Досліджено якісний склад та кількісний вміст вторинних метаболітів рослин Colobanthus quitensis (перлин- ниці антарктичної) з районів Південних Шетландських островів, Берега Греяма і Берега Данко. Порівняно склад і антиоксидантні властивості екстрактів, вилучених із рослин перлинниці, що зростали на різних локаціях у природному середовищі та в умовах in vitro. Також було зіставлено склад і властивості екстра- ктів перлинниці та екстракту іншої антарктичної рослини — щучнику антарктичного (Deschampsia antarctica). Біохімічний склад екстрактів вивчено методами високоефективної рідинної хроматографії та масспектрометрії з матрично-активованою лазерною десорбцією / іонізацією; антиоксидантні властивос- ті досліджено за допомогою DPPH-тесту. Встановлено, що всі екстракти перлинниці характеризуються високим вмістом фенольних сполук (до 38 мг/г сирої сировини) і виявляють значну антиоксидантну / ан- тирадикальну активність (інгібують до 90 % DPPH радикалів за 30 хв). Показано, що антирадикальна активність досліджених екстрактів корелює із загальним вмістом антиоксидантів у зразках. Екстракти з нативних рослин перлинниці містять в основному флавоноїди (глікозиди апігеніну, лютеоліну та мети- лових ефірів лютеоліну), частка яких становить ~90 % загального вмісту фенольних сполук; інші ~10 % фенольних антиоксидантів складають гідроксибензойні та гідроксикоричні кислоти. В екстракті з куль- тури in vitro, навпаки, переважають фенольні кислоти (~58 %). Біохімічний склад досліджених екстрактів перлинниці відрізняється від складу екстракту щучнику значно більшим відносним вмістом похідних апіге- ніну (16—43 % загального вмісту фенольних сполук проти 3 % у щучнику) та меншим вмістом похідних лю- теоліну (46—71 % проти 79 % у щучнику) і фенольних кислот (9—13 % проти 18 % у щучнику). Порівняно з екстрактом щучнику в досліджених екстрактах перлинниці загальний вміст фенольних сполук нижчий і, відповідно, здатність цих екстрактів інгібувати DPPH радикали менша. Незважаючи на це, Colobanthus quitensis, як і Deschampsia antarctica, також є ефективним продуцентом цінних природних антиоксидантів.

Vacuum-sublimation cryogenic deposition (VS-CD) method is successfully applied to produce fullerene water colloidal solution (FWCS): the melting of the solid phase of the mixture obtained by joint condensation of C60 fullerene and water vapors onto a surface cooled with liquid nitrogen results in formation of a stable colloidal solution. The results of the FWCS characterization by means of Raman, IR, and UV-Vis spectroscopy and their comparison with known literature data on hydrated fullerenes give the authors an opportunity to make conclusion that the FWCS contains C60@{H2O}n complexes of hydrated C60 fullerene. Transmission electron microscopy shows that the VS-CD-produced material contains predominantly small C60 clusters of about 2–5 nm size, while mass spectrometry with laser desorption/ionization has demonstrated the presence of pure fullerene C60 and the absence of any products of its transformation. The performed analysis reveals a close similarity of the stable C60@{H2O}n complexes generated by VS-CD with the previously known highly hydrophilic hydrated fullerene obtained by ultrasonication method.

Electrospun polymeric nanofibers incorporated with some medicines or biologically active nanoparticles have a huge range of various applications in biomedical fields such as wound dressing, drug delivery, and tissue engineering. Blending several polymers with different properties allows one to obtain a new material with improved physicochemical and mechanical characteristics, as well as to control the incorporation and release of medical agents, including antimicrobial, antifungal, and other substances. In this work, a novel approach to prepare a blend of two polymers [polyvinylpyrrolidone (PVP) and polymethyl methacrylate (PMMA)] to produce biocompatible nanofibers with incorporated antibacterial agents — phenylalanine or silver nanoparticles is proposed. The diameter of the obtained nanofibers is in the range of 2–4 μm. Antimicrobial agents are incorporated in PVP in an aqueous solution, then the prepared adduct is dried and mixed with PMMA in an organic solvent. In this nanofiber mat, PMMA provides the mechanical strength of the mat and assists in the gradual release of the antimicrobial agents. The formation of the PVP:PMMA nanofibers with incorporated antimicrobial agents at different stages was monitored by spectroscopy. The release of antimicrobial agents from the nanofibers mat during wetting was studied and confirmed by spectroscopy and mass spectrometry investigations.

It is established that crystalline graphite-like carbon nitride (CGCN) exhibits high photocatalytic activity in the process of chemoselective reduction of furfural to furfuryl alcohol in the presence of co-catalysts under the action of visible light by electron-donating substrates, such as methanol/water and ethanol/water, in an acidic medium. When palladium chloride additives are introduced into the reaction mixture, the rate of the process is higher than with the participation of the Pd/SiO2 co-catalyst. This phenomenon may be due to the in situ formation of the CGCN/Pd0 composite photocatalyst in the presence of PdCl2, where the photogenerated charges are better separated than in the CGCN-Pd/SiO2 system. The effective quantum yield of furfural reduction is 56

Background. Study of properties and intermolecular interactions of biologically active compounds which can be used for the purposes of transmembrane drugs delivery is a topical task of modern molecular biophysics. Ascorbyl Palmitate (AP) as a fat-soluble form of vitamin C has recently attracted attention as a promising agent for formation of nanosomes for the “fat insoluble” drug molecules transfer through membranes. However, AP is not sufficiently characterized by up-to-date soft ionization mass spectrometric techniques. Objectives. The aim of the present work is to characterize AP and its intermolecular interactions by a number of mass spectrometric techniques: Electrospray Ionization (ESI), Laser Desorption/Ionization (LDI) and Matrix-Assisted Laser Desorption/Ionization (MALDI). The comparison of these techniques applicability to the study of AP intermolecular interactions as a drug delivery assisting agent is scheduled. Methods. ESI mass spectra are obtained with triple quadrupole Micromass Quattro mass spectrometer. LDI and MALDI experiments are performed by Autoflex II mass spectrometer. Results. In the ESI experiments in the positive ion mode abundant peaks of protonated and cationized AP molecules as well as the peaks of AP clusters nAP•H+ and nAP•Na+ (n=2÷4) are revealed in the mass spectra. This result testifies to the formation of stable noncovalent complexes of the AP molecules in the polar media and confirms the AP ability of formation nanosomes for drug delivery. Analysis of LDI and MALDI mass spectra of AP in positive and negative ion modes shows that in the presence of molecular ions of AP, the peaks of AP dimers or larger AP clusters are not recorded. The ESI probing of the model system containing AP and dipalmitoylphosphatidylcholine (DPPC) reveals stable AP•DPPC•H+ complex which models the AP intermolecular interactions with the phospholipid components of biomembranes and/or liposomes under AP functioning as a drug delivery assisting agent. Conclusions. The current study demonstrates the applicability of all tested mass spectrometric techniques for AP identification in solutions and solid phase, while for the purpose of examining of the AP noncovalent complexes formation and study of AP interactions with biomolecules the ESI is defined as the most effective technique.

The photocatalytic conversion of lignin, obtained from camelina ( Camelina sativa ), over titania and iron titanate films has been studied with analysis of the products using laser desorptiopn/ionization and high-performance liquid chromatography. The photocatalytic reaction over titania films leads to the formation of the mixture of compounds, such as phenol, vanillic acid, resorcinol, and p -coumaryl alcohol. In the presence of iron titanate films, the predominant reaction products are vanillic acid and p -coumaryl. The highest antioxidant activity has been revealed in the case of lignin conversion products obtained over nitrogen-containing iron titanate films under visible light exposure.

The aim of this work was to synthesize cerium oxide nanoparticles (CeO2-NPs) using the Magnolia kobus leaves extract, to determine the composition of the extract and the participation of its components in the synthesis of NPs, to study the morphology and structure of the obtained NPs, to investigate their antibacterial activity. The composition of the plant extract and involving of its components in green synthesis of CeO2-NPs was studied by high-performance liquid chromatography (HPLC) and matrix-assisted laser/desorption ionization mass spectrometry (MALDI MS). It has been shown that the extract contained phenolic compounds (derivatives of simple phenols, flavonols, hydroxybenzoic and hydroxycinnamic acids, lignans, coumarins), as well as carotenoids, chlorophylls, terpenoids and sterols. The composition of the liquid phase from the reaction mixture (reaction liquid) after the NPs formation was studied to determine the components of the extract involved in the synthesis of CeO2-NPs. According to the results of HPLC and MALDI MS studies, significant differences were found in the composition of the plant extract and the reaction liquid: hydroxybenzoic acids, flavonoids and terpenoids disappeared or their concentration was significantly decreased, the content of lignans changed to a lesser extent, and it was observed the appearance of hydrophilic low-molecular compounds probably formed as a result of synthesis and stabilization of NPs. Synthesized CeO2-NPs were characterized by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). According to SEM and XRD, CeO2-NPs had a crystalline structure and were of spherical shape; the average size of the crystallites was ~ 20 nm, and the diameter of the primary particles was 50 ± 10 nm. It has been found that hydroxybenzoic acids, flavonoids and terpenoids are active participants in the green synthesis of CeO2-NPs in the presence of Magnolia kobus leaves extract, while lignans (fargesin/kobusin and eudesmin) are involved in less extend in the reduction/stabilization of CeO2-NPs. The synthesized particles possess antibacterial properties and can be used in the preparation of materials for medical and biological purposes.

Utilization of the second-most abundant biopolymer, lignin, in production of fine chemicals is considered as a strategy for environmental conservation and economic feasibility of technologies. Photocatalytic conversion of sodium lignosulfonate to low molecular weight compounds over eco-friendly semiconducting materials under simulated solar light is a perspective eco-innovative approach for “green technology” development. The more efficient depolymerization of lignosulfonate during photolytic reaction occurs at pH 2 as a result of sulfonic groups’ protonation, whereas the re-polymerization of hydrolyzed fragments to more complex structure in solutions at pH 5 and pH 9 is reported. Photo-sensibilization pathway toward polymer fragmentation is low effective process. It is shown that photocatalytic process is also more effective at pH 2 due to an electrostatic interaction of positively charge surface of metal oxides’ films and negatively charged NaLSA molecules. As shown by LDI MS investigation, the destruction of aromatic component of NaLSA molecule can be achieved in the presence of TiO2 film under simulated solar light due to the strong reductive power of superoxide radicals resulting in the benzoic ring-opening route. The mechanism of photocatalytic reaction over iron titanate films is governed by the presence of two semi-conductive crystalline phases, pseudobrookite and landauite, that are characterized by the anodically shifted energy positions of the conduction and valence bands compared to TiO2 providing an effective oxidation by HO• radicals. Nitrogen-doped iron titanate films are considered as a photocatalyst for the processes of low molecular weight aromatic compounds’ synthesis exhibiting activity under both simulated solar and visible light with the phenol yields of 0.96 μg mL−1 and 1.2 μg mL−1, respectively.

Досліджено склад і антиоксидантні властивості екстрактів, вилучених із рослин Deschampsia antarc tica É. Desv., зібраних у регіоні Аргентинських островів — півострова Київ (Морська Антарктика).. Склад екстрактів вивчено методами високоефективної рідинної хроматографії та мас-спектрометрії з матрично- активованою лазерною десорбцією/іонізацією; антиоксидантні властивості досліджено методом Фоліна— Чокальтеу та DPPH-тесту. Встановлено, що основними класами речовин, які містяться в екстрактах, є поліфенольні сполуки, зокрема флавоноїди, гідроксикоричні та гідроксибензойні кислоти. Підтверджено, що флавоноїди переважно представлені глікозидами лютеоліну; склад та кількість фенольних сполук залежить від генотипу рослини, місця походження та умов навколишнього середовища. Виявлено, що загальний вміст поліфенолів у досліджених екстрактах знаходиться в діапазоні 4, 33—10, 93 мг/г сирої сировини; найбільшу кількість активних речовин містять екстракти, вилучені з рослин острова Україна, а найменшу — з острова Дарбу. Результати антиоксидантних досліджень показали, що екстракти виявляють високу антирадикальну активність і здатні за 60 хв інгібувати понад 50 % DPPH радикалів. Одержані дані щодо складу поліфенолів у рослинах Deschampsia antarctica É. Desv. Можуть слугувати маркером для моніторингу кліматичних змін.

Fumed silica has found widespread application in industry due to variety of fascinating properties. Owing to its specific manufacturing process, it consists of finely dispersed particles and is featured with large specific surface area covered by profoundly reactive silanol groups which are available for chemical grafting. Spherical shape of fumed silica particles and lacking porosity provides a space-filling structure. These characteristics implement the fume silica’s utilization as high-surface-area carriers for various catalysts, i.e. metallic nanometer-sized particles, organic moieties, etc. Currently a great attention is called to on-surface grafting to improve the silica-based carrier. Most of research is carried out in area of liquid phase chemistry involving an abundance of expensive and often toxic solvents while the space-filling properties of silica are favoring reactions in fluidized bed conditions. In current research fumed silica (A-300) was a subject for hydridesilylation with triethoxysilane under fluidized bed conditions. In all synthesis reported in current research the insignificant amount of solvent (1.00 wt. % of the amount used in typical wet-chemical modifications method) was spent for the silica surface silylation. While the mass ratio of silica/TES was kept constant, other conditions, i.e. solvent/catalyst presence, surface pretreatment, additional treatment with water, and the fluidized bed heating mode have been varied. FTIR spectroscopy revealed the interaction between groups of triethoxysilane and silica surface silanol groups and demonstrated the effect of modification conditions on the density of the hydridesilyl groups coverage. The results of FTIR spectroscopic studies have confirmed the presence of grafted silicon hydride groups on the surface of modified silica, as well as the presence of ethoxy and/or silanol groups – either intact or formed due to hydrolysis of the ethoxy groups. Titrimetric and spectrophotometric analysis was performed to estimate the concentration of grafted SiH groups (in all samples prepared under fluidized bed conditions their concentration ranged within about 0.28–0.55 mmol/g as dependent on the reaction conditions). Other important aspects of fluidization such as the presence of solvent and/or hydrolyzing agent, bed heating mode and the effect of the silica sample thermal pre-treatment are also discussed.

З використанням двох різних процедур екстракції одержано вісім етанольних екстрактів із листя рослин Magnolia X soulangeana Soul.-Bod., Magnolia kobus та двох зразків Camellia japonica L. За допомогою високо- ефективної рідинної хроматографії, методу Фоліна—Чокальтеу і DPPH тесту вивчено склад та анти- оксидантні властивості одержаних екстрактів. Показано, що основними складовими екстрактів магнолій є глікозиди кверцетину та похідні оксикоричних кислот, тоді як у екстрактах камелій переважають катехі- ни і похідні оксибензойних кислот. Склад екстрактів залежить не тільки від виду рослини, а й від способу екстрагування; загалом, екстракти, одержані при температурі 60 °C та під дією ультразвуку, мають біль- ший вміст поліфенолів, ніж екстракти, отримані кип’ятінням рослинного матеріалу у 70 %-му етанолі при ~85 °C ; загальна кількість фенольних сполук у екстрактах змінювалась у діапазоні 50—150 мг/л. Виявлено, що, попри значну різницю у вмісті фенолів, всі екстракти мають дуже високу антиоксидантну актив- ність як у тесті Фоліна—Чокальтеу, так і в реакції з DPPH радикалами. Показано, що екстракти мають загальний фенольний індекс 1,5—7,5, а протягом 30 хв реакції сім з восьми екстрактів інгібують понад 50 % радикалів DPPH навіть після розведення у 10 разів. Екстракт камелії з найвищими антиоксидантними властивостями було протестовано як добавку до біодизелю, що має запобігти його окисненню під час збе- рігання. Стабільність біодизелю, одержаного з Camelina sativa (L.) Crantz, досліджували за прискореною процедурою при 43 °C протягом чотирьох тижнів, критерієм окиснення біопалива слугувало його кислотне число. Попередні результати показали, що екстракт камелії може бути ефективним антиоксидантним агентом — запобіжником окиснення біодизелю.

Fumed silica has found widespread application in industry due to variety of fascinating properties. Owing to its specific manufacturing process, it consists of finely dispersed particles and is featured with large specific surface area covered by profoundly reactive silanol groups which are available for chemical grafting. Spherical shape of fumed silica particles and lacking porosity provides a space-filling structure. These characteristics implement the fume silica’s utilization as high-surface-area carriers for various catalysts, i.e. metallic nanometer-sized particles, organic moieties, etc. Currently a great attention is called to on-surface grafting to improve the silica-based carrier. Most of research is carried out in area of liquid phase chemistry involving an abundance of expensive and often toxic solvents while the space-filling properties of silica are favoring reactions in fluidized bed conditions. In current research fumed silica (A-300) was a subject for hydridesilylation with triethoxysilane under fluidized bed conditions. In all synthesis reported in current research the insignificant amount of solvent (1.00 wt. % of the amount used in typical wet-chemical modifications method) was spent for the silica surface silylation. While the mass ratio of silica/TES was kept constant, other conditions, i.e. solvent/catalyst presence, surface pretreatment, additional treatment with water, and the fluidized bed heating mode have been varied. FTIR spectroscopy revealed the interaction between groups of triethoxysilane and silica surface silanol groups and demonstrated the effect of modification conditions on the density of the hydridesilyl groups coverage. The results of FTIR spectroscopic studies have confirmed the presence of grafted silicon hydride groups on the surface of modified silica, as well as the presence of ethoxy and/or silanol groups – either intact or formed due to hydrolysis of the ethoxy groups. Titrimetric and spectrophotometric analysis was performed to estimate the concentration of grafted SiH groups (in all samples prepared under fluidized bed conditions their concentration ranged within about 0.28–0.55 mmol/g as dependent on the reaction conditions). Other important aspects of fluidization such as the presence of solvent and/or hydrolyzing agent, bed heating mode and the effect of the silica sample thermal pre-treatment are also discussed.

Fumed silica (FS) is widely used in numerous fields of application, the plastics industry being one of the most significance, where FS has proved to be successful as an efficient thickening, thixotropic, and anti-settling agent, as well as reinforcing filler. Chemical modification of silica surface enlarges its functional capabilities. In particular, silica with grafted silicon hydride groups was found to be active in the processes of hydrosilylation of alkene and alkyne bonds in monomers during their polymerization, resulting in the formation of reinforced polymeric composites. Recently, specific epoxy resins have gained significance, and FS was found to be useful, particularly as rheological additive. The aim of this study was to evaluate the efficiency of hydride-silylated FS (HFS) as a potentially active reinforcing component for epoxy-based polymers. The activation energy for hydrosilylation of olefins is higher than that for ring-opening polymerization of epoxides, therefore, one may expect the latter process with participation of ≡SiH groups to proceed more readily. HFS was obtained via FS treatment with triethoxysilane. The presence of grafted silicon hydride groups was confirmed by means of IR spectroscopy, and their concentration measured by titrimetric and spectrophotometric analysis was found to be about 0.4 mmol/g. FS-epoxy and HFS-epoxy composites were prepared by the corresponding filler introduction (2 wt. % loading) into the mixture of epoxy monomer and amine hardener. The resulted materials after curing were subject to compression, bending, and adhesion tests. Compression tests revealed that filling with FS and HFS reduced the compressive strength by 10%, however, HFS-epoxy composite was found to possess an increased by 20 % Young’s modulus for compression as compared to that for the unfilled epoxy polymer. Upon this, 2 wt. % loading with silicas keeps the ductility of the polymer. Also, silica-containing epoxy polymers showed an improved bending strength and bending modulus, the former being two times higher for HFS-epoxy composite than that for the unfilled polymer. The adhesion to steel was found to increase by more than 2 times upon filling with silicas, HFS-epoxy composite being also superior as compared to the FS-epoxy one. Thus, preliminary results indicate that fumed silica with grafted silicon hydride groups shows promise as active reinforcing filler for epoxy polymers.

The structure of surface layer of octafluorocyclobutane radiofrequency plasma (c-C4F8 rf-plasma) treated fumed silica-pristine and chemically modified with triethoxy-, vinyltriethoxy-, or vinyltrichlorosilane-has been studied by means of FTIR- and X-ray photoelectron spectroscopy as well as temperature-programmed desorption mass spectrometry. The surface layer structure of the silylated nanosilicas after plasma fluorination was found to be defined by the reactivity of the pre-grafted groups. It was revealed that for hydride- and vinyl-silylated silicas at facile (about 15 min) treatment the single fragments with C:F ratio close to 1:1 are attached to surface (as in the case of pristine silica fluorination), whereas a long term (about 60 min) plasma treatment leads to formation of polymeric structures at the surface. Both the nature of pre-grafted groups, capable to be involved in polymerization reaction, and their concentration effect on these polymeric structures. Thus, at surface groups concentration of about 0.5 mmol/g fluorine-enriched polymeric chains are formed, while at twice as little concentration the chains with unsaturated bonds are generated.

Відомо, що пірогенний кремнезем є ефективним ентеросорбентом і носієм біологічно активних речовин, біодоступність яких може покращуватись у його присутності [1].Хімічне модифікування поверхні кремнезему розширює його функціональні можливості.Так, шляхом адсорбції водо-і жиророзчинного вітамінів С та Е на поверхні частково гідрофобізованого кремнезему було

Fumed silica (FS) is widely used in numerous fields of application, the plastics industry being one of the most significance, where FS has proved to be successful as an efficient thickening, thixotropic, and anti-settling agent, as well as reinforcing filler. Chemical modification of silica surface enlarges its functional capabilities. In particular, silica with grafted silicon hydride groups was found to be active in the processes of hydrosilylation of alkene and alkyne bonds in monomers during their polymerization, resulting in the formation of reinforced polymeric composites. Recently, specific epoxy resins have gained significance, and FS was found to be useful, particularly as rheological additive. The aim of this study was to evaluate the efficiency of hydride-silylated FS (HFS) as a potentially active reinforcing component for epoxy-based polymers. The activation energy for hydrosilylation of olefins is higher than that for ring-opening polymerization of epoxides, therefore, one may expect the latter process with participation of ≡SiH groups to proceed more readily. HFS was obtained via FS treatment with triethoxysilane. The presence of grafted silicon hydride groups was confirmed by means of IR spectroscopy, and their concentration measured by titrimetric and spectrophotometric analysis was found to be about 0.4 mmol/g. FS-epoxy and HFS-epoxy composites were prepared by the corresponding filler introduction (2 wt. % loading) into the mixture of epoxy monomer and amine hardener. The resulted materials after curing were subject to compression, bending, and adhesion tests. Compression tests revealed that filling with FS and HFS reduced the compressive strength by 10%, however, HFS-epoxy composite was found to possess an increased by 20 % Young’s modulus for compression as compared to that for the unfilled epoxy polymer. Upon this, 2 wt. % loading with silicas keeps the ductility of the polymer. Also, silica-containing epoxy polymers showed an improved bending strength and bending modulus, the former being two times higher for HFS-epoxy composite than that for the unfilled polymer. The adhesion to steel was found to increase by more than 2 times upon filling with silicas, HFS-epoxy composite being also superior as compared to the FS-epoxy one. Thus, preliminary results indicate that fumed silica with grafted silicon hydride groups shows promise as active reinforcing filler for epoxy polymers.

Recently, specific carbon-based nanomaterials (quantum dots, CDs) became highly attractive due to their low toxicity, good biocompatibility, chemical inertness, high photostability and fluorescence. Doping with some heteroatoms was found to be an effective approach to improve their luminescence. Besides, using the surface of silica as a support might facilitate the nanodots formation and expand the application area of carbon-silica composites. Recent advancements in synthesis of luminescent silica/CDs composites revealed great potential of such systems in bioimaging, sensor, as well as in solid-state lightning applications. Most of the synthetic methods are still relatively complex and costly. Here, the simple and inexpensive route to produce luminescent silica-based nanomaterials was used. The aim of this work was to study the luminescent properties of the materials obtained by pyrolysis of citric acid ureates at the nanosilica surface. Fumed silica was used as a support material. The salts with various ratios of citric acid and urea were obtained either in aqueous or alcohol solution, and they were further deposited on silica surface. The resulting material was then heat treated at the temperature of up to 270 °C, and the absorption and photoluminescence spectra for the samples obtained were collected and analyzed. The results have shown that irrespective of the solvent used, both dried and pyrolyzed samples possess the luminescent properties, with quantum yield of photoluminescence being within 7–11 %. The change of the citric acid-to-urea ratio in aqueous solution within 1:(1÷3) doesn’t affect the luminescent properties of dried samples, but further pyrolysis at 270 °C reduces the photoluminescence intensity. The solvent change to ethanol has an ambiguous influence on the luminescent properties of dried silica samples with different citric acid-to-urea ratio applied, however, further thermal treatment at 270 °C results in the formation of the materials with almost the same luminescence properties. Within the citric acid-to-urea ratios and the solvents used, as well as the heat treatment regimes applied, the variant with the 1:1 salt in the alcohol solution applied to the silica surface with further drying and heat treatment at 270 °C was found to be the most suitable.

Recently, specific carbon-based nanomaterials (quantum dots, CDs) became highly attractive due to their low toxicity, good biocompatibility, chemical inertness, high photostability and fluorescence. Doping with some heteroatoms was found to be an effective approach to improve their luminescence. Besides, using the surface of silica as a support might facilitate the nanodots formation and expand the application area of carbon-silica composites. Recent advancements in synthesis of luminescent silica/CDs composites revealed great potential of such systems in bioimaging, sensor, as well as in solid-state lightning applications. Most of the synthetic methods are still relatively complex and costly. Here, the simple and inexpensive route to produce luminescent silica-based nanomaterials was used. The aim of this work was to study the luminescent properties of the materials obtained by pyrolysis of citric acid ureates at the nanosilica surface. Fumed silica was used as a support material. The salts with various ratios of citric acid and urea were obtained either in aqueous or alcohol solution, and they were further deposited on silica surface. The resulting material was then heat treated at the temperature of up to 270 °C, and the absorption and photoluminescence spectra for the samples obtained were collected and analyzed. The results have shown that irrespective of the solvent used, both dried and pyrolyzed samples possess the luminescent properties, with quantum yield of photoluminescence being within 7–11 %. The change of the citric acid-to-urea ratio in aqueous solution within 1:(1?3) doesn’t affect the luminescent properties of dried samples, but further pyrolysis at 270 °C reduces the photoluminescence intensity. The solvent change to ethanol has an ambiguous influence on the luminescent properties of dried silica samples with different citric acid-to-urea ratio applied, however, further thermal treatment at 270 °C results in the formation of the materials with almost the same luminescence properties. Within the citric acid-to-urea ratios and the solvents used, as well as the heat treatment regimes applied, the variant with the 1:1 salt in the alcohol solution applied to the silica surface with further drying and heat treatment at 270 °C was found to be the most suitable.

The technique and the results of theoretical and experimental investigations of ion-optical properties and characteristics of mass spectrometers with magnetic focusing prisms have been described. The prospects of such devices for the ion beam analysis in mass spectrometry were shown.

Gelatin-based films with silica-to-gelatin weight ratio 1:5 or 8:5, containing either hydrophilic or hydrophilic-hydrophobic silica, have been prepared and studied by means of thermogravimetric analysis and temperature-programmed desorption mass spectrometry. It has been shown that silica presence has no effect on the mechanism of thermal decomposition of gelatin; however, it affects the kinetics of gelatin thermolysis both in vacuum and in air, including an increase in the activation energy of the volatile products formation at hydrophilic silica content about 17 wt. %. Hydrophobization of silica surface as well as an increase in hydrophilic silica concentration in the film from 17 to 62 wt. % decreases the activation energy of the volatile products formation during gelatin thermolysis. This effect is explained by reduced binding of gelatin with silica owing to either substitution of some surface silanol groups upon partial hydrophobization of silica, or their involving into interparticle rather than in silica-gelatin interactions at higher silica content.