Pub Date : 2021-05-29DOI: 10.6001/CHEMIJA.V32I2.4431
Linas Samardokas, R. Ivanauskas, S. Žalenkienė, A. Ivanauskas
Department of Physical and Inorganic Chemistry, Kaunas University of Technology, 19 Radvilėnų Street, 50254 Kaunas, Lithuania In this work, we investigated the formation of Tl-Se layers followed by doping with metal cations. A two-stage adsorption/diffusion process used to form Tl-Se layers involves (a) selenization in potassium selenotrithionate solution followed by (b) treatment with Tl+ precursor solutions. These layers have been successfully doped with Cu+/Cu2+, Ga3+ and Ag+ cations using a cation exchange reaction. The resulting chemical compositions of Tl-Se and Tl-M-Se (M = Cu, Ga, Ag) layers were investigated using the EDS and AAS methods. The bulk elemental composition and the Tl/Se molar ratio of the Tl-Se layers varied with the concentration of the Tl+ precursor solution, the exposure time in the Tl+ precursor solution, and the form of the Tl+ in the solution, whereas the EDS analysis showed that the surface was slightly enriched in thallium. The optical properties of the formed layers were studied. These layers were identified using room temperature reflection spectrum, the values of absorption edge, bandgap (Eg), band tail width (Urbach energy, EU) of the localised states, Steepness parameter (σ) and electron–phonon interaction (Ee-p).
立陶宛考纳斯理工大学物理与无机化学系，Radvilėnų Street 19, 50254 Kaunas, Lithuania在这项工作中，我们研究了金属阳离子掺杂后Tl-Se层的形成。用于形成Tl- se层的两阶段吸附/扩散过程包括(A)在硒代三硫酸钾溶液中硒化，然后(b)用Tl+前驱体溶液处理。利用阳离子交换反应，这些层成功地掺杂了Cu+/Cu2+、Ga3+和Ag+阳离子。用能谱仪和原子吸收光谱法研究了Tl-Se和Tl-M-Se (M = Cu, Ga, Ag)层的化学成分。Tl-Se层的体积元素组成和Tl/Se摩尔比随Tl+前驱体溶液浓度、在Tl+前驱体溶液中的暴露时间和溶液中Tl+的形态而变化，而能谱分析表明，表面的铊含量略有富集。研究了形成层的光学性质。利用室温反射谱、局域态的吸收边沿值、带隙(Eg)、带尾宽度(乌尔巴赫能，EU)、陡峭度参数(σ)和电子-声子相互作用(Ee-p)对这些层进行了识别。
{"title":"Influence of chemical composition and doping on optical properties of thallium selenide layers prepared by adsorption/diffusion method","authors":"Linas Samardokas, R. Ivanauskas, S. Žalenkienė, A. Ivanauskas","doi":"10.6001/CHEMIJA.V32I2.4431","DOIUrl":"https://doi.org/10.6001/CHEMIJA.V32I2.4431","url":null,"abstract":"Department of Physical and Inorganic Chemistry, Kaunas University of Technology, 19 Radvilėnų Street, 50254 Kaunas, Lithuania In this work, we investigated the formation of Tl-Se layers followed by doping with metal cations. A two-stage adsorption/diffusion process used to form Tl-Se layers involves (a) selenization in potassium selenotrithionate solution followed by (b) treatment with Tl+ precursor solutions. These layers have been successfully doped with Cu+/Cu2+, Ga3+ and Ag+ cations using a cation exchange reaction. The resulting chemical compositions of Tl-Se and Tl-M-Se (M = Cu, Ga, Ag) layers were investigated using the EDS and AAS methods. The bulk elemental composition and the Tl/Se molar ratio of the Tl-Se layers varied with the concentration of the Tl+ precursor solution, the exposure time in the Tl+ precursor solution, and the form of the Tl+ in the solution, whereas the EDS analysis showed that the surface was slightly enriched in thallium. The optical properties of the formed layers were studied. These layers were identified using room temperature reflection spectrum, the values of absorption edge, bandgap (Eg), band tail width (Urbach energy, EU) of the localised states, Steepness parameter (σ) and electron–phonon interaction (Ee-p).","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46044227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-29DOI: 10.6001/CHEMIJA.V32I2.4434
A. Laurikėnas, A. Kareiva
In this study, Y1-xLn3+x(BTC)(DMF)2(H2O) and Y0.8-xYb0.2Ln3+x(BTC)(DMF)2(H2O) metal organic frameworks (MOFs), which structure included lanthanide ions, Ln3+ (Er3+, Ho3+, Tm3+, Yb3+, Nd3+), suitable for monitoring the upconversion phenomenon, have been synthesised. For this purpose the precursor of the organic moiety, benzene-1,3,5-tricarboxylic acid (BTC), as one of the simplest and very frequently cited carboxylic acid analogues in MOF syntheses, has been selected. By characterising upconversion properties of new MOFs it was determined that only Er3+ can be used as an activator for one centre luminescence upconversion by a ground state absorption/ excited-state absorption (GSA/ESA) mechanism, while with Yb3+, Ho3+, Tm3+ and Nd3+ ions the upconversion was not observed. It was also established that BTC cannot initiate triplet–triplet annihilation upconversion (TTA-UC) as this mechanism sensitizer. Yb3+–Er3+ and Yb3+–Ho3+ ion pairs as a sensitizeractivator were suitable for two-centre luminescence upconversion by a GSA/ excited-state upconversion (GSA/ESU) mechanism. A pair of Yb3+–Tm3+, contrary as shown in the literature review, does not exhibit upconversion properties in the synthesised MOFs.
{"title":"Investigation of upconversion phenomenon in Y1-xLn3+x(BTC)(DMF)2(H2O) and Y0.8-xYb0.2Ln3+x(BTC)(DMF)2(H2O) metal organic frameworks","authors":"A. Laurikėnas, A. Kareiva","doi":"10.6001/CHEMIJA.V32I2.4434","DOIUrl":"https://doi.org/10.6001/CHEMIJA.V32I2.4434","url":null,"abstract":"In this study, Y1-xLn3+x(BTC)(DMF)2(H2O) and Y0.8-xYb0.2Ln3+x(BTC)(DMF)2(H2O) metal organic frameworks (MOFs), which structure included lanthanide ions, Ln3+ (Er3+, Ho3+, Tm3+, Yb3+, Nd3+), suitable for monitoring the upconversion phenomenon, have been synthesised. For this purpose the precursor of the organic moiety, benzene-1,3,5-tricarboxylic acid (BTC), as one of the simplest and very frequently cited carboxylic acid analogues in MOF syntheses, has been selected. By characterising upconversion properties of new MOFs it was determined that only Er3+ can be used as an activator for one centre luminescence upconversion by a ground state absorption/ excited-state absorption (GSA/ESA) mechanism, while with Yb3+, Ho3+, Tm3+ and Nd3+ ions the upconversion was not observed. It was also established that BTC cannot initiate triplet–triplet annihilation upconversion (TTA-UC) as this mechanism sensitizer. Yb3+–Er3+ and Yb3+–Ho3+ ion pairs as a sensitizeractivator were suitable for two-centre luminescence upconversion by a GSA/ excited-state upconversion (GSA/ESU) mechanism. A pair of Yb3+–Tm3+, contrary as shown in the literature review, does not exhibit upconversion properties in the synthesised MOFs.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":"32 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42361366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-29DOI: 10.6001/CHEMIJA.V32I2.4433
Yuliia Maslii, I. Bezruk, A. Materiienko, O. Ruban, L. Ivanauskas, Mariia Velia
4 Department of Analytical and Toxicological Chemistry, Lithuanian University of Health Sciences, 13 Sukilėliai Avenue, 50161 Kaunas, Lithuania A new high-performance liquid chromatography (HPLC) method for the simultaneous quantitative determination of active pharmaceutical substances and preservatives in a new dental medication has been developed. The optimization of HPLC method parameters was done through studies of a mobile phase composition and a detection wavelength. Our developing method uses an ACE C18 column (250 × 4.6 mm, 5 μm) and a gradient mode for separation with the acetonitrile and phosphate buffer solution (adjusted to pH 3.0) as mobile phases. The flow rate is 1 ml/ min, and the detection was set at 260 nm (DAD). The method was evaluated according to the ICH guidelines and the State Pharmacopoeia of Ukraine in terms of specificity, accuracy, linearity and precision (repeatability and intermediate precision). The limit of detection and the limit of quantification were also calculated. The developed method was put in place for the analysis of a combined dental gel to a quantitative determination of the APIs (choline salicylate, lidocaine hydrochloride) and preservatives (methylparaben, propylparaben).
{"title":"Development of the simultaneous analysis of choline salicylate, lidocaine hydrochloride and preservatives in a new dental gel by HPLC method","authors":"Yuliia Maslii, I. Bezruk, A. Materiienko, O. Ruban, L. Ivanauskas, Mariia Velia","doi":"10.6001/CHEMIJA.V32I2.4433","DOIUrl":"https://doi.org/10.6001/CHEMIJA.V32I2.4433","url":null,"abstract":"4 Department of Analytical and Toxicological Chemistry, Lithuanian University of Health Sciences, 13 Sukilėliai Avenue, 50161 Kaunas, Lithuania A new high-performance liquid chromatography (HPLC) method for the simultaneous quantitative determination of active pharmaceutical substances and preservatives in a new dental medication has been developed. The optimization of HPLC method parameters was done through studies of a mobile phase composition and a detection wavelength. Our developing method uses an ACE C18 column (250 × 4.6 mm, 5 μm) and a gradient mode for separation with the acetonitrile and phosphate buffer solution (adjusted to pH 3.0) as mobile phases. The flow rate is 1 ml/ min, and the detection was set at 260 nm (DAD). The method was evaluated according to the ICH guidelines and the State Pharmacopoeia of Ukraine in terms of specificity, accuracy, linearity and precision (repeatability and intermediate precision). The limit of detection and the limit of quantification were also calculated. The developed method was put in place for the analysis of a combined dental gel to a quantitative determination of the APIs (choline salicylate, lidocaine hydrochloride) and preservatives (methylparaben, propylparaben).","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47425093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-27DOI: 10.6001/CHEMIJA.V32I1.4395
Edita Sodaitienė, D. Kaušpėdienė, A. Gefenienė, V. Gefenas, R. Ragauskas, R. Ramanauskas
Center for Physical Sciences and Technology, 3 Saulėtekio Avenue, 10257 Vilnius, Lithuania Oxidative degradation of metal complex dye Sanodure Green (SG) in the presence of H2O2 and nanostructured catalyst CuO prepared from copper plating effluents has been investigated. The activity of the CuO catalyst in the oxidative degradation reaction depended on the SG concentration, reaction time and temperature. The reaction followed a pseudo-first order kinetic model, and the rate constant was highly dependent on the increase in temperature, but only slightly on the SG concentration. Thermodynamic studies have shown that the degradation reaction of SG is endothermic. The use of copper plating effluents for the preparation of nanostructured catalyst CuO makes it possible to avoid the accumulation of difficult-to-recycle copper oxide sludge formed during effluent neutralization, and to manage copper plating and aluminum dyeing effluents more economically.
{"title":"Utilization of copper plating effluents in the degradation of the dye Sanodure Green in the presence of H2O2","authors":"Edita Sodaitienė, D. Kaušpėdienė, A. Gefenienė, V. Gefenas, R. Ragauskas, R. Ramanauskas","doi":"10.6001/CHEMIJA.V32I1.4395","DOIUrl":"https://doi.org/10.6001/CHEMIJA.V32I1.4395","url":null,"abstract":"Center for Physical Sciences and Technology, 3 Saulėtekio Avenue, 10257 Vilnius, Lithuania Oxidative degradation of metal complex dye Sanodure Green (SG) in the presence of H2O2 and nanostructured catalyst CuO prepared from copper plating effluents has been investigated. The activity of the CuO catalyst in the oxidative degradation reaction depended on the SG concentration, reaction time and temperature. The reaction followed a pseudo-first order kinetic model, and the rate constant was highly dependent on the increase in temperature, but only slightly on the SG concentration. Thermodynamic studies have shown that the degradation reaction of SG is endothermic. The use of copper plating effluents for the preparation of nanostructured catalyst CuO makes it possible to avoid the accumulation of difficult-to-recycle copper oxide sludge formed during effluent neutralization, and to manage copper plating and aluminum dyeing effluents more economically.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49161817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-27DOI: 10.6001/CHEMIJA.V32I1.4397
Daiva Kazlauskienė, Giedre Kasparaviciene, Palma Nenortienė, M. Marksa, Julija Jukilaitytė, S. Velžienė, A. Ževžikovas
Studies of the composition of vegetable oils are expedient in order to achieve quality product modelling. The goal of this research was to determine the composition of fatty acids using gas chromatography (GC) and antioxidant activity using DPPH and ABTS spectrophotometric methods. Analysed oils were castor seed, sunflower seed, sesame seed, fibrous hemp seed, black radish seed and olive oils. Different classes of fatty acids were determined: polyunsaturated, monounsaturated and saturated; omega-3, omega-6 and omega-9 acids and individual constituents. The study results showed that the dominant acids in all oils were oleic and linoleic fatty acids. The best ratio of omega-6 to omega-3 acids was found in fibrous hemp seed oil – 3:1. All analysed vegetable oils demonstrated a high antioxidant activity.
{"title":"Determination of fatty acid composition and antioxidant activity in vegetable oils","authors":"Daiva Kazlauskienė, Giedre Kasparaviciene, Palma Nenortienė, M. Marksa, Julija Jukilaitytė, S. Velžienė, A. Ževžikovas","doi":"10.6001/CHEMIJA.V32I1.4397","DOIUrl":"https://doi.org/10.6001/CHEMIJA.V32I1.4397","url":null,"abstract":"Studies of the composition of vegetable oils are expedient in order to achieve quality product modelling. The goal of this research was to determine the composition of fatty acids using gas chromatography (GC) and antioxidant activity using DPPH and ABTS spectrophotometric methods. Analysed oils were castor seed, sunflower seed, sesame seed, fibrous hemp seed, black radish seed and olive oils. Different classes of fatty acids were determined: polyunsaturated, monounsaturated and saturated; omega-3, omega-6 and omega-9 acids and individual constituents. The study results showed that the dominant acids in all oils were oleic and linoleic fatty acids. The best ratio of omega-6 to omega-3 acids was found in fibrous hemp seed oil – 3:1. All analysed vegetable oils demonstrated a high antioxidant activity.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47106746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-27DOI: 10.6001/CHEMIJA.V32I1.4398
K. Netosova, O. Zavada, A. Materiienko, I. Zhuravel, Serhii Baiurka
4 Department of Clinical Biochemistry, Forensic Toxicology and Pharmacy, Kharkiv Medical Academy of Post-graduate Education, 58 Amosova Street, 61176 Kharkiv, Ukraine The article presents results of studies on the development of a quantification method for a substance 7-(4-fluorobenzyl)-3-thioxo-2,3-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-8(7H)-one using the method of nonaqueous potentiometric titration. Validation of the developed method has been carried out confirming the following characteristics: linearity, accuracy and precision that match the acceptance criteria for these measures.
{"title":"Quantitative determination of the new substance 7-(4-fluorobenzyl)-3-thioxo-2,3-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(7H)-one as a potential pharmaceutical agent","authors":"K. Netosova, O. Zavada, A. Materiienko, I. Zhuravel, Serhii Baiurka","doi":"10.6001/CHEMIJA.V32I1.4398","DOIUrl":"https://doi.org/10.6001/CHEMIJA.V32I1.4398","url":null,"abstract":"4 Department of Clinical Biochemistry, Forensic Toxicology and Pharmacy, Kharkiv Medical Academy of Post-graduate Education, 58 Amosova Street, 61176 Kharkiv, Ukraine The article presents results of studies on the development of a quantification method for a substance 7-(4-fluorobenzyl)-3-thioxo-2,3-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-8(7H)-one using the method of nonaqueous potentiometric titration. Validation of the developed method has been carried out confirming the following characteristics: linearity, accuracy and precision that match the acceptance criteria for these measures.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46670962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-27DOI: 10.6001/CHEMIJA.V32I1.4396
Robert A. Olins, P. Lesnicenoks, J. Kleperis, A. Knoks, I. Lukoševičs
2 Faculty of Material Science and Applied Chemistry, Riga Technical University, 14/24 Azenes Street, 1048 Riga, Latvia Graphene was discovered in the early 21st century, but has already proven itself in many applications – energy, medicine, electronics, food and sports, and more. Functionalization of nanostructured carbon materials with both non-metallic and metallic atoms is possible in various ways, imparting enhanced or new properties to the starting material, even catalytic activity. A method of electrochemical exfoliation was used to obtain the graphene sheets and simultaneously functionalize them with nitrogen. To ensure N-doping the process is done in a NaN3 electrolyte solution which provides less quantity of oxygen groups that tend to block defect sites on the graphene, compared with such solvents as NaNO2. Two graphite electrodes are inserted into the electrolyte and a pulse power of 0–10V is applied. The solution containing the obtained material is filtered through a 0.1 μm filter and dried. The material is characterized using SEM, XRD and XPS. In the XPS characterization graphene oxide is used as a reference material.
{"title":"Electrochemical exfoliation-streamline method for synthesis of nitrogen doped graphene","authors":"Robert A. Olins, P. Lesnicenoks, J. Kleperis, A. Knoks, I. Lukoševičs","doi":"10.6001/CHEMIJA.V32I1.4396","DOIUrl":"https://doi.org/10.6001/CHEMIJA.V32I1.4396","url":null,"abstract":"2 Faculty of Material Science and Applied Chemistry, Riga Technical University, 14/24 Azenes Street, 1048 Riga, Latvia Graphene was discovered in the early 21st century, but has already proven itself in many applications – energy, medicine, electronics, food and sports, and more. Functionalization of nanostructured carbon materials with both non-metallic and metallic atoms is possible in various ways, imparting enhanced or new properties to the starting material, even catalytic activity. A method of electrochemical exfoliation was used to obtain the graphene sheets and simultaneously functionalize them with nitrogen. To ensure N-doping the process is done in a NaN3 electrolyte solution which provides less quantity of oxygen groups that tend to block defect sites on the graphene, compared with such solvents as NaNO2. Two graphite electrodes are inserted into the electrolyte and a pulse power of 0–10V is applied. The solution containing the obtained material is filtered through a 0.1 μm filter and dried. The material is characterized using SEM, XRD and XPS. In the XPS characterization graphene oxide is used as a reference material.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44578316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-19DOI: 10.6001/chemija.v31i4.4316
T. Charkova, Agnė Zdaniauskienė
Department of Organic Chemistry, Center for Physical Sciences and Technology, 3 Saulėtekio Avenue, 10257 Vilnius, Lithuania The synthesized gold nanoparticles (50–60 nm) were coated with thin (1.5–8 nm) layers of silicon, manganese and titanium dioxides. The obtained three species of nanospheres were applied for the analysis of self-assembled monolayer of thiophenol by shell-isolated nanoparticleenhanced Raman spectroscopy method. Detailed synthesis and comparison of the particle properties are provided in this report.
{"title":"Synthesis and comparison of gold nanoparticles coated with silicon, manganese and titanium dioxides","authors":"T. Charkova, Agnė Zdaniauskienė","doi":"10.6001/chemija.v31i4.4316","DOIUrl":"https://doi.org/10.6001/chemija.v31i4.4316","url":null,"abstract":"Department of Organic Chemistry, Center for Physical Sciences and Technology, 3 Saulėtekio Avenue, 10257 Vilnius, Lithuania The synthesized gold nanoparticles (50–60 nm) were coated with thin (1.5–8 nm) layers of silicon, manganese and titanium dioxides. The obtained three species of nanospheres were applied for the analysis of self-assembled monolayer of thiophenol by shell-isolated nanoparticleenhanced Raman spectroscopy method. Detailed synthesis and comparison of the particle properties are provided in this report.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2020-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42876352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-19DOI: 10.6001/chemija.v31i4.4325
S. Saunoriūtė, O. Ragažinskienė, L. Ivanauskas, M. Marksa, E. Šeinauskienė
3 Department of Analytical and Toxicological Chemistry, Faculty of Pharmacy, Lithuanian University of Health Science, 13 Sukilėlių Street, 50162 Kaunas, Lithuania In order to increase the diversity of medicinal plants and biologically active compounds accumulated in them, considerable attention is given to introduction of Artemisia L. genus plants in Lithuania. The aim of our study was to determinate the qualitative and quantitative composition of essential oils of Artemisia pontica L. introduced in Lithuania. The object of investigation – Artemisiae pontici herba were prepared in the Scientific Sector of Medicinal and Aromatic Plants, Scientific Department of Botanical Garden at Vytautas Magnus University in 2018–2019. Essential oils were separated by hydrodistillation method, their composition was analysed by gas chromatography/mass spectrometry methods in the Faculty of Pharmacy at Lithuanian University of Health Sciences in 2018–2020. The obtained results showed that a statistically significant (p > 0.05) higher amount and diversity of compounds from Artemisiae pontici herba essential oils were assessed in 2018 when HTC = 1.32. A strong correlation (r = 0.740) was assessed between the average of active temperatures and precipitation in 2019. The content of compounds was by 33.3% lower when HTC = 0.91. The other major compounds were 1,8-cineole (46.86%), 1,4-cineole (37.92%) and camphor (29.41–33.02%).
{"title":"The influence of meteorological factors on phytochemical composition of Artemisia pontica L.","authors":"S. Saunoriūtė, O. Ragažinskienė, L. Ivanauskas, M. Marksa, E. Šeinauskienė","doi":"10.6001/chemija.v31i4.4325","DOIUrl":"https://doi.org/10.6001/chemija.v31i4.4325","url":null,"abstract":"3 Department of Analytical and Toxicological Chemistry, Faculty of Pharmacy, Lithuanian University of Health Science, 13 Sukilėlių Street, 50162 Kaunas, Lithuania In order to increase the diversity of medicinal plants and biologically active compounds accumulated in them, considerable attention is given to introduction of Artemisia L. genus plants in Lithuania. The aim of our study was to determinate the qualitative and quantitative composition of essential oils of Artemisia pontica L. introduced in Lithuania. The object of investigation – Artemisiae pontici herba were prepared in the Scientific Sector of Medicinal and Aromatic Plants, Scientific Department of Botanical Garden at Vytautas Magnus University in 2018–2019. Essential oils were separated by hydrodistillation method, their composition was analysed by gas chromatography/mass spectrometry methods in the Faculty of Pharmacy at Lithuanian University of Health Sciences in 2018–2020. The obtained results showed that a statistically significant (p > 0.05) higher amount and diversity of compounds from Artemisiae pontici herba essential oils were assessed in 2018 when HTC = 1.32. A strong correlation (r = 0.740) was assessed between the average of active temperatures and precipitation in 2019. The content of compounds was by 33.3% lower when HTC = 0.91. The other major compounds were 1,8-cineole (46.86%), 1,4-cineole (37.92%) and camphor (29.41–33.02%).","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2020-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42855545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-19DOI: 10.6001/chemija.v31i4.4318
A. Zabielaitė, D. Šimkūnaitė, A. Balčiūnaitė, B. Šimkūnaitė-Stanynienė, I. Stalnionienė, L. Naruškevičius, Daina Upskuvienė, A. Selskis, L. Tamašauskaitė-Tamašiūnaitė, E. Norkus
State Research Institute Center for Physical Sciences and Technology, 3 Saulėtekio Avenue, 10257 Vilnius, Lithuania The electrochemical stability and durability of ZnCo alloy thin layers deposited on the titanium surface (denoted as ZnCo/Ti) and those modified by small amounts of Au nanoparticles (denoted as AuZnCo/Ti) prepared via the electrochemical metal deposition technique and a simple galvanic displacement have been investigated in alkaline sodium borohydride (NaBH4) solutions. The physical properties of the fabricated AuZnCo/Ti catalysts have been examined using field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX) and inductively coupled plasma optical emission spectroscopy (ICP-OES). The electrocatalytic activity of the ZnCo/Ti and AuZnCo/Ti catalysts toward the oxidation of NaBH4 has been evaluated in an alkaline medium using cyclic voltammetry (CV) and chronoamperometry (CA), whereas the catalytic efficiency of the catalysts for the hydrolysis reaction of NaBH4 has been also examined by measuring the amount of generated hydrogen via the classic water-displacement method. It has been determined that the modification of the ZnCo alloy coating by Au nanoparticles apparently improves not only the morphology and structure of the catalyst, but also the activity and stability of the one for the oxidation of NaBH4 in an alkaline medium as compared to those of ZnCo/Ti and bare Au. The AuZnCo/Ti catalysts that have Au loadings of 63 and 306 μg cm–2 give ca. 12 and 11, respectively, times higher NaBH4 oxidation current densities as compared to those of the bare Au catalyst. Moreover, the AuZnCo/Ti catalysts catalyze the hydrolysis reaction of NaBH4 in alkaline solutions.
{"title":"Investigation of stability of gold nanoparticles modified zinc–cobalt coating in an alkaline sodium borohydride solution","authors":"A. Zabielaitė, D. Šimkūnaitė, A. Balčiūnaitė, B. Šimkūnaitė-Stanynienė, I. Stalnionienė, L. Naruškevičius, Daina Upskuvienė, A. Selskis, L. Tamašauskaitė-Tamašiūnaitė, E. Norkus","doi":"10.6001/chemija.v31i4.4318","DOIUrl":"https://doi.org/10.6001/chemija.v31i4.4318","url":null,"abstract":"State Research Institute Center for Physical Sciences and Technology, 3 Saulėtekio Avenue, 10257 Vilnius, Lithuania The electrochemical stability and durability of ZnCo alloy thin layers deposited on the titanium surface (denoted as ZnCo/Ti) and those modified by small amounts of Au nanoparticles (denoted as AuZnCo/Ti) prepared via the electrochemical metal deposition technique and a simple galvanic displacement have been investigated in alkaline sodium borohydride (NaBH4) solutions. The physical properties of the fabricated AuZnCo/Ti catalysts have been examined using field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX) and inductively coupled plasma optical emission spectroscopy (ICP-OES). The electrocatalytic activity of the ZnCo/Ti and AuZnCo/Ti catalysts toward the oxidation of NaBH4 has been evaluated in an alkaline medium using cyclic voltammetry (CV) and chronoamperometry (CA), whereas the catalytic efficiency of the catalysts for the hydrolysis reaction of NaBH4 has been also examined by measuring the amount of generated hydrogen via the classic water-displacement method. It has been determined that the modification of the ZnCo alloy coating by Au nanoparticles apparently improves not only the morphology and structure of the catalyst, but also the activity and stability of the one for the oxidation of NaBH4 in an alkaline medium as compared to those of ZnCo/Ti and bare Au. The AuZnCo/Ti catalysts that have Au loadings of 63 and 306 μg cm–2 give ca. 12 and 11, respectively, times higher NaBH4 oxidation current densities as compared to those of the bare Au catalyst. Moreover, the AuZnCo/Ti catalysts catalyze the hydrolysis reaction of NaBH4 in alkaline solutions.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2020-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45864093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：