Pub Date : 2019-07-21DOI: 10.26850/1678-4618EQJ.V44.3.2019.P43-49
A. A. Madeira
This article was elaborated in an approach to the liquid-liquid equilibrium of the extraction process of ethanoic acid (C2H4O2) in aqueous phase using ethyl ethanoate as solvent. The liquid-liquid extraction was modeled by the construction of a ternary phase diagram for the water-ethanoic acid- ethyl ethanoate system with the aid of the Origin software. The equilibrium data were obtained experimentally by titration at room temperature (298.15 K) and atmospheric pressure (101325 Pa) using four mixtures of water, ethanoic acid, and ethyl ethanoate. The determination of the composition of the extract and residue portions in the equilibrium of each mixture by of the tie-lines method allowed to examine the percentages of liquid-liquid extraction achieved. The distribution coefficients and separation factors calculated made it possible an evaluation of the distribution and of the mutual solubility of the solute in the aqueous and organic phases. The results showed a good performance of ethyl ethanoate in the extraction of ethanoic acid for concentrations of solute until 16% of the feed.
{"title":"Application of a ternary phase diagram to the liquid-liquid extraction of ethanoic acid using ethyl ethanoate","authors":"A. A. Madeira","doi":"10.26850/1678-4618EQJ.V44.3.2019.P43-49","DOIUrl":"https://doi.org/10.26850/1678-4618EQJ.V44.3.2019.P43-49","url":null,"abstract":"This article was elaborated in an approach to the liquid-liquid equilibrium of the extraction process of ethanoic acid (C2H4O2) in aqueous phase using ethyl ethanoate as solvent. The liquid-liquid extraction was modeled by the construction of a ternary phase diagram for the water-ethanoic acid- ethyl ethanoate system with the aid of the Origin software. The equilibrium data were obtained experimentally by titration at room temperature (298.15 K) and atmospheric pressure (101325 Pa) using four mixtures of water, ethanoic acid, and ethyl ethanoate. The determination of the composition of the extract and residue portions in the equilibrium of each mixture by of the tie-lines method allowed to examine the percentages of liquid-liquid extraction achieved. The distribution coefficients and separation factors calculated made it possible an evaluation of the distribution and of the mutual solubility of the solute in the aqueous and organic phases. The results showed a good performance of ethyl ethanoate in the extraction of ethanoic acid for concentrations of solute until 16% of the feed.","PeriodicalId":11506,"journal":{"name":"Eclética Química Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74512828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-04DOI: 10.26850/1678-4618EQJ.V44.3.2019.P11-19
Filipe Boccato Payolla, A. Massabni, C. Orvig
Radiopharmaceuticals are radioactive compounds which have a bound radionuclide in their structure, whose purpose is directing the radionuclide to a location to be treated or to obtain images. Nuclear medicine is the medical specialty that employs radiopharmaceuticals, which has presented itself as a tremendously useful ally for medicine assisting in various diagnoses and treatments, especially for cancer. The general objective of this work is to identify the main radionuclides and metal complexes currently used as radiopharmaceuticals. The main metal complexes used as radiopharmaceuticals are compounds of technetium (99mTc) like sodium pertechnetate and methylenediphosphonate MDP-99mTc and other compounds of indium (111In), thallium (201Tl), gallium (67Ga, 68Ga), iodine (123I and 131I), chromium (51Cr), sulphur (35S), phosphorus (32P), fluorine (as fluorodeoxyglucose, 18F-FDG and sodium fluorine, Na18F), which are widely used in the nuclear medicine for diagnosis by imaging. They have been of great importance for the early diagnosis of numerous diseases, mainly cancer.Currently, technetium compounds are the majority of radiopharmaceuticals used in all countries. In Brazil, Institute of Energy and Nuclear Research (IPEN) is one of the most important distributors of radiopharmaceuticals, producing, importing and distributing them to clinics and hospitals over the country.
{"title":"Radiopharmaceuticals for diagnosis in nuclear medicine: a short review","authors":"Filipe Boccato Payolla, A. Massabni, C. Orvig","doi":"10.26850/1678-4618EQJ.V44.3.2019.P11-19","DOIUrl":"https://doi.org/10.26850/1678-4618EQJ.V44.3.2019.P11-19","url":null,"abstract":"Radiopharmaceuticals are radioactive compounds which have a bound radionuclide in their structure, whose purpose is directing the radionuclide to a location to be treated or to obtain images. Nuclear medicine is the medical specialty that employs radiopharmaceuticals, which has presented itself as a tremendously useful ally for medicine assisting in various diagnoses and treatments, especially for cancer. The general objective of this work is to identify the main radionuclides and metal complexes currently used as radiopharmaceuticals. The main metal complexes used as radiopharmaceuticals are compounds of technetium (99mTc) like sodium pertechnetate and methylenediphosphonate MDP-99mTc and other compounds of indium (111In), thallium (201Tl), gallium (67Ga, 68Ga), iodine (123I and 131I), chromium (51Cr), sulphur (35S), phosphorus (32P), fluorine (as fluorodeoxyglucose, 18F-FDG and sodium fluorine, Na18F), which are widely used in the nuclear medicine for diagnosis by imaging. They have been of great importance for the early diagnosis of numerous diseases, mainly cancer.Currently, technetium compounds are the majority of radiopharmaceuticals used in all countries. In Brazil, Institute of Energy and Nuclear Research (IPEN) is one of the most important distributors of radiopharmaceuticals, producing, importing and distributing them to clinics and hospitals over the country.","PeriodicalId":11506,"journal":{"name":"Eclética Química Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81425796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-04-25DOI: 10.26850/1678-4618EQJ.V44.2.2019.P45-52
H. Naeem, F. Abdullah
In recent years, the demand of high-performance and light-weight materials was increasing for industrial applications. The present research aims to study microstructural and mechanical properties of aluminum matrix hybrid reinforced 6-12 wt.% of garnet under the effects of materials chill casting during the manufacturing aluminum matrix composite. In this research work, metallic mold and no chills were used. In order to evaluate the quality of the chill end casting microstructure, hardness, and tensile tests were conducted on the prepared composite specimens. Aluminum matrix composites underwent the chill casting process have been examined using the optical microscope, scanning electron microscopy and X-ray diffraction. Microstructure outcomes of the casted Al-composites alloy indicated that having precipitations (Al2Si, AlCuMg2Si) and Garnet particulates hard within the Al-matrix. The results showed that the copper chill casting is the better one in terms of improving the mechanical properties because of its high volumetric heat capacity. Aluminum composite with addition of 9% Garnet composite produced via copper chill casting exhibits better mechanical properties.
{"title":"Effects of garnet particles and chill casting conditions on properties of aluminum matrix hybrid composites","authors":"H. Naeem, F. Abdullah","doi":"10.26850/1678-4618EQJ.V44.2.2019.P45-52","DOIUrl":"https://doi.org/10.26850/1678-4618EQJ.V44.2.2019.P45-52","url":null,"abstract":"In recent years, the demand of high-performance and light-weight materials was increasing for industrial applications. The present research aims to study microstructural and mechanical properties of aluminum matrix hybrid reinforced 6-12 wt.% of garnet under the effects of materials chill casting during the manufacturing aluminum matrix composite. In this research work, metallic mold and no chills were used. In order to evaluate the quality of the chill end casting microstructure, hardness, and tensile tests were conducted on the prepared composite specimens. Aluminum matrix composites underwent the chill casting process have been examined using the optical microscope, scanning electron microscopy and X-ray diffraction. Microstructure outcomes of the casted Al-composites alloy indicated that having precipitations (Al2Si, AlCuMg2Si) and Garnet particulates hard within the Al-matrix. The results showed that the copper chill casting is the better one in terms of improving the mechanical properties because of its high volumetric heat capacity. Aluminum composite with addition of 9% Garnet composite produced via copper chill casting exhibits better mechanical properties.","PeriodicalId":11506,"journal":{"name":"Eclética Química Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90659549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-04-25DOI: 10.26850/1678-4618EQJ.V44.2.2019.P11-25
M. Santos, P. A. M. Nascimento, W. N. Guedes, E. Pereira-Filho, É. R. Filletti, F. Pereira
A compilation of papers published between 2014 and 2018 was evaluated. Many papers related to multivariate calibration and classification have been reported, as well as, design of experiments applications and artificial intelligence methods. Some applications were highlighted, as medical and pharmaceutical, food analysis, fuels, biological and forensic for the chemometric techniques on this review. Most studies are related to developing methods for practical solutions in industry or routine analysis. A promising scenario is shown considering the number of published papers: a total of 832 for this period using the keywords, multivariate classification, multivariate calibration, analysis, chemometrics, prediction, analytical chemistry, artificial neural networks (ANN), design of experiments (DoE) and factorial design. An useful overview for Analytical Chemistry researchers´ combined with Chemometrics is presented in this review.
{"title":"Chemometrics in analytical chemistry – an overview of applications from 2014 to 2018","authors":"M. Santos, P. A. M. Nascimento, W. N. Guedes, E. Pereira-Filho, É. R. Filletti, F. Pereira","doi":"10.26850/1678-4618EQJ.V44.2.2019.P11-25","DOIUrl":"https://doi.org/10.26850/1678-4618EQJ.V44.2.2019.P11-25","url":null,"abstract":"A compilation of papers published between 2014 and 2018 was evaluated. Many papers related to multivariate calibration and classification have been reported, as well as, design of experiments applications and artificial intelligence methods. Some applications were highlighted, as medical and pharmaceutical, food analysis, fuels, biological and forensic for the chemometric techniques on this review. Most studies are related to developing methods for practical solutions in industry or routine analysis. A promising scenario is shown considering the number of published papers: a total of 832 for this period using the keywords, multivariate classification, multivariate calibration, analysis, chemometrics, prediction, analytical chemistry, artificial neural networks (ANN), design of experiments (DoE) and factorial design. An useful overview for Analytical Chemistry researchers´ combined with Chemometrics is presented in this review.","PeriodicalId":11506,"journal":{"name":"Eclética Química Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86634517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-04-25DOI: 10.26850/1678-4618EQJ.V44.2.2019.P37-44
C. M. Bossu, V. Carioni, J. Naozuka, P. Oliveira, C. Nomura
This work describes a simple and rapid screening method for direct speciation of arsenobetaine (AsB) in tuna fish tissue and total As in tuna fish tissue and robalo liver using SLS-GF AAS. All procedures were proposed after careful optimization of pyrolysis and evaluation of chemical modifiers. Best results for total As were acquired using 25 µg Pd + 15 µg Mg + 0.1% w/v Triton X-100 in tuna fish (4.4 ± 0.3 mg kg-1) and 100 µg Pd + 0.1 % w/v Triton X-100 solution in robalo liver (10.3 ± 0.6 mg kg-1) as chemical modifiers. The direct speciation of AsB (3.6 ± 0.4 mg kg-1) in tuna fish was achieved when 5 µg Pd + 3 µg Mg + 0.1% w/v Triton X-100 was used as a chemical modifier. Accuracy was verified using a tuna fish certified reference material (CRM BCR 627), with statistically equivalent concentrations (Student’s t-test) for both total As and AsB.
{"title":"Direct determination of arsenobetaine and total As in robalo fish liver and tuna fish candidate reference material by slurry sampling graphite furnace atomic absorption spectrometry (SLS-GF AAS)","authors":"C. M. Bossu, V. Carioni, J. Naozuka, P. Oliveira, C. Nomura","doi":"10.26850/1678-4618EQJ.V44.2.2019.P37-44","DOIUrl":"https://doi.org/10.26850/1678-4618EQJ.V44.2.2019.P37-44","url":null,"abstract":"This work describes a simple and rapid screening method for direct speciation of arsenobetaine (AsB) in tuna fish tissue and total As in tuna fish tissue and robalo liver using SLS-GF AAS. All procedures were proposed after careful optimization of pyrolysis and evaluation of chemical modifiers. Best results for total As were acquired using 25 µg Pd + 15 µg Mg + 0.1% w/v Triton X-100 in tuna fish (4.4 ± 0.3 mg kg-1) and 100 µg Pd + 0.1 % w/v Triton X-100 solution in robalo liver (10.3 ± 0.6 mg kg-1) as chemical modifiers. The direct speciation of AsB (3.6 ± 0.4 mg kg-1) in tuna fish was achieved when 5 µg Pd + 3 µg Mg + 0.1% w/v Triton X-100 was used as a chemical modifier. Accuracy was verified using a tuna fish certified reference material (CRM BCR 627), with statistically equivalent concentrations (Student’s t-test) for both total As and AsB.","PeriodicalId":11506,"journal":{"name":"Eclética Química Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89213859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-04-25DOI: 10.26850/1678-4618EQJ.V44.2.2019.P53-55
A. Massabni, Cristo Bladimiros Melios
Binary complexes of general formula CoCl2L2, where L = triphenylphosphine oxide (TPPO), benzyldiphenylphosphine oxide (BDPPO), dibenzylphenylphosphine oxide (DBPPO) and tribenzylphosphine oxide (TBPO) were considered concerning X-ray structural data for the complexes in the solid state and their stability constants in acetone solution. Compatibility between structural data and stability constants are pointed out. Previous investigations showed that in acetone medium, with CoCl2 as reference acceptor, the following basicity order is obeyed: TBPO > DBPPO > BDPPO > TPPO. This sequence is supported by X-ray diffraction data of the solid complexes and by electrolytic conductance values for these complexes both in acetone and in nitromethane media.
{"title":"Cobalt(II) chloride complexes with some phosphine oxides: compatibility between structural data for the solid complexes and their stability constants in acetone medium","authors":"A. Massabni, Cristo Bladimiros Melios","doi":"10.26850/1678-4618EQJ.V44.2.2019.P53-55","DOIUrl":"https://doi.org/10.26850/1678-4618EQJ.V44.2.2019.P53-55","url":null,"abstract":"Binary complexes of general formula CoCl2L2, where L = triphenylphosphine oxide (TPPO), benzyldiphenylphosphine oxide (BDPPO), dibenzylphenylphosphine oxide (DBPPO) and tribenzylphosphine oxide (TBPO) were considered concerning X-ray structural data for the complexes in the solid state and their stability constants in acetone solution. Compatibility between structural data and stability constants are pointed out. Previous investigations showed that in acetone medium, with CoCl2 as reference acceptor, the following basicity order is obeyed: TBPO > DBPPO > BDPPO > TPPO. This sequence is supported by X-ray diffraction data of the solid complexes and by electrolytic conductance values for these complexes both in acetone and in nitromethane media.","PeriodicalId":11506,"journal":{"name":"Eclética Química Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75242987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-04-25DOI: 10.26850/1678-4618EQJ.V44.2.2019.P26-36
Gustavo Pereira Saito, Mariana Bizari, M. Cebim, M. Correa, M. Jafelicci Junior, M. Davolos
Sunscreen formulations containing inorganic/organic filters or mixture of them were synthesized by oil/water dispersion. The viscosity measurements show that sunscreen formulations are time-dependent non-newtonian fluids. In the CIELab color diagram, the white and/or beige colors presented by formulations do not compromise the aesthetics of the cosmetic product. UV-VIS absorption spectra show that sunscreen creams have high UV shielding ability, mainly the formulations containing inorganic and organic filters mixtures, which provide in vitro SPF and critical wavelength values recommended for UV protection.
{"title":"Study of the colloidal stability and optical properties of sunscreen creams","authors":"Gustavo Pereira Saito, Mariana Bizari, M. Cebim, M. Correa, M. Jafelicci Junior, M. Davolos","doi":"10.26850/1678-4618EQJ.V44.2.2019.P26-36","DOIUrl":"https://doi.org/10.26850/1678-4618EQJ.V44.2.2019.P26-36","url":null,"abstract":"Sunscreen formulations containing inorganic/organic filters or mixture of them were synthesized by oil/water dispersion. The viscosity measurements show that sunscreen formulations are time-dependent non-newtonian fluids. In the CIELab color diagram, the white and/or beige colors presented by formulations do not compromise the aesthetics of the cosmetic product. UV-VIS absorption spectra show that sunscreen creams have high UV shielding ability, mainly the formulations containing inorganic and organic filters mixtures, which provide in vitro SPF and critical wavelength values recommended for UV protection.","PeriodicalId":11506,"journal":{"name":"Eclética Química Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84677763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-28DOI: 10.26850/1678-4618EQJ.V44.1.2019.P62-74
V. Costa, Ariane Maciel Neiva, E. Pereira-Filho
This study proposes a new and simple method for Cr speciation and Cr(VI) determination in leather samples using digital images. The experiments were performed using a mobile phone and a free app called PhotoMetrix that was used to obtain and process data. The results obtained from PhotoMetrix were compared to reference methods using UV−Vis spectroscopy. A statistical evaluation between both proposed and the reference methods using two-sample t-test did not show a significant difference at a 95% confidence level. Bovine leather samples (4 samples) tanned with Cr salts and ovine leather samples (3 samples) tanned with vegetable tannin were analyzed. The proposed method presented limits of detection (LOD) and quantification (LOQ) of 0.6 and 2 mg/kg, respectively. In addition, the proposed method using PhotoMetrix and digital images can provide undergraduate students an opportunity to learn topics such as quantitative analyses, environmental chemistry, speciation chemistry, image processing and treatment of statistical data. The results demonstrated that the proposed method can be applied to routine analyses and in experimental analytical chemistry courses.
{"title":"Chromium speciation in leather samples: an experiment using digital images, mobile phone and environmental concepts","authors":"V. Costa, Ariane Maciel Neiva, E. Pereira-Filho","doi":"10.26850/1678-4618EQJ.V44.1.2019.P62-74","DOIUrl":"https://doi.org/10.26850/1678-4618EQJ.V44.1.2019.P62-74","url":null,"abstract":"This study proposes a new and simple method for Cr speciation and Cr(VI) determination in leather samples using digital images. The experiments were performed using a mobile phone and a free app called PhotoMetrix that was used to obtain and process data. The results obtained from PhotoMetrix were compared to reference methods using UV−Vis spectroscopy. A statistical evaluation between both proposed and the reference methods using two-sample t-test did not show a significant difference at a 95% confidence level. Bovine leather samples (4 samples) tanned with Cr salts and ovine leather samples (3 samples) tanned with vegetable tannin were analyzed. The proposed method presented limits of detection (LOD) and quantification (LOQ) of 0.6 and 2 mg/kg, respectively. In addition, the proposed method using PhotoMetrix and digital images can provide undergraduate students an opportunity to learn topics such as quantitative analyses, environmental chemistry, speciation chemistry, image processing and treatment of statistical data. The results demonstrated that the proposed method can be applied to routine analyses and in experimental analytical chemistry courses.","PeriodicalId":11506,"journal":{"name":"Eclética Química Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81193475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-28DOI: 10.26850/1678-4618EQJ.V44.1.2019.P53-61
Javier Ernesto Vilasó Cadre, Alejandro Céspedes Martínez, M. A. A. Pérez, José Alejandro Baeza Reyes
A voltammetric method for the cadmium quantification was developed using minimal instrumentation. A manual homemade potentiostat for linear voltammetry was used. An Ag reference electrode and auxiliary and working electrodes of writing graphite were employed for the electroanalysis. The electrolytic conditions for the quantification were stablished. Linearity, detection and quantification limits, precision and accuracy were evaluated. The conditions for the quantification were 1 mol/L of KCl as supporting electrolyte, pH 5 and 10 s for the current sampling. The range of quantification was from 10-3 to 1.5∙10-2 mol/L. The linear correlation (r), determination (R2) and adjusted (R2adj.) coefficients were 0.9986, 0.9972 and 0.9970. The detection and quantification limits were 3∙10-4 mol/L and 10-3 mol/L. Results showed an acceptable repeatability, with coefficients of variation from 1.5 to 5.8 % depending of the concentration. Uncertainty associated with the cadmium concentration was in the range of 1.2∙10-4 to 7∙10-5 mol/L, diminishing with the increasing of the concentration. A good accuracy was observed, with recoveries between 86.84 and 109.64 %.
{"title":"Voltammetric method for the quantification of cadmium using non-commercial electrodes and minimal instrumentation","authors":"Javier Ernesto Vilasó Cadre, Alejandro Céspedes Martínez, M. A. A. Pérez, José Alejandro Baeza Reyes","doi":"10.26850/1678-4618EQJ.V44.1.2019.P53-61","DOIUrl":"https://doi.org/10.26850/1678-4618EQJ.V44.1.2019.P53-61","url":null,"abstract":"A voltammetric method for the cadmium quantification was developed using minimal instrumentation. A manual homemade potentiostat for linear voltammetry was used. An Ag reference electrode and auxiliary and working electrodes of writing graphite were employed for the electroanalysis. The electrolytic conditions for the quantification were stablished. Linearity, detection and quantification limits, precision and accuracy were evaluated. The conditions for the quantification were 1 mol/L of KCl as supporting electrolyte, pH 5 and 10 s for the current sampling. The range of quantification was from 10-3 to 1.5∙10-2 mol/L. The linear correlation (r), determination (R2) and adjusted (R2adj.) coefficients were 0.9986, 0.9972 and 0.9970. The detection and quantification limits were 3∙10-4 mol/L and 10-3 mol/L. Results showed an acceptable repeatability, with coefficients of variation from 1.5 to 5.8 % depending of the concentration. Uncertainty associated with the cadmium concentration was in the range of 1.2∙10-4 to 7∙10-5 mol/L, diminishing with the increasing of the concentration. A good accuracy was observed, with recoveries between 86.84 and 109.64 %.","PeriodicalId":11506,"journal":{"name":"Eclética Química Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86089073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-28DOI: 10.26850/1678-4618EQJ.V44.1.2019.P11-39
H. Louis, O. Akakuru, Philip Monday, O. O. Funmilayo
Significantly, global warming which is caused by CO2 emission and energy shortage are global problems resulting from artificial photosynthesis because it required many functions (light harvesting, Z water, and oxidation scheme). Therefore, photocatalytic systems development for CO2 reduction is germane in this field. Metal complexes molecular catalyst have become prevalent homogeneous catalysts for carbon dioxide (CO2) photocatalytic reduction since it was initially known as CO2 reduction catalysts in the 70s and the 80s, while utmost part involved macrocyclic cobalt(II) and nickel(II) complexes. This review article presents a broad understanding on some active catalysts recently reported as a metal complex molecular catalytic schemes for CO2 reduction, alongside catalytic activity, stability, selectivity under electro-reduction, and photoreduction circumstances. The progress of in situ spectroelectrochemical methods, typically supported via theoretical calculations, helped to access this know-how by providing information which enabled researchers to acquire more in-depth perception into unveiling the catalytic reaction and mechanisms intermediates.
{"title":"A review on the state-of-the-art advances for CO2 electro-chemical reduction using metal complex molecular catalysts","authors":"H. Louis, O. Akakuru, Philip Monday, O. O. Funmilayo","doi":"10.26850/1678-4618EQJ.V44.1.2019.P11-39","DOIUrl":"https://doi.org/10.26850/1678-4618EQJ.V44.1.2019.P11-39","url":null,"abstract":"Significantly, global warming which is caused by CO2 emission and energy shortage are global problems resulting from artificial photosynthesis because it required many functions (light harvesting, Z water, and oxidation scheme). Therefore, photocatalytic systems development for CO2 reduction is germane in this field. Metal complexes molecular catalyst have become prevalent homogeneous catalysts for carbon dioxide (CO2) photocatalytic reduction since it was initially known as CO2 reduction catalysts in the 70s and the 80s, while utmost part involved macrocyclic cobalt(II) and nickel(II) complexes. This review article presents a broad understanding on some active catalysts recently reported as a metal complex molecular catalytic schemes for CO2 reduction, alongside catalytic activity, stability, selectivity under electro-reduction, and photoreduction circumstances. The progress of in situ spectroelectrochemical methods, typically supported via theoretical calculations, helped to access this know-how by providing information which enabled researchers to acquire more in-depth perception into unveiling the catalytic reaction and mechanisms intermediates.","PeriodicalId":11506,"journal":{"name":"Eclética Química Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86794852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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