Pub Date : 2020-11-17DOI: 10.20450/MJCCE.2020.2060
N. Lisov, A. Petrovic, U. Čakar, M. Jadranin, V. Tešević, Ljiljana Bukarica-Gojković
In this study, we estimated the usage of Cabernet Sauvignon in microvinifications, obtaining wines with increased phenolic compound content. Kinetic extraction of phenolic compounds during alcoholic fermentation was affected by maceration time (3, 5, 7, 14 and 21 days) and the addition and kinetics of enzyme preparations (EP). The highest extraction rates were observed for catechin (EXV EP – EXV enzyme preparation and CP EP – Color plus enzyme preparation) and p -hydroxybenzoic acid (Car EP - Caractere enzyme preparation). According to extraction time of the analyzed phenolic compounds, maximal values (ellagic acid, ferulic acid, chlorogenic acid, caffeic acid, naringenin, p -hydroxybenzoic acid, p -coumaric acid, protocatechuic acid, trans -resveratrol, syringic acid, vanillin, and vanillic acid) were obtained on day 15 of maceration with addition of CP EP, with exceptions of gallic acid, catechin, and myricetin. Prolonged maceration times, up to 21 days, showed the most potent DPPH free radical scavenging activity with Car EP and the highest Ferric Reducing Ability of Plasma (FRAP) values with CP EP.
{"title":"Extraction kinetic of some phenolic compounds during Cabernet Sauvignon alcoholic fermentation and antioxidant properties of derived wines","authors":"N. Lisov, A. Petrovic, U. Čakar, M. Jadranin, V. Tešević, Ljiljana Bukarica-Gojković","doi":"10.20450/MJCCE.2020.2060","DOIUrl":"https://doi.org/10.20450/MJCCE.2020.2060","url":null,"abstract":"In this study, we estimated the usage of Cabernet Sauvignon in microvinifications, obtaining wines with increased phenolic compound content. Kinetic extraction of phenolic compounds during alcoholic fermentation was affected by maceration time (3, 5, 7, 14 and 21 days) and the addition and kinetics of enzyme preparations (EP). The highest extraction rates were observed for catechin (EXV EP – EXV enzyme preparation and CP EP – Color plus enzyme preparation) and p -hydroxybenzoic acid (Car EP - Caractere enzyme preparation). According to extraction time of the analyzed phenolic compounds, maximal values (ellagic acid, ferulic acid, chlorogenic acid, caffeic acid, naringenin, p -hydroxybenzoic acid, p -coumaric acid, protocatechuic acid, trans -resveratrol, syringic acid, vanillin, and vanillic acid) were obtained on day 15 of maceration with addition of CP EP, with exceptions of gallic acid, catechin, and myricetin. Prolonged maceration times, up to 21 days, showed the most potent DPPH free radical scavenging activity with Car EP and the highest Ferric Reducing Ability of Plasma (FRAP) values with CP EP.","PeriodicalId":18088,"journal":{"name":"Macedonian Journal of Chemistry and Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49350836","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 : 2020-11-12DOI: 10.20450/mjcce.2020.2152
R. Gulaboski, V. Mirčeski
Protein-film voltammetry (PFV) is considered the simplest methodology to study the electrochemistry of lipophilic redox enzymes in an aqueous environment. By anchoring particular redox enzymes on the working electrode surface, it is possible to get an insight into the mechanism of enzyme action. The PFV methodology enables access to the relevant thermodynamic and kinetic parameters of the enzyme-electrode reaction and enzyme-substrate interactions, which is important to better understand many metabolic pathways in living systems and to delineate the physiological role of enzymes. PFV additionally provides important information which is useful for designing specific biosensors, simple medical devices and bio-fuel cells. In the current review, we focus on some recent achievements of PFV, while presenting some novel protocols that contribute to a better communication between redox enzymes and the working electrode. Insights to several new theoretical models that provide a simple strategy for studying electrode reactions of immobilized enzymes and that enable both kinetic and thermodynamic characterization of enzyme-substrate interactions are also provided. In addition, we give a short overview to several novel voltammetric techniques, derived from the perspective of square-wave voltammetry, which seem to be promising tools for application in PFV.
{"title":"Application of voltammetry in biomedicine - Recent achievements in enzymatic voltammetry","authors":"R. Gulaboski, V. Mirčeski","doi":"10.20450/mjcce.2020.2152","DOIUrl":"https://doi.org/10.20450/mjcce.2020.2152","url":null,"abstract":"Protein-film voltammetry (PFV) is considered the simplest methodology to study the electrochemistry of lipophilic redox enzymes in an aqueous environment. By anchoring particular redox enzymes on the working electrode surface, it is possible to get an insight into the mechanism of enzyme action. The PFV methodology enables access to the relevant thermodynamic and kinetic parameters of the enzyme-electrode reaction and enzyme-substrate interactions, which is important to better understand many metabolic pathways in living systems and to delineate the physiological role of enzymes. PFV additionally provides important information which is useful for designing specific biosensors, simple medical devices and bio-fuel cells. In the current review, we focus on some recent achievements of PFV, while presenting some novel protocols that contribute to a better communication between redox enzymes and the working electrode. Insights to several new theoretical models that provide a simple strategy for studying electrode reactions of immobilized enzymes and that enable both kinetic and thermodynamic characterization of enzyme-substrate interactions are also provided. In addition, we give a short overview to several novel voltammetric techniques, derived from the perspective of square-wave voltammetry, which seem to be promising tools for application in PFV.","PeriodicalId":18088,"journal":{"name":"Macedonian Journal of Chemistry and Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43321697","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 : 2020-10-27DOI: 10.20450/mjcce.2020.2101
R. Davarnejad, J. Azizi, Amir Joodaki, Sepideh Mansoori
The immense volume of highly polluted organic wastewater continuously generated in the beverage industry urges the design of new types of wastewater treatment plants. This study aimed to evaluate the applicability of the electro-Fenton (EF) technique to reduce organic pollution of real effluent from a carbonated soft drink factory. The impact of various process variables like pH, time, current density, H 2 O 2 /Fe 2+ molar ratio, and the volume ratio of H 2 O 2 /soft drink wastewater (SDW) was analyzed using response surface methodology (RSM). The observed responses were in good agreement with predicted values obtained through optimization. The optimum conditions showed a chemical oxygen demand (COD) removal efficiency of 73.07 %, pH of 4.14, time of 41.55 min, current density of 46.12 mA/cm 2 , H 2 O 2 /Fe 2+ molar ratio of 0.9802, and H 2 O 2 /SDW volume fraction of 2.74 ml/l. The EF process was able to effectively diminish the organic pollution, reduce the residence time and, therefore, the operating costs.
{"title":"Optimization of electro-Fenton oxidation of carbonated soft drink industry wastewater using response surface methodology","authors":"R. Davarnejad, J. Azizi, Amir Joodaki, Sepideh Mansoori","doi":"10.20450/mjcce.2020.2101","DOIUrl":"https://doi.org/10.20450/mjcce.2020.2101","url":null,"abstract":"The immense volume of highly polluted organic wastewater continuously generated in the beverage industry urges the design of new types of wastewater treatment plants. This study aimed to evaluate the applicability of the electro-Fenton (EF) technique to reduce organic pollution of real effluent from a carbonated soft drink factory. The impact of various process variables like pH, time, current density, H 2 O 2 /Fe 2+ molar ratio, and the volume ratio of H 2 O 2 /soft drink wastewater (SDW) was analyzed using response surface methodology (RSM). The observed responses were in good agreement with predicted values obtained through optimization. The optimum conditions showed a chemical oxygen demand (COD) removal efficiency of 73.07 %, pH of 4.14, time of 41.55 min, current density of 46.12 mA/cm 2 , H 2 O 2 /Fe 2+ molar ratio of 0.9802, and H 2 O 2 /SDW volume fraction of 2.74 ml/l. The EF process was able to effectively diminish the organic pollution, reduce the residence time and, therefore, the operating costs.","PeriodicalId":18088,"journal":{"name":"Macedonian Journal of Chemistry and Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49321768","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 : 2020-10-26DOI: 10.20450/mjcce.2020.2058
D. K. Behara, Jalajakshi Tammineni, Mukkara Sudha Maheswari
Semiconductor nanomaterials with proper band edge alignments forming “heterostructure” assemblies have significant importance in water splitting, dye degradation, and other electrochemical studies. The formed heterojunction between material phases facilitates fast charge carrier transport and, thereby, improves electrochemical performance in associated processes. Herein, we report a type-II heterostructure combining TiO 2 and ZnO nanomaterials for electrochemical crystal violet dye degradation studies. The rationale in choosing the above materials (TiO 2 , ZnO) in the present study includes stability, lack of toxicity, and high oxidation power, but they also facilitate fast charge carrier movements due to proper band edge alignments, forming a type-II heterostructure assembly. Cyclic voltammetry, combined with ultraviolet-visible analysis, was used to identify the cathodic and anodic peak currents and trace the exact mechanism of dye degradation. The electro-catalytic performance of TiO 2 /ZnO heterostructured materials fabricated on titania (Ti) substrate show higher performance, in comparison to all individual material interfaces, due to synergistic interaction and synchronized charge transport.
{"title":"TiO2/ZnO: Type-II Heterostructures for electrochemical crystal violet dye degradation studies","authors":"D. K. Behara, Jalajakshi Tammineni, Mukkara Sudha Maheswari","doi":"10.20450/mjcce.2020.2058","DOIUrl":"https://doi.org/10.20450/mjcce.2020.2058","url":null,"abstract":"Semiconductor nanomaterials with proper band edge alignments forming “heterostructure” assemblies have significant importance in water splitting, dye degradation, and other electrochemical studies. The formed heterojunction between material phases facilitates fast charge carrier transport and, thereby, improves electrochemical performance in associated processes. Herein, we report a type-II heterostructure combining TiO 2 and ZnO nanomaterials for electrochemical crystal violet dye degradation studies. The rationale in choosing the above materials (TiO 2 , ZnO) in the present study includes stability, lack of toxicity, and high oxidation power, but they also facilitate fast charge carrier movements due to proper band edge alignments, forming a type-II heterostructure assembly. Cyclic voltammetry, combined with ultraviolet-visible analysis, was used to identify the cathodic and anodic peak currents and trace the exact mechanism of dye degradation. The electro-catalytic performance of TiO 2 /ZnO heterostructured materials fabricated on titania (Ti) substrate show higher performance, in comparison to all individual material interfaces, due to synergistic interaction and synchronized charge transport.","PeriodicalId":18088,"journal":{"name":"Macedonian Journal of Chemistry and Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46787455","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 : 2020-10-26DOI: 10.20450/mjcce.2020.2112
Ivana Škugor Rončević, Nives Vladislavić, M. Buzuk, Maša Buljac, A. Lukin
Tin is a moderately corrosion resistant material that is widely used in tinplate for food beverages. However, despite its excellent corrosion resistance, the presence of oxidizing agents enhances tin dissolution. Dissolution of metallic tin, especially from the inside of a can body into the food content has a major influence on the food quality and may cause toxicological effects. To overcome the problem, different chemical compounds are added. The most utilized inhibitors in the food industry are nitrites and nitrates well-known as hazardous to health. The present study aimed to investigate the influence of carboxylic acids on the corrosion resistance of tin since they are present in fruit juices and different foodstuffs. The corrosion protection efficiency of the carboxylate coatings was investigated in a sodium chloride solution using electrochemical and spectroscopic techniques. The structural characteristics of the surface coatings were investigated using the FTIR spectroscopy and optical microscope.
{"title":"Corrosion protection of tin by some carboxylic acids in sodium chloride solution","authors":"Ivana Škugor Rončević, Nives Vladislavić, M. Buzuk, Maša Buljac, A. Lukin","doi":"10.20450/mjcce.2020.2112","DOIUrl":"https://doi.org/10.20450/mjcce.2020.2112","url":null,"abstract":"Tin is a moderately corrosion resistant material that is widely used in tinplate for food beverages. However, despite its excellent corrosion resistance, the presence of oxidizing agents enhances tin dissolution. Dissolution of metallic tin, especially from the inside of a can body into the food content has a major influence on the food quality and may cause toxicological effects. To overcome the problem, different chemical compounds are added. The most utilized inhibitors in the food industry are nitrites and nitrates well-known as hazardous to health. The present study aimed to investigate the influence of carboxylic acids on the corrosion resistance of tin since they are present in fruit juices and different foodstuffs. The corrosion protection efficiency of the carboxylate coatings was investigated in a sodium chloride solution using electrochemical and spectroscopic techniques. The structural characteristics of the surface coatings were investigated using the FTIR spectroscopy and optical microscope.","PeriodicalId":18088,"journal":{"name":"Macedonian Journal of Chemistry and Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46182560","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 : 2020-10-14DOI: 10.20450/mjcce.2020.2073
Öznur Güngör, C. Ben Ali Hassine, Muammer Burç, Serap Titretir Duran
In this study, we investigated the electrochemical modification of a gold electrode using poly(L-phenylalanine) and its applicability for the quantification of resveratrol (RESV). The gold electrode was modified with L-phenylalanine employing cyclic voltammetry (CV) in aqueous solution. The detection of RESV with the modified electrode was investigated by square wave voltammetry (SWV) in a phosphate buffer solution (PBS) (pH = 1.2). The analytical calibration curve for RESV showed a linear response with concentration in the oxidation peak current range from 50 to 1000 µM, with a limit of detection (LOD) of 35.16 µM and limit of quantitation (LOQ) of 105.5 µM. The application of the prepared electrochemical sensor was carried out with a standard addition method in red wine samples.
{"title":"Voltammetric determination of resveratrol using poly(l-phenylalanine)-modified gold electrode","authors":"Öznur Güngör, C. Ben Ali Hassine, Muammer Burç, Serap Titretir Duran","doi":"10.20450/mjcce.2020.2073","DOIUrl":"https://doi.org/10.20450/mjcce.2020.2073","url":null,"abstract":"In this study, we investigated the electrochemical modification of a gold electrode using poly(L-phenylalanine) and its applicability for the quantification of resveratrol (RESV). The gold electrode was modified with L-phenylalanine employing cyclic voltammetry (CV) in aqueous solution. The detection of RESV with the modified electrode was investigated by square wave voltammetry (SWV) in a phosphate buffer solution (PBS) (pH = 1.2). The analytical calibration curve for RESV showed a linear response with concentration in the oxidation peak current range from 50 to 1000 µM, with a limit of detection (LOD) of 35.16 µM and limit of quantitation (LOQ) of 105.5 µM. The application of the prepared electrochemical sensor was carried out with a standard addition method in red wine samples.","PeriodicalId":18088,"journal":{"name":"Macedonian Journal of Chemistry and Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46849987","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 : 2020-10-14DOI: 10.20450/mjcce.2020.2088
F. Brown, S. Burge, K. Hristovski, R. Burge, Evan Taylor, D. Hoffman
Considering that toxic metals can affect metabolic processes in microorganisms adversely, it can be hypothesized that these metals in water matrices would induce a decrease in metabolic activity of the biofilm microorganisms populating the surface of a sensing electrode, which could be registered as a change in the open-circuit potential (OCP) generated by the biofilm microorganisms. The goal of this study was to test this hypothesis and demonstrate the underlying principle that microbial potentiometric sensor (MPS) technology could be used for long-term and real-time monitoring and detection of rapid changes in metal concentrations in realistic aquatic environments. To address the goal, four objective were addressed: (1) a batch reactor with three graphite-based MPS electrodes was fabricated; (2) a set of single-ion solutions and one multiple ion solution were prepared reflecting realistic concentrations of metals found in electroplating wastewaters; (3) the responses of the MPS to the simultaneous presence of multiple toxic metal ions in a single solution were measured; and (4) the changes of the MPS signals to the presence of individual metal ion solutions were examined. While the hypothesis was validated, the study also revealed that the MPS was sufficiently sensitive to not only detect, but also quantify, toxic metal ion concentrations in aqueous solutions. The coefficients of determination, which were R 2 >0.995, and responsiveness of Cd>Pb>Ag>Ni> Zn. The study provides valuable information for enforcement agents, environmental professionals, and wastewater treatment operators, so toxic metal pollution and its detrimental impacts can be prevented and mitigated.
{"title":"Microbial potentiometric sensor technology for real-time detecting and monitoring of toxic metals in aquatic matrices","authors":"F. Brown, S. Burge, K. Hristovski, R. Burge, Evan Taylor, D. Hoffman","doi":"10.20450/mjcce.2020.2088","DOIUrl":"https://doi.org/10.20450/mjcce.2020.2088","url":null,"abstract":"Considering that toxic metals can affect metabolic processes in microorganisms adversely, it can be hypothesized that these metals in water matrices would induce a decrease in metabolic activity of the biofilm microorganisms populating the surface of a sensing electrode, which could be registered as a change in the open-circuit potential (OCP) generated by the biofilm microorganisms. The goal of this study was to test this hypothesis and demonstrate the underlying principle that microbial potentiometric sensor (MPS) technology could be used for long-term and real-time monitoring and detection of rapid changes in metal concentrations in realistic aquatic environments. To address the goal, four objective were addressed: (1) a batch reactor with three graphite-based MPS electrodes was fabricated; (2) a set of single-ion solutions and one multiple ion solution were prepared reflecting realistic concentrations of metals found in electroplating wastewaters; (3) the responses of the MPS to the simultaneous presence of multiple toxic metal ions in a single solution were measured; and (4) the changes of the MPS signals to the presence of individual metal ion solutions were examined. While the hypothesis was validated, the study also revealed that the MPS was sufficiently sensitive to not only detect, but also quantify, toxic metal ion concentrations in aqueous solutions. The coefficients of determination, which were R 2 >0.995, and responsiveness of Cd>Pb>Ag>Ni> Zn. The study provides valuable information for enforcement agents, environmental professionals, and wastewater treatment operators, so toxic metal pollution and its detrimental impacts can be prevented and mitigated.","PeriodicalId":18088,"journal":{"name":"Macedonian Journal of Chemistry and Chemical Engineering","volume":"39 1","pages":"119-127"},"PeriodicalIF":1.0,"publicationDate":"2020-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43558955","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 : 2020-10-14DOI: 10.20450/mjcce.2020.1978
M. L. Sall, A. Diaw, D. Gningue-Sall, M. Oturan, J. Aaron
A new electrosynthesized, fluorescent 4-amino-3-hydroxynaphthalene-1-sulfonic acid-doped polypyrrole (AHNSA-PPy) was used for the detection of Cr(VI), Pb(II) and Cd(II) heavy metallic ions. The optical properties of AHNSA-PPy were studied by UV-VIS absorption and fluorescence spectrometry in diluted DMSO solutions. UV-VIS spectrum showed a main band at 260 nm, a moderate band at 240 nm, and shoulders at 285, 295, 320 and 360 nm, whereas the fluorescence spectrum presented an excitation peak at 330 nm and a main emission peak at 390 nm with a shoulder at 295 nm. The effects of heavy metallic ions, including Cr(VI), Pb(II), and Cd(II), on the AHNSA-PPy UV-VIS absorption and fluorescence spectra were investigated. AHNSA-PPy fluorescence spectra were strongly quenched upon increasing the Cr(VI), Pb(II) and Cd(II) concentrations. Linear Stern-Volmer relationships were established, and polynomial equations for Pb(II) and Cd(II) were obeyed, indicating the existence of a AHNSA-PPy dynamic fluorescence quenching mechanism for Cr(VI) and a combination of dynamic and static fluorescence quenching for Pb(II) and Cd(II). The AHNSA-PPy sensor showed high sensitivity for fluorescence detection of the three heavy metallic ions, with very low limits of detection (3σ) of 1.4 nM for Cr(VI), 2.7 nM for Cd(II) and 2.6 nM for Pb(II). Therefore, this very sensitive quenching fluorimetric sensor is proposed for the detection of trace, toxic heavy metallic ions in the environment.
{"title":"Highly sensitive detection of Cr(VI), Pb(II) and Cd(II) ions by a new fluorescent sensor based on 4-amino-3-hydroxynaphthalene sulfonic acid-doped polypyrrole","authors":"M. L. Sall, A. Diaw, D. Gningue-Sall, M. Oturan, J. Aaron","doi":"10.20450/mjcce.2020.1978","DOIUrl":"https://doi.org/10.20450/mjcce.2020.1978","url":null,"abstract":"A new electrosynthesized, fluorescent 4-amino-3-hydroxynaphthalene-1-sulfonic acid-doped polypyrrole (AHNSA-PPy) was used for the detection of Cr(VI), Pb(II) and Cd(II) heavy metallic ions. The optical properties of AHNSA-PPy were studied by UV-VIS absorption and fluorescence spectrometry in diluted DMSO solutions. UV-VIS spectrum showed a main band at 260 nm, a moderate band at 240 nm, and shoulders at 285, 295, 320 and 360 nm, whereas the fluorescence spectrum presented an excitation peak at 330 nm and a main emission peak at 390 nm with a shoulder at 295 nm. The effects of heavy metallic ions, including Cr(VI), Pb(II), and Cd(II), on the AHNSA-PPy UV-VIS absorption and fluorescence spectra were investigated. AHNSA-PPy fluorescence spectra were strongly quenched upon increasing the Cr(VI), Pb(II) and Cd(II) concentrations. Linear Stern-Volmer relationships were established, and polynomial equations for Pb(II) and Cd(II) were obeyed, indicating the existence of a AHNSA-PPy dynamic fluorescence quenching mechanism for Cr(VI) and a combination of dynamic and static fluorescence quenching for Pb(II) and Cd(II). The AHNSA-PPy sensor showed high sensitivity for fluorescence detection of the three heavy metallic ions, with very low limits of detection (3σ) of 1.4 nM for Cr(VI), 2.7 nM for Cd(II) and 2.6 nM for Pb(II). Therefore, this very sensitive quenching fluorimetric sensor is proposed for the detection of trace, toxic heavy metallic ions in the environment.","PeriodicalId":18088,"journal":{"name":"Macedonian Journal of Chemistry and Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47466337","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 : 2020-10-14DOI: 10.20450/mjcce.2020.1984
N. Chukanov, O. Kazheva, N. A. Chervonnaya, D. Varlamov, V. Ermolaeva, I. Pekov, G. Shilov
Crystals of the natural zeolite amicite, ideally K 4 Na 4 (Al 8 Si 8 O 32 )·10H 2 O, were ion-exchanged in the reactions with 0.1 N aqueous solutions of AgNO 3 , RbNO 3 , CsNO 3 and Pb(NO 3 ) 2 at 363 K for 24 h. Under these conditions, Cs + substitutes K + whereas the most part of Na + remains unexchanged; Rb + partly substitutes both Na + and K + ; Pb 2+ and Ag + completely substitute Na + and K + . All the compounds are monoclinic. The Cs- and Rb-substituted samples have unit-cell parameters close to those of initial amicite. The exchange of Na + and K + for Ag + is accompanied by a significant decrease of the unit-cell volume. The unit-cell parameter c of Pb-amicite is nearly threefold larger than the c parameter of initial amicite. Infrared spectra show that framework topology is preserved during the ion exchange. The crystal structures of initial and Cs-exchanged amicites have been solved by direct methods.
{"title":"Ion-exchange properties of the natural zeolite amicite","authors":"N. Chukanov, O. Kazheva, N. A. Chervonnaya, D. Varlamov, V. Ermolaeva, I. Pekov, G. Shilov","doi":"10.20450/mjcce.2020.1984","DOIUrl":"https://doi.org/10.20450/mjcce.2020.1984","url":null,"abstract":"Crystals of the natural zeolite amicite, ideally K 4 Na 4 (Al 8 Si 8 O 32 )·10H 2 O, were ion-exchanged in the reactions with 0.1 N aqueous solutions of AgNO 3 , RbNO 3 , CsNO 3 and Pb(NO 3 ) 2 at 363 K for 24 h. Under these conditions, Cs + substitutes K + whereas the most part of Na + remains unexchanged; Rb + partly substitutes both Na + and K + ; Pb 2+ and Ag + completely substitute Na + and K + . All the compounds are monoclinic. The Cs- and Rb-substituted samples have unit-cell parameters close to those of initial amicite. The exchange of Na + and K + for Ag + is accompanied by a significant decrease of the unit-cell volume. The unit-cell parameter c of Pb-amicite is nearly threefold larger than the c parameter of initial amicite. Infrared spectra show that framework topology is preserved during the ion exchange. The crystal structures of initial and Cs-exchanged amicites have been solved by direct methods.","PeriodicalId":18088,"journal":{"name":"Macedonian Journal of Chemistry and Chemical Engineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45028356","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 : 2020-06-11DOI: 10.20450/mjcce.2020.1903
A. Ibraliu, A. Doko, Avni Hajdari, N. Gruda, Z. Šatović, Ivana Cvetkovikj Karanfilova, G. Stefkov
Essential oils from seven populations of Dalmatian sage from the North of Albania were extracted and analyzed according European Pharmacopeia 7.0. The yield differed from 1.95 to 2.75% v/w. The GC-FID-MS analysis of the sage oil revealed 42 constituents. Camphor (20.50-29.74%), followed by α-thujone (19.87-24.29%), 1,8-cineole (6.88-12.64%) and β-thujone (4.00-9.14%) were predominant constituents in all analyzed populations, representing 55.70-68.00% of the total components. All of the analyzed sage populations from northern Albania comply with ISO 6571/2008 standard and European Pharmacopeia 7.0. for Dalmatian sage essential oil content, while only four populations met the requirements of the ISO 9909/1997 standard for Dalmatian sage essential oil’s composition.
{"title":"Essential Oils Chemical Variability of Seven Populations of Salvia Officinalis L. In North of Albania","authors":"A. Ibraliu, A. Doko, Avni Hajdari, N. Gruda, Z. Šatović, Ivana Cvetkovikj Karanfilova, G. Stefkov","doi":"10.20450/mjcce.2020.1903","DOIUrl":"https://doi.org/10.20450/mjcce.2020.1903","url":null,"abstract":"Essential oils from seven populations of Dalmatian sage from the North of Albania were extracted and analyzed according European Pharmacopeia 7.0. The yield differed from 1.95 to 2.75% v/w. The GC-FID-MS analysis of the sage oil revealed 42 constituents. Camphor (20.50-29.74%), followed by α-thujone (19.87-24.29%), 1,8-cineole (6.88-12.64%) and β-thujone (4.00-9.14%) were predominant constituents in all analyzed populations, representing 55.70-68.00% of the total components. All of the analyzed sage populations from northern Albania comply with ISO 6571/2008 standard and European Pharmacopeia 7.0. for Dalmatian sage essential oil content, while only four populations met the requirements of the ISO 9909/1997 standard for Dalmatian sage essential oil’s composition.","PeriodicalId":18088,"journal":{"name":"Macedonian Journal of Chemistry and Chemical Engineering","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42685852","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：