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Ecletica Quimica最新文献

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Construção de um calorímetro de baixo custo para a determinação de entalpia de neutralização 用于测定中和焓的低成本量热计的构建
Ecletica Quimica Pub Date : 2018-01-16 DOI: 10.1590/S0100-46702010000200007
M. Assumpcao, Luciani Wolf, Viviane Gomes Bonifácio, O. Fatibello-Filho
{"title":"Construção de um calorímetro de baixo custo para a determinação de entalpia de neutralização","authors":"M. Assumpcao, Luciani Wolf, Viviane Gomes Bonifácio, O. Fatibello-Filho","doi":"10.1590/S0100-46702010000200007","DOIUrl":"https://doi.org/10.1590/S0100-46702010000200007","url":null,"abstract":"In this article the construction of a simple calorimeter (with easily acquired materials) for the determination of the enthalpy of neutralization at constant pressure of acid-base reactions is described. Solutions of weak and strong acids and bases, one thermometer, and one expanded-polystyrene (Styrofoam) container were used in the development of the experiment. With this calorimeter, it was possible to determine the enthalpy of neutralization of reactions and compare the obtained values with the most accepted one of - 55.84 kJ mol-1, at 25 ° C [1].","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1590/S0100-46702010000200007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47263271","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}
引用次数: 2
Production of biodiesel from babassu oil using methanol-ethanol blends 利用甲醇-乙醇混合物从巴巴苏油生产生物柴油
Ecletica Quimica Pub Date : 2018-01-15 DOI: 10.1590/S0100-46702010000100006
F. Silva, K. B. Cavalcante, H. C. Louzeiro, Katia Regina Marques Moura, A. Maciel, L. E. B. Soledade, A. G. Souza
{"title":"Production of biodiesel from babassu oil using methanol-ethanol blends","authors":"F. Silva, K. B. Cavalcante, H. C. Louzeiro, Katia Regina Marques Moura, A. Maciel, L. E. B. Soledade, A. G. Souza","doi":"10.1590/S0100-46702010000100006","DOIUrl":"https://doi.org/10.1590/S0100-46702010000100006","url":null,"abstract":"Maranhao state in Brazil presents a big potential for the cultivation of several oleaginous species, such as babassu, soybean, castor oil plant, etc... These vegetable oils can be transformed into biodiesel by the transesterification reaction in an alkaline medium, using methanol or ethanol. The biodiesel production from a blend of these alcohols is a way of adding the technical and economical advantages of methanol to the environmental advantages of ethanol. The optimized alcohol blend was observed to be a methanol/ethanol volume ratio of 80 % MeOH: 20 % EtOH. The ester content was of 98.70 %, a value higher than the target of the ANP, 96.5 % (m/m), and the biodiesel mass yield was of 95.32 %. This biodiesel fulfills the specifications of moisture, specific gravity, kinematic viscosity and percentages of free alcohols (methanol plus ethanol) and free glycerin.","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1590/S0100-46702010000100006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49343584","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}
引用次数: 20
Mathematical equation correction to spectral and transport interferences in high-resolution continuum source flame atomic absorption spectrometry: determination of lead in phosphoric acid 高分辨率连续源火焰原子吸收光谱法中光谱和输运干扰的数学方程修正:磷酸中铅的测定
Ecletica Quimica Pub Date : 2018-01-15 DOI: 10.1590/S0100-46702010000100002
J. Raposo, S. R. Oliveira, J. Nóbrega, J. A. Neto
{"title":"Mathematical equation correction to spectral and transport interferences in high-resolution continuum source flame atomic absorption spectrometry: determination of lead in phosphoric acid","authors":"J. Raposo, S. R. Oliveira, J. Nóbrega, J. A. Neto","doi":"10.1590/S0100-46702010000100002","DOIUrl":"https://doi.org/10.1590/S0100-46702010000100002","url":null,"abstract":"In this work, a new mathematical equation correction approach for overcoming spectral and transport interferences was proposed. The proposal was applied to eliminate spectral interference caused by PO molecules at the 217.0005 nm Pb line, and the transport interference caused by variations in phosphoric acid concentrations. Correction may be necessary at 217.0005 nm to account for the contribution of PO, since Atotal217.0005 nm = A Pb217.0005 nm + A PO217.0005 nm. This may be easily done by measuring other PO wavelengths (e.g. 217.0458 nm) and calculating the relative contribution of PO absorbance (APO) to the total absorbance (Atotal) at 217.0005 nm: A Pb217.0005 nm = Atotal217.0005 nm - A PO217.0005 nm = Atotal217.0005 nm - k (A PO217.0458 nm). The correction factor k is calculated from slopes of calibration curves built up for phosphorous (P) standard solutions measured at 217.0005 and 217.0458 nm, i.e. k = (slope217.0005 nm/slope217.0458 nm). For wavelength integrated absorbance of 3 pixels, sample aspiration rate of 5.0 ml min-1, analytical curves in the 0.1 - 1.0 mg L-1 Pb range with linearity better than 0.9990 were consistently obtained. Calibration curves for P at 217.0005 and 217.0458 nm with linearity better than 0.998 were obtained. Relative standard deviations (RSD) of measurements (n = 12) in the range of 1.4 - 4.3% and 2.0 - 6.0% without and with mathematical equation correction approach were obtained respectively. The limit of detection calculated to analytical line at 217.0005 nm was 10 µg L-1 Pb. Recoveries for Pb spikes were in the 97.5 - 100% and 105 - 230% intervals with and without mathematical equation correction approach, respectively.","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44813207","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}
引用次数: 1
Optimization of a homogeneous ternary solvent system for the quantification of lead in crystal sugar samples 均匀三元溶剂体系测定冰糖样品中铅的优化
Ecletica Quimica Pub Date : 2017-12-30 DOI: 10.26850/1678-4618EQJ.V42.1.2017.P65-70
Júnior Olair Chagas, S. Corrêa, Isabela Cristina Silva Melo, F. Lobo, Alex Magalhães de Almeida
{"title":"Optimization of a homogeneous ternary solvent system for the quantification of lead in crystal sugar samples","authors":"Júnior Olair Chagas, S. Corrêa, Isabela Cristina Silva Melo, F. Lobo, Alex Magalhães de Almeida","doi":"10.26850/1678-4618EQJ.V42.1.2017.P65-70","DOIUrl":"https://doi.org/10.26850/1678-4618EQJ.V42.1.2017.P65-70","url":null,"abstract":"During sugar production, contamination of the sugar by potentially toxic metals may occur. Therefore, it is necessary to develop methods to quantify these contaminants. An analytical method for the monitoring of lead in sugar samples was developed with the use of homogeneous ternary system of solvents and UV-Vis spectrophotometry. The ternary system was optimized using multivariate experiments and the best condition was: 10% water, 80% ethanol and 10% methyl isobutyl ketone. As the complexing agent, monosodium 4- (2-pyridylazo) resorcinol was used. The calibration curve was linear from 0.64 to 5.0 mg.L -1 , ABS = 0.0873 [Pb 2 + ] - 0.0032 and R² = 0.9988. The limit of quantification was 0.53 mg.L -1 and limit of detection was 0.45 mg.L -1 with 95% confidence level, the standard addition curve was linear, ABS = 0.0736 [Pb 2+ ] + 0.0846 And R² = 0.9971. Three samples were analyzed in triplicate and the concentration of lead obtained ranged from 84,741 ± 3,700 mg.Kg-1; 69.926 ± 11.837 mg.Kg -1 and 76.444 ± 7.1111 mg.Kg -1 . For the standard addition curve, the concentration found was approximately 230,000 mg.kg -1 . Considering the Brazilian standard, the lead concentration should not exceed 2.00 mg.Kg -1 , thus, it is concluded that the values obtained were not within the norm for this metal.","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47335082","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}
引用次数: 0
SELEÇÃO DE VARIÁVEIS PARA CATEGORIZAÇÃO DE AMOSTRAS QUÍMICAS 化学样品分类的变量选择
Ecletica Quimica Pub Date : 2017-10-31 DOI: 10.26850/1678-4618EQJ.V36.4.2011.P28-33
M. J. Anzanello
{"title":"SELEÇÃO DE VARIÁVEIS PARA CATEGORIZAÇÃO DE AMOSTRAS QUÍMICAS","authors":"M. J. Anzanello","doi":"10.26850/1678-4618EQJ.V36.4.2011.P28-33","DOIUrl":"https://doi.org/10.26850/1678-4618EQJ.V36.4.2011.P28-33","url":null,"abstract":"This paper presents a method to select the best variables to categorize chemical samples into two classes, say conforming or non-conforming. For that matter...","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47881900","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}
引用次数: 0
A LIQUID CHROMATOGRAPHY METHOD FOR DETERMINATION OF PYRETHROIDS INSECTICIDES RESIDUES IN BEANS. 液相色谱法测定大豆中拟除虫菊酯类杀虫剂残留量。
Ecletica Quimica Pub Date : 2017-10-31 DOI: 10.26850/1678-4618EQJ.V36.4.2011.P14-20
S. H. Monteiro, C. H. P. Ciscato, A. B. Gebara, J. Masini
{"title":"A LIQUID CHROMATOGRAPHY METHOD FOR DETERMINATION OF PYRETHROIDS INSECTICIDES RESIDUES IN BEANS.","authors":"S. H. Monteiro, C. H. P. Ciscato, A. B. Gebara, J. Masini","doi":"10.26850/1678-4618EQJ.V36.4.2011.P14-20","DOIUrl":"https://doi.org/10.26850/1678-4618EQJ.V36.4.2011.P14-20","url":null,"abstract":"A rapid liquid chromatographic (LC) method was developed for simultaneous determination of 7 pyrethroid insecticides in beans. Residues were extracted ...","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47948556","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}
引用次数: 0
Transition Metal Complexes of Omeprazole An Anti-Ulcerative Drug 抗溃疡药物奥美拉唑的过渡金属配合物
Ecletica Quimica Pub Date : 2017-10-31 DOI: 10.26850/1678-4618EQJ.V36.3.2011.P31-36
S. Malik, Supriya Das, B. Jain
{"title":"Transition Metal Complexes of Omeprazole An Anti-Ulcerative Drug","authors":"S. Malik, Supriya Das, B. Jain","doi":"10.26850/1678-4618EQJ.V36.3.2011.P31-36","DOIUrl":"https://doi.org/10.26850/1678-4618EQJ.V36.3.2011.P31-36","url":null,"abstract":"Omeprazole (OME) is a proton pump inhibitor (PPI). PPI’s have enabled to improve the treatment of various acidpeptic disorders. OME is a weak base and it can...","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69144332","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}
引用次数: 1
Estudo da retenção de íons cromo por gibbsita e peneira molecular (Chrome retention study by gibbsite and molecular sieves) 三水石与分子筛对铬截留的研究
Ecletica Quimica Pub Date : 2017-10-31 DOI: 10.26850/1678-4618EQJ.V36.1.2011.P123-141
L. C. Soares, E. Souza, M. Yoshida
{"title":"Estudo da retenção de íons cromo por gibbsita e peneira molecular (Chrome retention study by gibbsite and molecular sieves)","authors":"L. C. Soares, E. Souza, M. Yoshida","doi":"10.26850/1678-4618EQJ.V36.1.2011.P123-141","DOIUrl":"https://doi.org/10.26850/1678-4618EQJ.V36.1.2011.P123-141","url":null,"abstract":"Neste trabalho, relatamos o emprego de gibbsita e de uma peneira molecular comercial para a retencao de ions cromo. Os estudos envolveram, alem destes materiais, solucoes com diferentes concentracoes do ion e variacoes na concentracao e na temperatura das solucoes e, tambem, do tempo de contato entre essas e as fases estacionarias. Os resultados desses experimentos e dos posteriores processos de lixiviacao do ion indicam que tanto a gibbsita quanto a peneira molecular sao materiais que apresentam alta capacidade de retencao deste ion e, alem disso, sao altamente resistentes aos processos de lixiviacao.","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41284028","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}
引用次数: 0
Conductometric determination of propranolol hydrochloride in pharmaceuticals 电导法测定药品中盐酸心得安的含量
Ecletica Quimica Pub Date : 2017-10-31 DOI: 10.1590/S0100-46702011000100008
E. R. Sartori, Nathália Vieira Barbosa, R. Faria, O. Fatibello‐Filho
{"title":"Conductometric determination of propranolol hydrochloride in pharmaceuticals","authors":"E. R. Sartori, Nathália Vieira Barbosa, R. Faria, O. Fatibello‐Filho","doi":"10.1590/S0100-46702011000100008","DOIUrl":"https://doi.org/10.1590/S0100-46702011000100008","url":null,"abstract":"In this paper the conductometric titration of propranolol hydrochloride in pharmaceutical formulations using silver nitrate as titrant is proposed. The method was based on the formation of an insoluble salt (AgCl(s)) between the chloride of propranolol hydrochloride molecule and Ag(I) ions of the titrant AgNO3. The effect of the PROP-AgNO3 concentrations and the interval of time between the successive additions of the titrant on the shape of the titration curve were studied. The obtained recoveries for four samples ranged from 96.8 to 105%. The proposed method was successfully applied in the determination of propranolol hydrochloride in several pharmaceutical formulations, with results in close agreement at a 95 % confidence level with those obtained using official spectrophotometric method.","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1590/S0100-46702011000100008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44162882","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}
引用次数: 9
OTIMIZAÇÃO DO PROCESSO FOTOCATALÍTICO HETEROGÊNEO PARA O TRATAMENTO DE PERCOLADO DE ATERRO SANITÁRIO 垃圾渗滤液处理多相光催化工艺的优化
Ecletica Quimica Pub Date : 2017-10-31 DOI: 10.26850/1678-4618EQJ.V36.3.2011.P01-07
Núbia Natália Brito, G. A. Brota, R. Pelegrini, José Euclídes Stipp Paterniani
{"title":"OTIMIZAÇÃO DO PROCESSO FOTOCATALÍTICO HETEROGÊNEO PARA O TRATAMENTO DE PERCOLADO DE ATERRO SANITÁRIO","authors":"Núbia Natália Brito, G. A. Brota, R. Pelegrini, José Euclídes Stipp Paterniani","doi":"10.26850/1678-4618EQJ.V36.3.2011.P01-07","DOIUrl":"https://doi.org/10.26850/1678-4618EQJ.V36.3.2011.P01-07","url":null,"abstract":"Eclética Química, 36 (3), 1-7, 2011. percolado é originário de aterros “velhos” por possuírem macromoléculas orgânicas resistentes à degradação microbiológica [1]. Pesquisas recentes têm apontado para o emprego de processos combinados, fazendo uso das vantagens de diferentes métodos. Os tratamentos químicos como, por exemplo, os POA podem ser utilizados em conjunto com tratamentos biológicos para aumentar a biodegradabilidade de compostos recalcitrantes, diminuindo o tempo de tratamento dos tradicionais processos biológicos [1].","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47505929","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}
引用次数: 1
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