Macedonian Journal of Chemistry and Chemical Engineering最新文献_第9页

Mandarin peel as an auspicious functional filler for polymer composites 桔皮作为高分子复合材料的吉祥功能填料

IF 1 4区化学

Macedonian Journal of Chemistry and Chemical Engineering Pub Date : 2021-05-11 DOI: 10.20450/MJCCE.2021.2236

A. Hejna, M. Barczewski, P. Kosmela, Joanna Aniśko, O. Mysiukiewicz, M. Marć

引用次数: 5

The influence of thermodynamic parameters on alkaline activator of geopolymers and structure of geopolymers 热力学参数对地质聚合物碱性活化剂及地质聚合物结构的影响

IF 1 4区化学

Macedonian Journal of Chemistry and Chemical Engineering Pub Date : 2021-05-11 DOI: 10.20450/MJCCE.2021.2127

M. Ivanović, S. Nenadović, V. Pavlović, Ivona R. Radović, M. Kijevčanin, V. Pavlović, Ljiljana M. Kljajević

引用次数: 5

Chromatographic parameters as tools for predicting the biological activity of azo derivatives 用色谱参数预测偶氮衍生物的生物活性

IF 1 4区化学

Macedonian Journal of Chemistry and Chemical Engineering Pub Date : 2021-05-11 DOI: 10.20450/MJCCE.2021.2045

S. Apostolov, G. Vastag

引用次数: 0

ICP-OES elemental impurities study on different pharmaceutical dosage forms of Ibuprofen using microwave-assisted digestion procedure 微波消解法研究不同剂型布洛芬的ICP-OES元素杂质

IF 1 4区化学

Macedonian Journal of Chemistry and Chemical Engineering Pub Date : 2021-05-11 DOI: 10.20450/MJCCE.2021.2100

Katerina Jancevska, G. Petrushevski, Mirjana Bogdanoska, T. Stafilov, S. Ugarkovic

{"title":"ICP-OES elemental impurities study on different pharmaceutical dosage forms of Ibuprofen using microwave-assisted digestion procedure","authors":"Katerina Jancevska, G. Petrushevski, Mirjana Bogdanoska, T. Stafilov, S. Ugarkovic","doi":"10.20450/MJCCE.2021.2100","DOIUrl":"https://doi.org/10.20450/MJCCE.2021.2100","url":null,"abstract":"Fast and simple closed-vessel microwave-assisted digestion procedure was developed for decomposition of three pharmaceutical dosage forms of ibuprofen such as tablets, suspension and gel, prior to elemental impurity analysis by one robust and precise ICP-OES method. Samples were digested by four-step microwave program consisting of a 10 min temperature gradient to 180°C, maintained at 180°C for 10 min, followed by 5 min ramping time to 210°C with holding time of 10 min on 210°C. Subsequently, ICP-OES method was developed and validated for simultaneous determination of selected elemental impurities. Results of recovery studies range between 77% and 105% for each element in all analyzed formulations. Correlation coefficients of the regression equations were higher than 0.999 for all analyzed elements. Validation results reveal that the proposed method is specific, accurate, and precise and could be applied for simultaneous quantitative analysis of multi element solutions in different pharmaceutical dosage forms of ibuprofen.","PeriodicalId":18088,"journal":{"name":"Macedonian Journal of Chemistry and Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49093276","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

Variability of the arbutin content in wild growing populations of Arctostaphylos uva-ursi (L.) Spreng from Korab Mountain, Western Balkan 西巴尔干Korab山熊果苷在野生种群中含量的变异性

IF 1 4区化学

Macedonian Journal of Chemistry and Chemical Engineering Pub Date : 2021-05-11 DOI: 10.20450/MJCCE.2021.2095

G. Stefkov, Ivana Cvetkovikj Karanfilova, Viktorija Labroska, Orhidea Krsteska, Bujar Qazimi, M. Karapandzova, Z. Gjoni, N. Bardhi, S. Kulevanova

{"title":"Variability of the arbutin content in wild growing populations of Arctostaphylos uva-ursi (L.) Spreng from Korab Mountain, Western Balkan","authors":"G. Stefkov, Ivana Cvetkovikj Karanfilova, Viktorija Labroska, Orhidea Krsteska, Bujar Qazimi, M. Karapandzova, Z. Gjoni, N. Bardhi, S. Kulevanova","doi":"10.20450/MJCCE.2021.2095","DOIUrl":"https://doi.org/10.20450/MJCCE.2021.2095","url":null,"abstract":"Due to the presence of arbutin and hydroquinone in the bearberry plant (Arctostaphylos uva-ursi (L.) Spreng., Ericaceae), it is widely used as a urinary tract antiseptic and diuretic. The herbal substance consists of whole or cut dried leaves, and it should not contain less than 7.00% of anhydrous arbutin (Ph.Eur.10). The supply of this herbal substance in Balkan countries mainly comes from a wild plant harvested in the mountains. It is a common practice to collect the leaves during the flowering season of the plant (June-July). There is an abundance of wild growing natural populations of bearberry on Korab Mountain that represents a unique natural resource of this herbal substance for both countries, Albania and North Macedonia. The aim of the present study was to determine the arbutin content and to assess its variability in the bearberry leaves of seven wild populations from Korab Mountain. The leaves were collected monthly (May-October) during a period of 3 years (2014-2016). The HPLC assay (Ph.Eur.10) revealed that all populations have arbutin content over 7.00% (7.03-9.42%) and that the highest content of arbutin can be attained in September/October, during the phase after the fructification. Statistical analysis showed that there is significant difference between the content of arbutin in the different populations. The content was related to the altitude of the collection site and the collection month and year.","PeriodicalId":18088,"journal":{"name":"Macedonian Journal of Chemistry and Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42685840","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

Procedure for the assessment of cognitive complexity: Development and implementation in the topic "Hydrolysis of salts" 认知复杂性评估程序：“盐的水解”专题的发展和实施

IF 1 4区化学

Macedonian Journal of Chemistry and Chemical Engineering Pub Date : 2021-05-11 DOI: 10.20450/MJCCE.2021.2240

Saša A. Horvat, J. Mihajlović, Tamara N. Rončević, Dušica D. Rodić

引用次数: 1

Synthesis and characterization of novel 1,2,3-triazole-bridged oxime polyurethanes obtained from an isomannide derivative 异曼尼衍生物制备新型1,2,3-三唑桥肟聚氨酯的合成与表征

IF 1 4区化学

Macedonian Journal of Chemistry and Chemical Engineering Pub Date : 2021-05-09 DOI: 10.20450/MJCCE.2021.2220

F. Bayrak, A. Oral, K. Ay

引用次数: 2

Critical aspects in exploring time analysis for the voltammetric estimation of kinetic parameters of surface electrode mechanisms coupled with chemical reactions 探索与化学反应耦合的表面电极机制动力学参数的伏安估计的时间分析的关键方面

IF 1 4区化学

Macedonian Journal of Chemistry and Chemical Engineering Pub Date : 2021-05-05 DOI: 10.20450/MJCCE.2021.2270

R. Gulaboski, V. Mirčeski, M. Lovrić

{"title":"Critical aspects in exploring time analysis for the voltammetric estimation of kinetic parameters of surface electrode mechanisms coupled with chemical reactions","authors":"R. Gulaboski, V. Mirčeski, M. Lovrić","doi":"10.20450/MJCCE.2021.2270","DOIUrl":"https://doi.org/10.20450/MJCCE.2021.2270","url":null,"abstract":"The accurate determination of the rate constant related to the electron transfer step of so-called “surface redox active compounds” by voltammetric measurements is very important because it is linked to the reactivity and stability of many biological and chemical systems such as redox enzymes, vitamins, hormones, and many more. Evaluation of the kinetics of the electron transfer is often challenging, especially when chemical equilibria are coupled to the electron transfer step. In this work, we theoretically consider some critical aspects of the time-related methodologies in square-wave voltammetry (SWV), which is designed to analyze the kinetics of the electron transfer step of surface mechanisms coupled with chemical reactions. We demonstrate with a series of simulated scenarios that caution must be taken when exploring the time-related analysis for kinetic characterizations for both surface CE and EC mechanisms. The main concern stems from the fact that the SW frequency simultaneously affects both the kinetics of electron transfer and that of chemical reactions as well. Under defined conditions, the SW frequency variation in the case of surface EC and CE mechanisms may produce unexpected features of the voltammetric patterns. In many scenarios, time-independent analysis, such as those related to the square-wave amplitude and potential increment, are seen as alternative tools to evaluate the rate parameter of electrode reactions.","PeriodicalId":18088,"journal":{"name":"Macedonian Journal of Chemistry and Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43273221","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

Infrared and Raman spectra of magnesium ammonium phosphate hexahydrate (struvite) and its isomorphous analogues. X. Vibrational spectra of magnesium rubidium arsenate hexahydrate and magnesium thallium arsenate hexahydrate 六水磷酸铵镁(鸟粪石)及其同形类似物的红外和拉曼光谱。十、六水合砷酸铷镁和六水合砷酸铊镁的振动谱

IF 1 4区化学

Macedonian Journal of Chemistry and Chemical Engineering Pub Date : 2020-12-11 DOI: 10.20450/mjcce.2020.2168

V. Stefov, V. Koleva, M. Najdoski, A. Cahil, Z. Abdija

{"title":"Infrared and Raman spectra of magnesium ammonium phosphate hexahydrate (struvite) and its isomorphous analogues. X. Vibrational spectra of magnesium rubidium arsenate hexahydrate and magnesium thallium arsenate hexahydrate","authors":"V. Stefov, V. Koleva, M. Najdoski, A. Cahil, Z. Abdija","doi":"10.20450/mjcce.2020.2168","DOIUrl":"https://doi.org/10.20450/mjcce.2020.2168","url":null,"abstract":"Polycrystalline samples of struvite-type MgRbAsO 4 ·6H 2 O and MgTlAsO 4 ·6H 2 O in both protiated and deuterated forms have been prepared for the first time by a precipitation method. Detailed analysis of their infrared (IR) and Raman (R) spectra recorded at room temperature (RT) and liquid nitrogen temperature (LNT) has been carried out and assignment of the vibrational bands has been proposed. The observed spectral pictures confirm the isostructurality of the two arsenate salts in agreement with the structural data. Similarly to other struvite-type and structure-related arsenate salts, the n 1 (AsO 4 ) modes appear at higher frequencies than the n 3 (AsO 4 ) vibrations. Low intensity and temperature sensitive bands that could be assigned as due to stretching Mg–O vibrations and n 4 (AsO 4 ) modes are observed below 500 cm –1 in the LNT IR spectra of the studied compounds, at 472 cm –1 and 445 cm –1 for the rubidium analogue and at 470 cm –1 and 440 cm –1 for the thallium analogue. In the far-infrared and Raman spectra many bands are observed between 400 cm –1 and 200 cm –1 , most of which are sensitive to deuteration, suggesting that they are not pure but coupled and can be related to n(Mg–Ow) modes. On the other hand, a band around 405 cm –1 in the spectra of the protiated compounds most probably is due to n 2 (AsO 4 ) mode because of its frequency position, intensity and slight sensitivity to deuteration.","PeriodicalId":18088,"journal":{"name":"Macedonian Journal of Chemistry and Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2020-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41949119","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

Probing students' higher order thinking skills using pictorial style questions 用图画式问题探究学生的高阶思维能力

IF 1 4区化学

Macedonian Journal of Chemistry and Chemical Engineering Pub Date : 2020-12-06 DOI: 10.20450/mjcce.2020.2133

Habiddin Habiddin, E. Page

引用次数: 5