IF 0.6 4区化学

Chemija Pub Date : 2020-04-21 DOI: 10.6001/chemija.v31i2.4221

V. Vickackaite, Gintarė Pipiraitė, Vilius Poškus, Ingrida Jurkutė, B. Bugelytė

引用次数: 3

Impedance of copper electrode in slightly acid Cu(II)-glycine solutions 铜电极在微酸Cu（II）-甘氨酸溶液中的阻抗

IF 0.6 4区化学

Chemija Pub Date : 2020-04-21 DOI: 10.6001/chemija.v31i2.4218

A. Survila, S. Kanapeckaitė, L. Gudavičiūtė, O. Girčienė

引用次数: 0

Sol–gel synthesis of calcium phosphate-based coatings – A review 溶胶-凝胶法合成磷酸钙基涂料的研究进展

IF 0.6 4区化学

Chemija Pub Date : 2020-02-26 DOI: 10.6001/chemija.v31i1.4169

K. Ishikawa, A. Kareiva

引用次数: 8

Surfactant-assisted microwave synthesis of carbon supported MnO2 nanocomposites and their application for electrochemical supercapacitors 表面活性剂辅助微波合成碳负载二氧化锰纳米复合材料及其在电化学超级电容器中的应用

IF 0.6 4区化学

Chemija Pub Date : 2020-02-26 DOI: 10.6001/chemija.v31i1.4168

J. Jablonskienė, D. Šimkūnaitė, J. Vaičiūnienė, A. Selskis, Audrius Drabavičius, V. Jasulaitienė, L. Tamašauskaitė-Tamašiūnaitė, E. Norkus

{"title":"Surfactant-assisted microwave synthesis of carbon supported MnO2 nanocomposites and their application for electrochemical supercapacitors","authors":"J. Jablonskienė, D. Šimkūnaitė, J. Vaičiūnienė, A. Selskis, Audrius Drabavičius, V. Jasulaitienė, L. Tamašauskaitė-Tamašiūnaitė, E. Norkus","doi":"10.6001/chemija.v31i1.4168","DOIUrl":"https://doi.org/10.6001/chemija.v31i1.4168","url":null,"abstract":"Center for Physical Sciences and Technology, 3 Saulėtekio Avenue, 10257 Vilnius, Lithuania MnO2/C nanocomposites have been prepared using a simple onestep microwave heating method by applying different concentrations of cationic surfactant – cetyl trimethylammonium bromide (CTAB). The morphology and composition of the prepared MnO2/C nanocomposites have been investigated using X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and inductively coupled plasma optical emission spectroscopy (ICP-OES). The electrochemical performance of the prepared nanocomposites has been analysed using cyclic voltammetry. It was found that a high specific capacitance (Cs) of 742 F g −1 at a scan rate of 10 mV s−1 in a 1 M Na2SO4 solution has been obtained for the MnO2/C nanocomposite that has the mass loading of 0.140 mg cm−2 and has been synthesized in the absence of CTAB. Meanwhile, the application of CTAB allowed the increase in the mass loading of MnO2 in the nanocomposites. In the presence of CTAB, the highest value of 654 F g−1 at a scan rate of 10 mV s−1 has been obtained for MnO2/C that has the mass loading of 0.570 mg cm−2. This result confirmed a good performance of the prepared MnO2/C nanocomposites as the electrode material for supercapacitors.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2020-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45635607","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}

引用次数: 0

Electroless deposition of nickel boron coatings using morpholine borane as a reducing agent 以morpholine硼烷为还原剂化学沉积镍硼涂层

IF 0.6 4区化学

Chemija Pub Date : 2020-02-26 DOI: 10.6001/chemija.v31i1.4167

Z. Sukackienė, K. Antanavičiūtė, J. Vaičiūnienė, L. Tamašauskaitė-Tamašiūnaitė, A. Naujokaitis, E. Norkus

引用次数: 5

Essential oil composition of Artemisia abrotanum L. during different vegetation stages in Lithuania 蒿属植物的精油成分。在立陶宛的不同植被阶段

IF 0.6 4区化学

Chemija Pub Date : 2020-02-26 DOI: 10.6001/chemija.v31i1.4171

S. Saunoriūtė, O. Ragažinskienė, L. Ivanauskas, M. Marksa

{"title":"Essential oil composition of Artemisia abrotanum L. during different vegetation stages in Lithuania","authors":"S. Saunoriūtė, O. Ragažinskienė, L. Ivanauskas, M. Marksa","doi":"10.6001/chemija.v31i1.4171","DOIUrl":"https://doi.org/10.6001/chemija.v31i1.4171","url":null,"abstract":"3 Department of Analytical and Toxicological Chemistry, Lithuanian University of Health Science, 13 Sukilėlių Street, 50162 Kaunas, Lithuania Artemisia abrotanum L. was introduced in the Middle of Lithuania Collection of Spice–Melliferous Plants of the Scientific Sector of Medicinal and Aromatic Plants of the Botanical Garden ex situ at Vytautas Magnus University since 1980. The object of investigation was Artemisiae abrotani herba of Artemisia abrotanum L. All samples were collected at different vegetation stages: growth and leaf production, flower bud development, the beginning of flowering, massive flowering and the end of flowering. Essential oils were obtained by hydrodistillation. The chemical composition of the essential oils of Artemisiae abrotani herba was studied by GC/MS in the Department of Analytical and Toxicological Chemistry at the Lithuanian University of Health Science in 2018–2019. Fifty-six compounds of the oil were identified, of which (+)-piperitone was the major component (20.38–38.48%). The data in this study showed a remarkable quantitative variation of constituents in the essential oils. The highest content and diversity of compounds was determined during the flower bud development stage. Sixty identified compounds in this stage reached 76.6% of the identified oil content. The highest concentration of this compound (38.48%) was detected at the end of the flowering vegetation stage and the lowest amount (20.38%) was found during the growth and leaf production. Among the other major compounds were (+)-piperitone, 1,4-cineole, lavandulyl butyrate, aromandendrene and isogermacrene D.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2020-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45266924","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}

引用次数: 3

Comparative study of equilibrium characteristics of Cu|Cu(II), Cu(I), glycine system containing sulfate or perchlorate as a supporting electrolyte 含硫酸盐和高氯酸盐的Cu|Cu（II）、Cu（I）、甘氨酸体系平衡特性的比较研究

IF 0.6 4区化学

Chemija Pub Date : 2019-12-04 DOI: 10.6001/chemija.v30i4.4098

Kazimieras Mikulskis, S. Kanapeckaitė, A. Survila

{"title":"Comparative study of equilibrium characteristics of Cu|Cu(II), Cu(I), glycine system containing sulfate or perchlorate as a supporting electrolyte","authors":"Kazimieras Mikulskis, S. Kanapeckaitė, A. Survila","doi":"10.6001/chemija.v30i4.4098","DOIUrl":"https://doi.org/10.6001/chemija.v30i4.4098","url":null,"abstract":"2 Center for Physical Sciences and Technology, 3 Saulėtekio Avenue, 10222 Vilnius, Lithuania The distribution of species in Cu(II)-glycine solutions, containing sulfate or perchlorate as a supporting electrolyte, is considered. Substantial differences are observed at pH < 4.5, where the molar fraction of monoligand complex (associate) CuSO4 reaches up to 20 percent of the total Cu(II) concentration. Cu(I)-containing species are generated at the Cu|solution interface. These are Cu+ aqua-complexes (acid media) or monoand bidentate Cu(I)-glycine complexes (alkaline media). The addition of sulfate reduces the content of Cu+ ions, but practically does not affect the distribution of Cu(I) complexes. The study of acidbase equilibria involving Cu+ ions shows that the thermodynamic probability of Cu2O formation remains low in both perchlorate and sulfate media. HSO4 – ions formed in acid media should be treated as rather labile proton donors. This is quantitatively confirmed by experimental data, according to which the rate of hydrogen evolution increases correspondingly when perchlorate is replaced by sulfate in glycine solutions.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":"30 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41794174","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}

引用次数: 3

Comparative investigation of oxidative degradation of organic dye in the presence of H2O2 and CuO nanoparticles synthesized by sol–gel method and green synthesis using flower (Matricaria chamomilla) extract 有机染料在H2O2和CuO存在下氧化降解的比较研究。溶胶-凝胶法制备纳米CuO与用洋甘菊提取物绿色合成

IF 0.6 4区化学

Chemija Pub Date : 2019-12-04 DOI: 10.6001/chemija.v30i4.4097

D. Kaušpėdienė, E. Zubrytė, A. Gefenienė, M. Jovaišaitė, V. Gefenas, R. Binkienė, R. Ragauskas, A. Selskienė, V. Pakštas

{"title":"Comparative investigation of oxidative degradation of organic dye in the presence of H2O2 and CuO nanoparticles synthesized by sol–gel method and green synthesis using flower (Matricaria chamomilla) extract","authors":"D. Kaušpėdienė, E. Zubrytė, A. Gefenienė, M. Jovaišaitė, V. Gefenas, R. Binkienė, R. Ragauskas, A. Selskienė, V. Pakštas","doi":"10.6001/chemija.v30i4.4097","DOIUrl":"https://doi.org/10.6001/chemija.v30i4.4097","url":null,"abstract":"2 Vytautas Magnus University, 58 K. Donelaičio Street, 44248 Kaunas, Lithuania In this study, CuO nanoparticles have been synthesized via a simple sol– gel method and green synthesis using flower (Matricaria chamomilla) extract. XRD analysis of the synthesized CuO nanoparticles clearly indicated a crystalline nature with a monoclinic structure regardless of the method of synthesis, while SEM revealed that the used synthesis methods affected the morphology of the CuO nanoparticles. The oxidative degradation kinetics of the organic dye Methyl Orange (MO) in the presence of the synthesized catalyst CuO and H2O2 has been investigated and compared depending on the dye concentration, reaction time and temperature. The catalytic activity of CuO was studied by measuring the UV–visible spectrum of the MO dye solution treated with CuO and H2O2. It was determined that the MO degradation reaction kinetics followed the pseudo-first-order mechanism. Thermodynamic studies indicated an endothermic nature (∆H# = +73.03 kJ mol–1) and a decrease in randomness at the catalyst CuO/solution interface during the reaction (∆S# = –0.021 kJ mol–1 K–1). At the same conditions, the green synthesized CuO nanoparticles exhibit similar activity properties as CuO synthesized using the sol–gel method. Besides, the green synthesis of CuO nanoparticles is simple and uses a small number of chemicals. The obtained CuO may be a promising catalyst for the oxidative degradation of organics, especially used in medical procedures.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45458200","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}

引用次数: 2

Study of deprotonation processes of polyaniline by differential multiwavelength Raman spectroscopy in an electrochemical system 电化学体系中聚苯胺去质子化过程的差分多波长拉曼光谱研究

IF 0.6 4区化学

Chemija Pub Date : 2019-12-04 DOI: 10.6001/chemija.v30i4.4099

R. Mažeikienė, G. Niaura, A. Malinauskas

引用次数: 1

Gas chromatographic determination of some carboxylic acids: comparison between solution and headspace analysis 气相色谱法测定某些羧酸:溶液法和顶空法的比较

IF 0.6 4区化学

Chemija Pub Date : 2019-12-04 DOI: 10.6001/chemija.v30i4.4100

B. Bugelytė, Karolina Ilonina, Vilius Poškus, V. Vickackaite

{"title":"Gas chromatographic determination of some carboxylic acids: comparison between solution and headspace analysis","authors":"B. Bugelytė, Karolina Ilonina, Vilius Poškus, V. Vickackaite","doi":"10.6001/chemija.v30i4.4100","DOIUrl":"https://doi.org/10.6001/chemija.v30i4.4100","url":null,"abstract":"Department of Analytical and Environmental Chemistry, Vilnius University, 24 Naugarduko Street, 03225 Vilnius, Lithuania Direct and headspace gas chromatographic analysis is compared for the determination of lactic, oxalic, succinic, malic and citric acids. For better chromatographic behaviour, prior to GC analysis carboxylic acids were derivatized using BSTFA as a silylation reagent. Three solvents – acetone, diethyl ether and dimethylformamide – were tested as a derivatization medium and DMF was considered as the best. Derivatization conditions were optimized and analytical characteristics of the direct gas chromatographic determination of analytes in solutions were determined. The method was applied for the determination of citric acid in food. For the analytes dissolved in DMF, the headspace gas chromatographic determination was not sensitive enough. Concentrations of the derivates in the headspace were very low, thus the limits of detection were high and the method was not of practical use. On the other hand, headspace gas chromatography can be applied for identifying of carboxylic acids in solid samples.","PeriodicalId":9720,"journal":{"name":"Chemija","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48770987","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}

引用次数: 2

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