnetic fringe field on the ion beam. Experimental results from the instrument prototype demonstrate that the ion beam is influenced by the electrostatic field in a manner consistent with the simulation results of the SIMION model. The theoretical mass-to-charge ratio range of this double focusing mass spectrometer (DFMS) is 8amu–300amu, and it is capable of distinguishing isotopes with mass differences larger than 0.3amu, such as Ne. The N2 peak width at Full Width Half Maximum (FWHM) is 0.4amu, the mass resolution is 70.0, and the minimum detectable pressure of N2 is 2.8 × 10−9Pa. The Xe peak width (FWHM) is 1.3amu, the mass resolution is 101.5, and the minimum detectable pressure of Xe is 4.4 × 10−9Pa.

Ethanolamine ices: Experiments in simulated space conditions

Laboratory experiments on the interactions between complex organic molecules, interstellar dust, and ultraviolet (UV) radiation are crucial to understanding the physicochemical mechanisms that lead to the synthesis of the observed interstellar complex organic molecules (iCOMs), and to search for new molecular species not yet observed in the gas phase of the interstellar medium (ISM). We aim to study the role of a new, recently discovered interstellar molecule, ethanolamine (EtA, NH CH CH OH), in surface chemistry in the ISM. In the laboratory, thanks to a combination of temperature programmed desorption (TPD) experiments and electron ionization (EI) mass spectrometry analyses, we studied the thermal desorption of pure ethanolamine and its mixture with water from nanometric amorphous olivine grains cooled down to 10 K, with or without UV irradiation. Ethanolamine was found to be stable, even in the presence of water, when irradiated with UV light. The presence of olivine grains strongly modified the TPD curves, trapping the molecule up to about 295 K, meaning that the precursors of some biological molecules could be retained on the grains even in the innermost parts of protoplanetary disk. We then identified a series of products formed when the molecule was irradiated onto the dust substrate. Of particular interest is the fact that irradiation of ice containing ethanolamine, a molecule known to be present in the ISM, can produce more complex and astrobiologically interesting species. Furthermore, our results further our understanding of existing observational data.

A comparative study of total and partial ionization cross sections, branching ratios and fragmentation patterns of XH4 (X = C, Si, Ge, Sn, Pb)

The formation and decomposition of SnH4 has been recently reported using electron ionization mass spectrometry (J. Am. Soc. Mass Spectrom. 35 (2024) 1523 and J. Vac. Sci. Technol. A 41 (2023) 063209) due to its importance in tin contamination cleaning in extreme ultraviolet lithography. A comprehensive understanding of the fragment patterns of SnH4 requires total and partial ionization cross sections of SnH4. However, there is limited availability of experimental and theoretical ionization data for SnH4. We report the electron-impact ionization fragmentation patterns of XH4 (X = C, Si, Ge, Sn, Pb) and should provide missing data, especially for SnH4 and PbH4. Total ionization cross sections are calculated using the Binary Encounter Bethe (BEB) method. Partial ionization cross sections and branching ratios are determined using mass spectrum data (MSD) and Huber et al’s method. Finally, we compare the calculated percentage abundances for the fragments of XH4 with experimental measurements.

A-316 A quantitative gas chromatography tandem mass spectrometry method for metabolic profiling of urine organic acids and acylglycines

Abstract Background The analysis of urine organic acids (UOA) and acylglycines (UAG) are an essential investigation for the diagnosis inborn errors of metabolism (IEMs). The vast majority of methods for these analytes use gas chromatography mass spectrometry (GC-MS) and are only qualitative. Gas chromatography tandem mass spectrometry (GC-MS/MS) offers greater sensitivity and selectivity and enables the combination of qualitative screening with quantitative analysis. We describe the development and validation results of a quantitative GC-MS/MS method. Methods Urine creatinine concentrations were measured (CobasPro, Roche Diagnostics) and normalized to 1.25 mmol/L. After internal standard addition, each urine specimen, calibration standard and QC were incubated with a hydroxylamine solution followed by a liquid-liquid extraction. Further sample concentration permitted the isolated UOA and UAG to be derivatized using N,O-bis(trimethylsilyl)trifluoroacetamine (BSTFA) with 1% chlorotrimethylsilane (TMCS) prior to injection. GC-MS/MS analysis was performed using a GC-MS-TQ8050 triple quadrupole system (Shimadzu) with a 30 m DB-5MS (Agilent J&W) capillary column (0.25 mm, ID of 0.25 µm). Split injection mode was deployed with an initial column temperature of 70°C. The mass spectrometer was operated in electron ionization (EI) and multiple reaction monitoring (MRM) modes. Results The optimal temperature gradient for high-resolution UOA and UAG separations was derived and their respective retention times determined. MS/MS detection parameters were optimized to permit the identification of precursor and production ions for all (N=36) derivatized analytes. Total analysis time was 33.8 min per injection. This method permits the measurement of 11 samples in one batch and is highly linear for all analytes (R^2 >0.99 and average slope 1.04). The limit of quantification (LOQ) was established and ranged from <0.05 to 2.1 µmol/mmol creatinine. Intra- and inter-day imprecision (CV%) was determined using matrix-matched abnormal and normal QC. Intra-day imprecision (N=10) ranged from 1.3% (2-ketoglutaric acid) to 9.7% (3-hydroxybutyric acid). Inter-day imprecision (N=30 over 15 days) ranged from 2.2% (ethylmalonic acid and methylmalonic acid) to 20.5% (3-hydroxy-3-methylglutaric acid). The method had an average accuracy of 113±14% for analytes included in the ERNDiM quantitative organic acids (urine) external quality assurance program. For analytes not included in this proficiency testing, the method showed good agreement when compared to a national reference laboratory, with average Deming correlation coefficients and regression slopes being 0.9944 and 1.1, respectively. No interferences were detected when monitoring the analyte quantifier and qualifier ion ratios in patient urine. Conclusions The devised GC-MS/MS protocol permits the unbiased identification and quantification of UOA and UAG used to investigate IEMs. The method has acceptable sensitivity, specificity, precision and accuracy for clinical routine clinical testing.

FederEI: Federated Library Matching Framework for Electron Ionization Mass Spectrum Based Compound Identification.

Mass spectrometry (MS) is a powerful tool for compound structure elucidation, crucial in various domains including pharmaceuticals, chemical synthesis, environmental analysis, and metabolomics. Compound identification via spectral matching relies heavily on reference libraries, yet existing universal libraries may lack comprehensiveness. Laboratories often create their own libraries, leading to fragmentation within the scientific community. Addressing this, we propose FederEI, a federated library matching solution for EI-MS-based compound identification. FederEI enables decentralized compound identification while preserving data privacy, achieved through a server-to-server connection framework. Each laboratory retains control over its spectral data, enhancing privacy and minimizing data transmission. FederEI integrates a fast and accurate library matching algorithm, offering comparable performance to local matching while maintaining data security. Evaluation against the classic approach demonstrates FederEI's effectiveness, ensuring robust compound identification.

One Pot Synthesis of Thiopyrimidine Derivatives from Lignin Reproductions by Microwave-Assisted Ultrasonic Microscopy with DFT Description for Clarifying the Mass Spectrum

In this work, an efficient and sustainable procedure for the one-pot synthesis of thiopyrimidine derivatives starting 1,3-diketone cut off β-O-4 lignin precursors to create anticancer agents. Microwave-ultrasonic assisted lignin extract in accessing various heterocyclic precursors such as pyrimidine, pyridine, and thiophene moieties. The results designated the ultrasonic-assisted microwave significantly accelerated synthesis with reduced time. We have diversely prolonged to tight-binding approaches to the electron ionization mass spectrometry with quantum stimulation (DFT/EIMS) to examine electron ionization mass spectra correlated to the experiment. Moreover, DFT/EIMS provides into the mechanism of the reaction of mass spectra trials. It cabins on the fragmentation method to raise the challenging bond breaking and structural rearrangements. The quantum chemical process for effective precursors of a mass spectrum is exactness required and discussed. Foremost fragmentation designs are studied and related to experimental data of the pyrimidin-thione derivatives and their glycosides.

Exploring the pyrolytic degradation of seventeen phthalate esters using the non-targeted regions of interest-multivariate curve resolution (ROIMCR) chemometric method

The global use of phthalate esters (PAEs) in plastic production entails a need for developing effective remediation strategies to minimize exposure and health risks. In this study, pyrolysis degradation processes are evaluated for 17 different PAEs that were analyzed by high-resolution gas chromatography-mass spectrometry (Pyr-GC-Orbitrap-MS) at different temperatures (300 °C, 400 °C, 500 °C, 600 °C, 700 °C, 800 °C) both in electron ionization (EI) and positive chemical ionization (PCI) mode. All the analytical data generated have been processed with the Regions of Interest Multivariate Curve Resolution (ROIMCR) chemometrics method. A preliminary selection of the Mass Spectrometry Regions of Interest (ROIs) coupled to a bilinear factor decomposition method (MCR-ALS) allowed the identification of 4 principal components, which were used to define the thermal degradation process. ROIMCR method is a powerful tool for non-targeted analysis which allows the resolution of the elution and spectral profiles of the different constituents present in the analyzed samples, which were confirmed using PCI. Moreover, ROIMCR was used to resolve and identify the different products generated during the studied degradation processes. As a result, 10 new thermal degradation products were identified in the analysis of the different sample sets. Finally, the degradation efficiencies higher than 99.8 % were obtained for all the PAEs at 800 °C, except for benzoic acid-benzyl ester, whose removal efficiency decreased to 94.8 %. As phthalates are widespread and toxic compounds for the environment and for humans, there is a need for new remediation technologies. This study provides new knowledge to understand their elimination through thermal processes. We combine mass spectrometric data with powerful chemometric processing to determine the removal efficiency, to understand the degradation process and to identify the degradation compounds formed through thermal decomposition.

A comparative study of optical property on unintentionally doped and Sn-Doped β-Ga2O3 crystals by EFG method with a cylindrical Ir die

In this work, we carried out a comparative study of optical property on unintentionally doped and Sn-doped β-Ga2O3 crystals by edge-defined film-fed growth (EFG) method with a cylindrical iridium (Ir) die. The non-polarized Raman spectra showed the anisotropy in Raman peak position and intensity for three different planes (i.e., (100), (010) and (001)) of β-Ga2O3 crystals, independent of the Sn dopant. A difference in the Raman spectra between the unintentionally doped and Sn-doped β-Ga2O3 crystals was observed in the (001) plane. The strong in-plane anisotropy of the monoclinic β-Ga2O3 crystal related to the crystallographic orientation was demonstrated by the angle-resolved polarized Raman spectroscopy. The Sn dopant cannot change the optical transmittance and bandgap values of the unintentionally doped and Sn-doped β-Ga2O3 crystals with the (100), (010) and (001) orientations. However, the Sn-doped β-Ga2O3 crystal with the (010) orientation showed the higher valence band maximum and lower surface barrier height values. The X-ray photoelectron spectroscopy of the unintentionally doped and Sn-doped β-Ga2O3 crystals with the (010) orientation was also measured, which showed no obvious difference. The different luminescence centers and level of electron ionization of the unintentionally doped and Sn-doped β-Ga2O3 crystals were observed by the cathodoluminescence spectroscopy and electron paramagnetic resonance, respectively. Based on the comprehensive comparison, it can be concluded that the anisotropy in optical property of the unintentionally doped and Sn-doped β-Ga2O3 crystals with (100), (010) and (001) orientations apparently exist.

Improved Discrimination of Mass Spectral Isomers Using the High-Dimensional Consensus Mass Spectral Similarity Algorithm.

This study employs a high-dimensional consensus mass spectral (HDCMS) similarity scoring technique to discriminate isomers collected using an electron ionization mass spectrometer. The HDCMS method was previously introduced and applied to the discrimination of mass spectra of constitutional isomers, methamphetamine and phentermine, collected with direct analysis real-time mass spectrometry (DART-MS). The method formulates the problem of discriminating mass spectra in a mathematical Hilbert space and is hence called "high dimensional." It requires replicate mass spectra to build a Gaussian model and evaluate the inner products between these functions. The resulting measurement variability is used as a signature by which to discriminate spectra. In this work, HDCMS is tested on electron impact ionization (EI) mass spectra of 7 terpene and terpene-related (C10H16 and C10H14) isomers with experimental retention indices that differ by less than 30 and with traditional cosine similarity scores greater than 0.9, on a scale of 0 to 1, when compared with at least one other compound in the test set. Using identical instrument parameters, 15 replicate gas chromatography-electron ionization-mass spectrometry (GC-EI-MS) spectra of each isomer were collected and separated into distinct library and query sets. The HDCMS algorithm discriminated each isomer, indicating the method's potential. Because the method requires replicate measurements, observations from a simple heuristic study of the number of replicates required to discriminate these isomers is presented. The paper concludes with a discussion of compound discrimination using HDCMS and the benefits and drawbacks of applying the method to EI-MS data.

A Dibenzo[g,p]chrysene‐Based Organic Semiconductor with Small Exciton Binding Energy via Molecular Aggregation

AbstractExciton binding energy (Eb) is understood as the energy required to dissociate an exciton in free‐charge carriers, and is known to be an important parameter in determining the performance of organic opto‐electronic devices. However, the development of a molecular design to achieve a small level of Eb in the solid state continues to lag behind. Here, to investigate the relationship between aggregation and Eb, star‐shaped π‐conjugated compounds DBC‐RD and TPE‐RD were developed using dibenzo[g,p]chrysene (DBC) and tetraphenylethylene (TPE). Theoretical calculations and physical measurements in solution showed no apparent differences between DBC‐RD and TPE‐RD, indicating that these molecules possess similar properties on a single‐molecule level. By contrast, pristine films incorporating these molecules showed significantly different levels of electron affinity, ionization potential, and optical gap. Also, DBC‐RD had a smaller Eb value of 0.24 eV compared with that of TPE‐RD (0.42 eV). However, these molecules showed similar Eb values under dispersed conditions, which suggested that the decreased Eb of DBC‐RD in pristine film is induced by molecular aggregation. By comparison with TPE‐RD, DBC‐RD showed superior performances in single‐component organic solar cells and organic photocatalysts. These results indicate that a molecular design suitable for aggregation is important to decrease the Eb in films.

A Dibenzo[g,p]chrysene-Based Organic Semiconductor with Small Exciton Binding Energy via Molecular Aggregation.

Exciton binding energy (Eb) is understood as the energy required to dissociate an exciton in free-charge carriers, and is known to be an important parameter in determining the performance of organic opto-electronic devices. However, the development of a molecular design to achieve a small level of Eb in the solid state continues to lag behind. Here, to investigate the relationship between aggregation and Eb, star-shaped π-conjugated compounds DBC-RD and TPE-RD were developed using dibenzo[g,p]chrysene (DBC) and tetraphenylethylene (TPE). Theoretical calculations and physical measurements in solution showed no apparent differences between DBC-RD and TPE-RD, indicating that these molecules possess similar properties on a single-molecule level. By contrast, pristine films incorporating these molecules showed significantly different levels of electron affinity, ionization potential, and optical gap. Also, DBC-RD had a smaller Eb value of 0.24 eV compared with that of TPE-RD (0.42 eV). However, these molecules showed similar Eb values under dispersed conditions, which suggested that the decreased Eb of DBC-RD in pristine film is induced by molecular aggregation. By comparison with TPE-RD, DBC-RD showed superior performances in single-component organic solar cells and organic photocatalysts. These results indicate that a molecular design suitable for aggregation is important to decrease the Eb in films.

Synthesis and Density Functional Theory Study on the Functionalization of Carbon Nanotube Conjugates with Amino Compounds and Their Application in Dyeing Processes

AbstractThis study investigates the functionalization of graphene nanotube (GNTs) conjugates with an amino compound called 1‐amino‐2‐hydroxy‐4‐naphthalene sulfonic acid (AHNSA‐GNTs). The study also evaluates the potential application of these conjugates in dyeing processes. The goal is to modify GNTs to enhance their interaction with dyes, thus improving the efficiency of dyeing textiles and the colorfastness of the resulting products. Multiple characterization methods, such as X‐ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to get a better look at the composites. The findings of the study indicate that AHNSA‐GNTs composites improve dye retention on wool fibers, which leads to a reduction in the consumption of excess dye and water. Density Functional Theory (DFT) calculations were utilized to investigate the electronic properties and binding energies of the functionalized CNTs, providing insights into the molecular interactions between the CNTs and amino compounds. Overall, this study highlights the promising applications of graphene nanotubes in sustainable textile processes. Frontier molecular orbitals (FMOs) and global reactivity descriptors serve as key tools for understanding the stability and chemical reactivity of compounds. These tools were used to calculate FMOs and electronic parameters of compounds 1 and 2 at the B3LYP/6‐31G(d) level of theory. The study examined the highest occupied molecular orbital (HOMO)‐lowest unoccupied molecular orbital (LUMO) energy gap, which provides insights into molecular stability and reactivity. Various physical properties were derived from these calculations, including electron affinity (EA) and ionization potential (IP) to LUMO and HOMO energies. Compound 2 emerged as the most efficient electron donor, possessing the highest HOMO energy, while compound 1 excelled as the best electron acceptor with the highest LUMO energy.

Thermodynamics of gaseous strontium and calcium cerates studied by Knudsen effusion mass spectrometry and estimation of relative electron ionization cross-section for CeO2(g).

Ceria-based systems are of great interest because of their unique properties. Such systems may be used as anode materials for SOFCs or in oxygen sensors. Theexploitation of these materials often requires high temperatures. In such conditions, the partial or complete evaporation of materials is possible. Therefore, knowledge of the values of partial pressures and thermodynamic properties is essential to predict and/or prevent possible consequences and accidents. Knudsen effusion mass spectrometry was used to determine partial pressures of vapor species over the SrO-CeO2 and CaO-CeO2 systems. Measurements of partial pressures were performed with a MS-1301 mass spectrometer. Vaporization was carried out using molybdenum or tungsten effusion cells. A theoretical study of gaseous strontium and calcium cerates was performed by several quantum chemical methods: density functional theory (DFT) M06, DFT PBE0, and MP2. The minimum value of relative electron ionization cross-section for CeO2 was estimated. In the temperature range of 2218-2249 K above the SrO-CeO2 system and of 2128-2208 K above the CaO-CeO2 system, gaseous M, MO, MO, CeO2, O, O2 and MCeO3 (M = Sr, Ca) were found. Energetically favorable structures of gaseous SrCeO3 and CaCeO3 were found, and vibrational frequencies were evaluated in the "rigid rotor-harmonic oscillator" approximation. On the basis of the equilibrium constants of gaseous reaction MO + CeO2 = MCeO3, the standard formation enthalpy of gaseous SrCeO3 (-913 ± 26 kJ/mol) and of gaseous CaCeO3 (-917 ± 26 kJ/mol) at 298 K were determined. The estimated value of relative electron ionization cross-section for CeO2 is in agreement with the general rule applicable for dioxides. The stability of SrCeO3 and CaCeO3 gaseous species was confirmed by KEMS. Gas-phase reactions involving gaseous SrO (CaO) and CeO2 with gaseous SrCeO3(CaCeO3) were studied. Enthalpy of formation reaction of gaseous SrCeO3(CaCeO3) from gaseous SrO (CaO) were evaluated theoretically, and the obtained value is in agreement with the experimental one.

Skin derived branched‐chain fatty acids in fetal horse gut

AbstractBranched‐chain fatty acids (BCFAs) are mostly saturated fatty acids with a methyl branch at the penultimate or antepenultimate position to the CH3 end. Very‐long‐chain BCFAs (C ≥ 20) are uniquely found in surface lipids. Human and California sea lion (Zalophus californianus) are the only two species that possess vernix at birth, and vernix particles carry loads of BCFA to the gut, potentially influencing the establishment of the first microbiota. Horse (Equus caballus) contains high levels of BCFA in its surface lipids, and the current study aims to investigate if BCFA are components of a neonatal foal's gut. Electron ionization tandem mass spectrometry was used to distinguish iso‐ and anteiso‐form of BCFA from straight‐chain fatty acids. Abundant very‐long‐chain iso‐BCFA, mainly even‐numbered iso‐20:0, iso‐22:0, iso‐24:0, and iso‐26:0 were found in horse meconium but not in their manure collected a few months later. There are little differences in BCFA types and concentrations between foal manure and adult manure. Moderate to high levels of very‐long‐chain anteiso‐BCFA were also found. Comparisons of horse meconium BCFA to horse skin cholesterol ester BCFA content and to meconium from human and sea lion suggest its skin derived origin. The study expands our knowledge on the gut nutritional environment of a newborn horse, and further study is needed to establish the relationship between gut BCFA and microbiota composition in the first few hours of life.Practical Applications: Branched‐chain fatty acids (BCFA) are bioactive compounds found in vernix caseosa, the lipid‐laden material covering the surface of a newborn baby. BCFA also reaches high concentrations from the third trimester of gestation until birth. However, the exact functionality and mechanisms of BCFA in the surface and gut of a fetus remain unclear. The current study aims to clarify the lipid conditions in the gut of newborn foals and to identify the associations between BCFA in the gut and on the skin at a critical point when the horse's microbiota establishes itself. The findings of the current study lay a path for studying the physiological functions of BCFA in horse models, potentially accelerating research related to BCFA.

Study of the amino acid composition of Chimáphila umbelláta herb

The therapeutic use of amino acids is a promising direction of modern pharmacy and medicine. Amino acids play an important role in the complex pharmacological action of herbal medicines, and also improve the assimilation of other biologically active substances (BAS) and are able to potentiate their pharmacological activity. A sufficiently rich source of amino acids are medicinal plants that combine in their composition a complex of groups of BAS, thanks to which they have a combined effect on the body The purpose of the work was the study the amino acids of Chimáphila umbelláta herb with the aim of expanding the knowledge about the chemical composition of the herbal raw material and the development of a phytotherapeutic agent with nephroprotective and anti-inflammatory properties in the future. The object of the study was Chimáphila umbelláta dried herb (supplier «World of Herbs», Kharkiv). The research was performed by gas chromatography-mass spectrometry using a SHIMADZU GC-MS-QP2010 chromatographic system connected to an electron ionization ion source and a single-quadrupole MS 5975C (Shimadzu Technologies). A robotic autosampler and a split/non-split injection port were used. The separation of amino acids was carried out in an Rxi-5 ms (capillary column of Restek Corporation – length 30 m, outer diameter 0.25 mm and thickness liquid–stationary phase 0.25 μm) with a liquid stationary phase of 5% diphenyl and 95% polysiloxane, with helium at purity 99.99% as a carrier gas at a constant flow of 1.47 ml/min. Standard mixtures of L-amino acids: alanine, serine, valine, threonine, leucine, isoleucine, proline, aspartic acid, glutamic acid, lysine, methionine, phenylalanine, and tyrosine (Sigma-Aldrich GmbH, Steinheim, Germany) were used for the analysis. Amino acids were identified by comparing the mass spectra of compounds with data from the NIST14 and WRT10 libraries, and a mixture of standard samples was used to identify and quantify amino acids. The content of 7 amino acids, of which 3 are essential amino acids (L-valine, isoleucine, L-leucine) were identified in Chimáphila umbelláta herb. The largest amount contains L-glutamic acid (14.469 µg/g), the smallest – L-leucine (0.050 µg/g). The obtained results are important in the development of a phytotherapeutic agent for use in diseases of the kidneys and urinary tract. The amino acids identified in the studied raw materials play an important role, so L-glutamic acid participates in protein and carbohydrate metabolism, stimulates oxidation processes, helps detoxify and remove ammonia from the body, increases the body’s resistance to hypoxia. Alanine has the ability to reduce the risk of developing kidney stones, it is the basis of normal metabolism in the body, helps fight hypoglycemia; helps to moderate fluctuations in blood glucose levels between meals. The content of aspartic acid is also important – the precursor of lysine and the donor of amino groups in the biosynthesis of substitute amino acids. The quantitative content of amino acids in Chimáphila umbelláta herb was studied by the method of gas chromatography-mass spectroscopy. According to the results of the study, the content of amino acids was determined in the following order: L-glutamic acid > L-alanine > L-aspartic acid > L-valine > L-proline > isoleucine > L-leucine. The results of the conducted research indicate a rather high and diverse content of amino acids in Chimáphila umbelláta herb, which can improve the balance of phytoremedies and dietary supplements for the purpose of prevention of deficiency of this class of biologically active substances.