Visnik Kharkivs''kogo natsional''nogo universitetu Seriia ximiia最新文献

{"title":"Nitroxyl spin probe in ionic micelles: A molecular dynamics study","authors":"V. Farafonov, A. Lebed","doi":"10.26565/2220-637X-2020-34-02","DOIUrl":"https://doi.org/10.26565/2220-637X-2020-34-02","url":null,"abstract":"The compounds containing nitroxyl radical (NO˙) are actively used as spin probes to examine colloid systems, including lipid membranes and micelles. Their electron paramagnetic resonance spectrum provides information about the composition of the medium, in particular, the content of water there. Yet, the proper treatment of the measurement results demands understanding the microscopic characteristics of the molecular probe. In the present paper, we extend our previous studies on the microscopic state of acid-base and solvatochromic probes in surfactant micelles to the field of spin probes. We report the results of molecular dynamics simulation of a common spin probe, methyl-5-doxylstearate, in micelles of anionic (sodium n-dodecyl sulfate, SDS) and cationic (n-dodecyltrimethylammonium bromide, DTAB) surfactants. The localization of the molecule within the micelles, its shape, composition of the local environment, hydration were quantified and compared with the available relevant experimental data. No significant dissimilarity was found in the characteristics of the probe molecule in both kinds of micelles. However, the characteristics of the O˙ atom carrying the unpaired electron are pronouncedly different, namely, in DTAB micelles it is less hydrated and forms less hydrogen bonds with water. Similar situation was observed for the COO group. The main reason was found to be the interactions with cationic surfactant headgroups, which screen the O˙ atom and COO group from water. These findings allowed revisit the point of view that the surface layer of DTAB micelles as a whole is less hydrated in comparison to that of the SDS ones.","PeriodicalId":34181,"journal":{"name":"Visnik Kharkivs''kogo natsional''nogo universitetu Seriia ximiia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48775386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Atomic absorption and atomic emission with inductive connected plasma detection of Lead and Iron in strata water using new medias and standard composition samples","authors":"","doi":"10.26565/2220-637x-2020-34-05","DOIUrl":"https://doi.org/10.26565/2220-637x-2020-34-05","url":null,"abstract":"An influence of SAS (Тriton Х-100) concentration and ultrasound treatment time on the value of analytical signal at atomic absorption and atomic emission with inductive connected plasma detection of analytes in strata water was studied. Maximal analytical signal at of Lead and Iron was reached at using nonionogenic SAS which let us to decrease surface tension of the analyzed solution and to increase absorptivity at analytes detection. It was shown that using of the modern sample preparation increase sensibility of atomic absorption detection of Lead in 1,5 times and Iron in 1,8 times. By the methods of atomic absorption and atomic emission with inductive connected plasma spectroscopy and using acetylacetonates of Lead and Iron as standard composition samples, that let us to increase sensitivity of the detection of analytes, contain of Lead and Iron in strata water was determined. By variation of the sample volume and by \"injected-found out\" method we have proved that systematic error is not significant. The results, obtained by two independent methods were compared according to F- and t-criteria. It was proved that dispersions are homogenous and run of the means is not sufficient and proved by random scatter. By atomic absorption method we estimated the detection limit of the analytes according to the developed methodic and show that the obtained results are lower than the same data from literature. The developed methodic, according to its metrological characteristics, is competitive at international level.","PeriodicalId":34181,"journal":{"name":"Visnik Kharkivs''kogo natsional''nogo universitetu Seriia ximiia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69002003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design, rheology and microstructure of food-grade emulsion-based systems for delivery of vitamin D","authors":"","doi":"10.26565/2220-637x-2020-35-02","DOIUrl":"https://doi.org/10.26565/2220-637x-2020-35-02","url":null,"abstract":"The fortification of food with vitamin D has several limitations because this group of fat-soluble compounds may degrade or undergo undesirable changes during technologic processing and storage of food. The purpose of this study was to investigate emulsions for vitamin D3 delivery in commercial foods. Oil-in-water (o/w) emulsions stabilized by mixture of various proteins (whey protein isolate (WPI), skimmed milk powder (SMP) and vegan protein isolate (VPI)) as emulsifiers and carboxymethylcellulose as thickening agent were used. The shear stress and effective dynamic viscosity of the emulsions in the wide range of shear rates were experimentally determined. By approximating experimental flow curves using the power-law model, the values of the consistency coefficient and flow behavior index were obtained, which made it possible to classify the emulsions as systems with pseudoplastic flow. Within the framework of the structural approach, the rheological data were analyzed on the basis of the generalized rheological model of Casson. The contributions to the process of viscous flow calculated from the experimental data from the integral characteristics of associates of droplets and individual particles during their hydrodynamic interaction made it possible to explain the effect of changing the viscosity of emulsions from the nature of the emulsifier used. The zeta potential values determined by the dynamic light scattering method indicate the existence of a strong repulsive force as a factor for the stability of emulsions. The sign of the potential and its magnitude indicate the process of adsorption on the surface of fat droplets molecule of protein. The presence of a peak of flocculated particles in the histograms of the particle size distribution is explained by the presence of non-adsorbing polysaccharides, which are capable of the generation of aggregated emulsion structures through depletion flocculation. Regardless of the choice of the type and nature of the protein emulsifier - animal or plant origin, all studied systems were stable and can be considered for use as emulsion-based delivery systems of vitamin D. From an economic point of view, it is advisable to use dry milk as an emulsifier. The resulting emulsions can be used as a basis for the production of vitamin D3-fortified foods, in particular for dairy products.","PeriodicalId":34181,"journal":{"name":"Visnik Kharkivs''kogo natsional''nogo universitetu Seriia ximiia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69001706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In memoriam: Professor V.A. Starodub (5.01.1949 – 12.11.2020)","authors":"","doi":"10.26565/2220-637x-2020-34-07","DOIUrl":"https://doi.org/10.26565/2220-637x-2020-34-07","url":null,"abstract":"","PeriodicalId":34181,"journal":{"name":"Visnik Kharkivs''kogo natsional''nogo universitetu Seriia ximiia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69002086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesis of 1-(methylsulfonyl)-1-propene and N,N-dimethyl-1-propene-1-sulfonamide","authors":"","doi":"10.26565/2220-637x-2020-35-04","DOIUrl":"https://doi.org/10.26565/2220-637x-2020-35-04","url":null,"abstract":"Various vinylsulfones and vinylsulfonamides have a wide range of biological activities (mainly, inhibition of different types of enzymes) and are frequently used in synthetic organic chemistry (as active dienophiles, Michael acceptors and, generally, active agents in 1,4‑addition and electrocyclization reactions). However, despite numerous synthesized substances of this type, the synthetic protocols for the obtaining of the low molecular weight representatives of these compounds – 1‑(methylsulfonyl)-1-propene and N,N‑dimethyl-1‑propene-1-sulfonamide – seem to be still little known. In the present work we report a simple, efficient and general protocol for the dehydrative synthesis of 1‑(methylsulfonyl)-1‑propene and N,N‑dimethyl-1‑propene-1‑sulfonamide starting from corresponding 1-(methylsulfonyl)-2-propanol and N,N‑dimethyl-2‑hydroxypropanesulfonamide, respectively, using MeSO2Cl/organic base system basing on the preliminary experiment of 2‑(4‑bromophenyl)-N,N‑dimethylethenesulfonamide synthesis from 2‑(4‑bromophenyl)-2‑hydroxy-N,N-dimethylethanesulfonamide. The latter in its turn has been obtained starting from N,N‑dimethylmethanesulfonamide by lithiation with n-BuLi, subsequent action of 4‑bromobenzaldehyde and further workup. The applied protocol of vinyl derivatives synthesis allows to avoid isolation of intermediate mesyl derivatives, consisting of one-pot formation of leaving group and its elimination. Accordingly to coupling constants in 1H NMR spectra, synthesized N,N‑dimethyl-1-propene-1‑sulfonamide exists as mixture of E- and Z-isomers (in the ratio 88:12), while isolated 1‑(methylsulfonyl)-1‑propene and 2-(4-bromophenyl)-N,N‑dimethylethenesulfonamide are the most stable E‑isomers. The structures of the synthesized compounds are confirmed by the methods of 1H NMR-spectroscopy and mass-spectrometry.","PeriodicalId":34181,"journal":{"name":"Visnik Kharkivs''kogo natsional''nogo universitetu Seriia ximiia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69002591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Visual binary testing of methanol contained in ethyl alcohol","authors":"","doi":"10.26565/2220-637x-2020-35-05","DOIUrl":"https://doi.org/10.26565/2220-637x-2020-35-05","url":null,"abstract":"A method for control of methanol traces in rectified ethyl alcohol and alcoholic drinks based on visual binary testing using one reference sample was proposed. An indicator reaction of formaldehyde interaction (product of methanol oxidation) with chromotropic acid disodium salt was chosen for methanol screening. The conditions of indicator reaction proceeding are analogous as for the spectrophotometric technique of methanol determination: methanol was oxidized to formaldehyde with potassium permanganate in an acidic medium; the formaldehyde then reacts with chromotropic acid in the presence of hot concentrated sulfuric acid and forms a violet product (color of this product is stable for 12 hours). It was established that the absorption spectrum of the reaction product does not change on going from 96% ethanol to aqueous-ethanol solutions with a volume fraction of 40% ethanol. The maximum light absorption of the reaction product corresponded to 570 nm. All further studies were carried out in water-ethanol solutions with a volume fraction of ethanol of 40%. According to regulatory documents the normalized limiting content of methanol (clim) in ethyl alcohol of the “Lux” grade (the most common in the alcoholic industry) and alcoholic beverages is 0.01% by by volume counted upon anhydrous alcohol. The comparison sample (the solution of colored reaction product of indicator reaction) had to be less than the normilized level on the value which providing the risk of false-negative test result not more than 5%. To determination the threshold concentration of methanol in the comparison sample was applied the statistics of observation. For the aim the solution of colored product corresponding to the normalized limiting methanol concentration clim = 0.01% by volume was prepared and comparison samples with lower methanol concentrations were also prepared. The interval of unreliability was discovered with the help of observers. The frequency of detecting of the difference in the color of comparison samples and normalized sample (P(c)) changed from 0 to 1 in this interval. The value of methanol concentration 0.0072% by volume counted upon anhydrous alcohol was taken for the lower boundary of the interval and the value of methanol concentration 0.01% by volume counted upon anhydrous alcohol was chosen the upper border of the interval. This interval was divided on eight concentrations with step Dс = 0.0004% by volume. Three parallel series of solutions were prepared and 48 observations for each concentration were received. The experimental efficiency curve obtained was checked for compliance with the mathematical functions of the known distributions: normal, logistic, lognormal, exponential and Weibull distribution function using the statistical criterions c2 and Kolmogorov-Smirnov λ. The efficiency curve was described by the theoretical functions of the lognormal and Weibull distributions. Calculated at a confidence level of 0.95 estimation of the threshold ","PeriodicalId":34181,"journal":{"name":"Visnik Kharkivs''kogo natsional''nogo universitetu Seriia ximiia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69002639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In memoriam: Associate Professor S.A. Komykhov (9.09.1971 – 22.10.2020)","authors":"","doi":"10.26565/2220-637x-2020-34-09","DOIUrl":"https://doi.org/10.26565/2220-637x-2020-34-09","url":null,"abstract":"","PeriodicalId":34181,"journal":{"name":"Visnik Kharkivs''kogo natsional''nogo universitetu Seriia ximiia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69002143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to «Recent advances in theoretical investigation of titanium dioxide nanomaterials. A review»","authors":"","doi":"10.26565/2220-637x-2020-34-06","DOIUrl":"https://doi.org/10.26565/2220-637x-2020-34-06","url":null,"abstract":"","PeriodicalId":34181,"journal":{"name":"Visnik Kharkivs''kogo natsional''nogo universitetu Seriia ximiia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69002021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In memoriam: Associate Professor A.V. Kravchenko (20.12.1955 - 9.03.2020)","authors":"","doi":"10.26565/2220-637x-2020-34-08","DOIUrl":"https://doi.org/10.26565/2220-637x-2020-34-08","url":null,"abstract":"","PeriodicalId":34181,"journal":{"name":"Visnik Kharkivs''kogo natsional''nogo universitetu Seriia ximiia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69002098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sorption properties of polymeric beads and films containing tetraoctyl diglycolamide towards europium (III) ions","authors":"","doi":"10.26565/2220-637x-2020-35-01","DOIUrl":"https://doi.org/10.26565/2220-637x-2020-35-01","url":null,"abstract":"The article presents results obtained during investigation of Eu(III) ion removal from aqueous solutions using triacetate cellulose films and styrene-divinylbenzene copolymer beads containing tetraoctyl diglycolamide (TODGA). A simple method for manufacturing films containing up to 50 % w/w TODGA is provided. Solution acidity effect on the removal rate of Eu(III) ions was studied. Maximum removal of Eu(III) ions was obtained in nitric acid solutions with concentrations of 1-6 mol/l. Additionally, increase in the europium removal rate is also observed at pH > 2 for beads and in the pH range of 2 to 4 for films. In the former case increase in the removal rate is explained by increase in the nitrate ion concentration in the solution and Eu(NO3)3(TODGA)3 complex formation, and in the latter case – by decrease in TODGA protonation rate with рН growth. Observed trends indicate a high similarity in surface sorption mechanisms between the materials studied. Sorption equilibrium of Eu(III) ions onto the styrene-divinylbenzene copolymer beads impregnated with TODGA is adequately fitted to Langmuir sorption isotherm. The maximum sorption capacity of this material for Eu(III) removal from solutions with nitric acid concentration of 1 mol/l is 7.4 mg/g. It has been found that the maximum removal rate of Eu(III) ions by the triacetate cellulose films is achieved for TODGA content in the films ≥ 40 % w/w. The possibility of selective europium sorption from natural water using both beads and films is shown. Although cations present in natural water do not bind to sorbents studied, there is still slight deterioration in sorption properties when moving from model solutions to natural water. Complete desorption of Eu(III) ions from the film surface is achieved by washing three times with an EDTA solution, рН = 6.8. Prepared films can be reused for Eu(III) ion removal.","PeriodicalId":34181,"journal":{"name":"Visnik Kharkivs''kogo natsional''nogo universitetu Seriia ximiia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69002163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}