Pub Date : 2018-01-22DOI: 10.26850/1678-4618eqj.v35.4.2010.p153-163
V. Sargentelli, Antonio Aparecido Pupim Ferreira
The development of nanoparticles has been intensively pursued because of their technological importance. The magnetic nanoparticulate materials exhibit a series of interesting properties between which are mentioned the electrical, optical, magnetic and chemical properties. Magnetic nanostructures can be used in microelectronic and in medicine as in: magnetic memory storage, magnetic transport of biochemical complexes, magnetic resonance imaging, among others. The magnetic properties of nanoparticles there are very sensitive to its size and form. In this direction, many efforts they have been carried through with the intention of to control the form and distribution of the size of the nanoparticles. In the last few decades nanoparticles constituted by iron oxides had been studied. However, more recently, the focus of the researches has come back to others transitions metals. Amongst these, the cobalt comes being investigated due to its high magnetic susceptibility. In this context, the present article has the aim of to presents and to effect a comparative analysis of the more significant synthetic ways utilized in the present moment to obtain cobalt nanoparticles.
{"title":"Magnetic nanoparticles: the cobalt","authors":"V. Sargentelli, Antonio Aparecido Pupim Ferreira","doi":"10.26850/1678-4618eqj.v35.4.2010.p153-163","DOIUrl":"https://doi.org/10.26850/1678-4618eqj.v35.4.2010.p153-163","url":null,"abstract":"The development of nanoparticles has been intensively pursued because of their technological importance. The magnetic nanoparticulate materials exhibit a series of interesting properties between which are mentioned the electrical, optical, magnetic and chemical properties. Magnetic nanostructures can be used in microelectronic and in medicine as in: magnetic memory storage, magnetic transport of biochemical complexes, magnetic resonance imaging, among others. The magnetic properties of nanoparticles there are very sensitive to its size and form. In this direction, many efforts they have been carried through with the intention of to control the form and distribution of the size of the nanoparticles. In the last few decades nanoparticles constituted by iron oxides had been studied. However, more recently, the focus of the researches has come back to others transitions metals. Amongst these, the cobalt comes being investigated due to its high magnetic susceptibility. In this context, the present article has the aim of to presents and to effect a comparative analysis of the more significant synthetic ways utilized in the present moment to obtain cobalt nanoparticles.","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":"35 1","pages":"153-163"},"PeriodicalIF":0.0,"publicationDate":"2018-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46742998","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 : 2018-01-22DOI: 10.1590/S0100-46702010000400010
T. A. Santos, D. Costa, Samuel Pita, F. Semaan
The combination of two low-cost classical procedures based on titrimetric techniques is presented for the determination of pyridoxine hydrochloride in pharmaceuticals samples. Initially some experiments were carried out aiming to determine both pKa1 and pKa2 values, being those compared to values of literature and theoretical procedures. Commercial samples containing pyridoxine hydrochloride were electrochemically analysed by exploiting their acid-base and precipitation reactions. Potentiometric titrations accomplished the reaction between the ionizable hydrogens present in pyridoxine hydrochloride, being NaOH used as titrant; while the conductimetric method was based on the chemical precipitation between the chloride of pyridoxine hydrochloride molecule and Ag+ ions from de silver nitrate, changing the conductivity of the solution. Both methods were applied to the same commercial samples leading to concordant results when compared by statistical tests (95 and 98% confidence levels). Recoveries ranging from 99.0 to 108.1% were observed, showing no significant interference on the results.
{"title":"Potentiometric and conductimetric studies of chemical equilibria for pyridoxine hydrochloride in aqueous solutions: simple experimental determination of pKa values and analytical applications to pharmaceutical analysis","authors":"T. A. Santos, D. Costa, Samuel Pita, F. Semaan","doi":"10.1590/S0100-46702010000400010","DOIUrl":"https://doi.org/10.1590/S0100-46702010000400010","url":null,"abstract":"The combination of two low-cost classical procedures based on titrimetric techniques is presented for the determination of pyridoxine hydrochloride in pharmaceuticals samples. Initially some experiments were carried out aiming to determine both pKa1 and pKa2 values, being those compared to values of literature and theoretical procedures. Commercial samples containing pyridoxine hydrochloride were electrochemically analysed by exploiting their acid-base and precipitation reactions. Potentiometric titrations accomplished the reaction between the ionizable hydrogens present in pyridoxine hydrochloride, being NaOH used as titrant; while the conductimetric method was based on the chemical precipitation between the chloride of pyridoxine hydrochloride molecule and Ag+ ions from de silver nitrate, changing the conductivity of the solution. Both methods were applied to the same commercial samples leading to concordant results when compared by statistical tests (95 and 98% confidence levels). Recoveries ranging from 99.0 to 108.1% were observed, showing no significant interference on the results.","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":"35 1","pages":"81-86"},"PeriodicalIF":0.0,"publicationDate":"2018-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67637907","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 : 2018-01-22DOI: 10.1590/S0100-46702010000400001
Cleber Antônio Lindino, Marcia Lina Mitsui, Rodolfo Ortiguara, Daiane Felin, M. Rosa, R. A. Bariccatti
This work was to investigate the process of degradation of the drug Prednisolone Sodium Phosphate (FSP) in oral solution dosage form through the degradation experiments, evaluating the parameters in accordance with Resolution 899/2003 ANVISA and the degradation process of the drug. The method by high performance liquid chromatography (HPLC) developed for the determination of the drug was validated to demonstrate its applicability as an indicator of stability, ensuring reliability. After the method be validated to study the degradation of the drug, it was shown that drastic conditions of oxidative stress (H2O2 30%) and temperature 60 ° C, the degradation of the drug is dependent on its concentration (first order kinetics). The results were satisfactory, showing that this method is suitable to investigate the formation of degradation products in oral dosage form solution.
{"title":"ESTUDO DE ESTABILIDADE DO FOSFATO DISSÓDICO DE PREDNISOLONA EM CONDIÇÕES DE ESTRESSE OXIDATIVO E TÉRMICO, EM FORMULAÇÃO ORAL","authors":"Cleber Antônio Lindino, Marcia Lina Mitsui, Rodolfo Ortiguara, Daiane Felin, M. Rosa, R. A. Bariccatti","doi":"10.1590/S0100-46702010000400001","DOIUrl":"https://doi.org/10.1590/S0100-46702010000400001","url":null,"abstract":"This work was to investigate the process of degradation of the drug Prednisolone Sodium Phosphate (FSP) in oral solution dosage form through the degradation experiments, evaluating the parameters in accordance with Resolution 899/2003 ANVISA and the degradation process of the drug. The method by high performance liquid chromatography (HPLC) developed for the determination of the drug was validated to demonstrate its applicability as an indicator of stability, ensuring reliability. After the method be validated to study the degradation of the drug, it was shown that drastic conditions of oxidative stress (H2O2 30%) and temperature 60 ° C, the degradation of the drug is dependent on its concentration (first order kinetics). The results were satisfactory, showing that this method is suitable to investigate the formation of degradation products in oral dosage form solution.","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":"35 1","pages":"9-15"},"PeriodicalIF":0.0,"publicationDate":"2018-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42297358","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 : 2018-01-22DOI: 10.1590/S0100-46702010000400012
J. R. Locatelli, C. T. Carvalho, F. Caires, M. Ionashiro
Solid-state Ln-L compounds, where Ln stands for heavy trivalent lanthanides (Tb-Lu) and L is malonate, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy, TG-FTIR system, elemental analysis and complexometry were used to characterize and to study the thermal behaviour of these compounds. The dehydration of the compounds begins at 303 K and the anhydrous compounds are stable up to 548 K. The results also provided information concerning the ligand's denticity, thermal behaviour and identification of some gaseous products evolved during the thermal decomposition of these compounds.
{"title":"Synthesis, characterization and thermal behaviour of heavy trivalent lanthanide malonates","authors":"J. R. Locatelli, C. T. Carvalho, F. Caires, M. Ionashiro","doi":"10.1590/S0100-46702010000400012","DOIUrl":"https://doi.org/10.1590/S0100-46702010000400012","url":null,"abstract":"Solid-state Ln-L compounds, where Ln stands for heavy trivalent lanthanides (Tb-Lu) and L is malonate, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy, TG-FTIR system, elemental analysis and complexometry were used to characterize and to study the thermal behaviour of these compounds. The dehydration of the compounds begins at 303 K and the anhydrous compounds are stable up to 548 K. The results also provided information concerning the ligand's denticity, thermal behaviour and identification of some gaseous products evolved during the thermal decomposition of these compounds.","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":"35 1","pages":"93-100"},"PeriodicalIF":0.0,"publicationDate":"2018-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43975082","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 : 2018-01-22DOI: 10.1590/S0100-46702010000400004
M. Marques, D. Russowsky, L. M. A. Fontoura
Abstract : .Dihydropyrimidinones, such as monastrol and analogues, are heterocycles with known antineoplastic activity. Conformational analysis represents an important preliminary step in structure-activity correlation studies. Herein we describe the conformational analysis of monastrol and analogues by AM1 semi-empirical and ab initio HF/6-31G* calculations. Four equilibrium geometries were found ( s-cis/ap, s-cis/sp, s-trans/ap and s-trans/sp) , and the important internal rotations were those of the ab-unsaturated carbonyl system and of the aryl group connected to the heterocycle Keywords: conformational analysis, dihydropyrimidinones, Biginelli compound, AM1, HF/6-31G* Referencias [1] C. O. Kappe, Eur. J. Med. Chem. 35(12) (2000) 1043. [2] B. Desai, D. Dallinger, C. O. Kappe, Tetrahedron 62 (2006) 4651. [3] C. O. Kappe, O. V. Shishkin, G. Uray, P. Verdino Tetrahedron 56 (2000) 1859. [4] D. Russowsky, R. F. S. Canto, S. A. A. Sanches, M. G. M. D´Oca, A.Fatima, R. A. Pilli, L. K. Kohn, M. A. Antonio, J. E. Carvalho, Bioorg. Chem. 34 (2006) 173. [5] E. L. Eliel, S.H. Wilen, Stereochemistry of Organic Compounds, Wiley, New York, 1994.[6] C.R. Rodrigues, Cadernos Tematicos Quim. Nova Esc. 3 (2001) 43.[7] C. O. Kappe, W . M. F Fabian, A. Semones, Tetrahedron 53 (1997) 2803. [8] M.J.S. Dewar , E.G. Zoebisch, E.F . Healy J.J.P Stewart, J. Am. Chem. Soc. 107(13) (1985) 3902. [9] Spartan´02 (1.0.1), Wavefunction: Irvine, 2002.[10] G. D. Smith, R. L. Jaffe, J. Phys. Chem. 100 (48) (1996) 18718.M. J. Hafezi, F. Sharif, Mol. Struct.: THEOCHEM 814(1-3) (2007) 43.
摘要:双氢嘧啶类化合物是一类已知具有抗肿瘤活性的杂环化合物，如单astrol及其类似物。构象分析是构效相关性研究的重要基础。本文采用AM1半经验和从头计算HF/6-31G*方法对单甾体醇及其类似物进行了构象分析。发现了4种平衡构型(s-顺式/ap、s-顺式/sp、s-反式/ap和s-反式/sp)，其中重要的内旋为ab-不饱和羰基体系和与杂环连接的芳基。关键词:构象分析，二氢嘧啶，Biginelli化合物，AM1, HF/6-31G*参考文献[1]C. O. Kappe, Eur。医学化学杂志，35(12)(2000)1043。[10]刘建军，刘建军，刘建军，刘建军，四面体62(2006):451。[10] C. O. Kappe, O. V. Shishkin, G. Uray, P. Verdino，四面体56(2000)1859。[10] D. Russowsky, R. F. S. Canto, S. A. A. Sanches, M. G. M. D. Oca, A. fatima, R. A. Pilli, L. K. Kohn, M. A. Antonio, J. E. Carvalho, Bioorg。化学，34(2006)173。[10]张晓明，张晓明，张晓明，有机化合物的立体化学，中国化学，1994C.R. Rodrigues, Cadernos Tematicos Quim。新星学报，3 (2001)43. bbb . 0c.o.卡普，W。M. F . Fabian, A. Semones，四面体53(1997)2803。[10]杜瓦，索比施，e.f.。希利·j·j·p·斯图尔特化学。Soc. 107(13)(1985) 3902。[9] Spartan´02(1.0.1)，波函数:吉林大学学报(自然科学版)，2002g.d.史密斯，r.l.贾菲，j.p yys。化学100 (48)(1996)18718.M。J. Hafezi, F. Sharif, Mol. Struct。[j] .物理学报(自然科学版)(2007)。
{"title":"Análise conformacional de compostos de Biginelli com atividade antineoplásica","authors":"M. Marques, D. Russowsky, L. M. A. Fontoura","doi":"10.1590/S0100-46702010000400004","DOIUrl":"https://doi.org/10.1590/S0100-46702010000400004","url":null,"abstract":"Abstract : .Dihydropyrimidinones, such as monastrol and analogues, are heterocycles with known antineoplastic activity. Conformational analysis represents an important preliminary step in structure-activity correlation studies. Herein we describe the conformational analysis of monastrol and analogues by AM1 semi-empirical and ab initio HF/6-31G* calculations. Four equilibrium geometries were found ( s-cis/ap, s-cis/sp, s-trans/ap and s-trans/sp) , and the important internal rotations were those of the ab-unsaturated carbonyl system and of the aryl group connected to the heterocycle Keywords: conformational analysis, dihydropyrimidinones, Biginelli compound, AM1, HF/6-31G* Referencias [1] C. O. Kappe, Eur. J. Med. Chem. 35(12) (2000) 1043. [2] B. Desai, D. Dallinger, C. O. Kappe, Tetrahedron 62 (2006) 4651. [3] C. O. Kappe, O. V. Shishkin, G. Uray, P. Verdino Tetrahedron 56 (2000) 1859. [4] D. Russowsky, R. F. S. Canto, S. A. A. Sanches, M. G. M. D´Oca, A.Fatima, R. A. Pilli, L. K. Kohn, M. A. Antonio, J. E. Carvalho, Bioorg. Chem. 34 (2006) 173. [5] E. L. Eliel, S.H. Wilen, Stereochemistry of Organic Compounds, Wiley, New York, 1994.[6] C.R. Rodrigues, Cadernos Tematicos Quim. Nova Esc. 3 (2001) 43.[7] C. O. Kappe, W . M. F Fabian, A. Semones, Tetrahedron 53 (1997) 2803. [8] M.J.S. Dewar , E.G. Zoebisch, E.F . Healy J.J.P Stewart, J. Am. Chem. Soc. 107(13) (1985) 3902. [9] Spartan´02 (1.0.1), Wavefunction: Irvine, 2002.[10] G. D. Smith, R. L. Jaffe, J. Phys. Chem. 100 (48) (1996) 18718.M. J. Hafezi, F. Sharif, Mol. Struct.: THEOCHEM 814(1-3) (2007) 43.","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":"35 1","pages":"33-38"},"PeriodicalIF":0.0,"publicationDate":"2018-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48508838","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 : 2018-01-22DOI: 10.1590/S0100-46702010000400016
M. C. Santos, J. O. Tognolli, O. Oliveira
Peroxidases enzymes are heme-proteins found in the different organisms livings creature, especially vegetal, present in important physiological paper/biochemist as protection against microorganisms. The soy, one of the most important products for the Brazilian agribusiness, presents in the rind of its seeds (by-product) where has high activity of peroxidase, called soybean peroxidase, with potential of use in clinical analytical methods. The proposal of the work was to apply the factorial planning for optimization of the conditions extraction of this enzyme, definition of the conditions of kinetic-enzyme assay conditions (pH and temperature), using methodology of reply surface. The data obtained: i) extraction in cetonico power, ii) reactional medium: pH 3,3, volume of the sample contend enzyme 330 µL - 340 µL, hydrogen peroxide 4,2 mmol.L-1 150 µL, time of reaction 20 seconds, temperature 50o C, substrate guaiacol 30mmol.L-1 300 µL, and 0.1 mol.L-1 of NaCl. This chemometric methodology used to definition of the extraction conditions and parameters kinetic assay of soybean peroxidase was very efficient, compared the classical methodology of variations/repetitions (attempt and error).
{"title":"Quimiometria como ferramenta analitica para definição das condiçoes de ensaio da enzima peroxidase de soja","authors":"M. C. Santos, J. O. Tognolli, O. Oliveira","doi":"10.1590/S0100-46702010000400016","DOIUrl":"https://doi.org/10.1590/S0100-46702010000400016","url":null,"abstract":"Peroxidases enzymes are heme-proteins found in the different organisms livings creature, especially vegetal, present in important physiological paper/biochemist as protection against microorganisms. The soy, one of the most important products for the Brazilian agribusiness, presents in the rind of its seeds (by-product) where has high activity of peroxidase, called soybean peroxidase, with potential of use in clinical analytical methods. The proposal of the work was to apply the factorial planning for optimization of the conditions extraction of this enzyme, definition of the conditions of kinetic-enzyme assay conditions (pH and temperature), using methodology of reply surface. The data obtained: i) extraction in cetonico power, ii) reactional medium: pH 3,3, volume of the sample contend enzyme 330 µL - 340 µL, hydrogen peroxide 4,2 mmol.L-1 150 µL, time of reaction 20 seconds, temperature 50o C, substrate guaiacol 30mmol.L-1 300 µL, and 0.1 mol.L-1 of NaCl. This chemometric methodology used to definition of the extraction conditions and parameters kinetic assay of soybean peroxidase was very efficient, compared the classical methodology of variations/repetitions (attempt and error).","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":"35 1","pages":"121-131"},"PeriodicalIF":0.0,"publicationDate":"2018-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48379135","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 : 2018-01-22DOI: 10.1590/S0100-46702010000400014
D. Santos, D. Vieira
The purpose of this study was to determine the coefficient of thermal expansion of the biodiesel from the experimental data of density as a function of temperature. For this, we used some fundamentals of thermodynamics. The value obtained for the coefficient of thermal expansion after the linear regression for biodiesel was 8.49 × 10-4 ° C-1, with a correlation coefficient equal to 0.9978.
{"title":"Determinação de coeficiente de expansão térmica do biodiesel e seus impactos no sistema de medição volumétrico","authors":"D. Santos, D. Vieira","doi":"10.1590/S0100-46702010000400014","DOIUrl":"https://doi.org/10.1590/S0100-46702010000400014","url":null,"abstract":"The purpose of this study was to determine the coefficient of thermal expansion of the biodiesel from the experimental data of density as a function of temperature. For this, we used some fundamentals of thermodynamics. The value obtained for the coefficient of thermal expansion after the linear regression for biodiesel was 8.49 × 10-4 ° C-1, with a correlation coefficient equal to 0.9978.","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":"35 1","pages":"107-112"},"PeriodicalIF":0.0,"publicationDate":"2018-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44755120","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 : 2018-01-16DOI: 10.1590/S0100-46702010000200005
A. C. C. Bernardi, S. Oka, G. Souza
The improvement of analytical methods makes the search for new technologies fast, accurate and low cost are constantly being reviewed and evaluated. The main objective of this research was to compare three forms of extraction of potassium (nitro-perchloric decomposition, extraction with water and extraction with diluted solution of HCl) of plant tissues samples of Tanzania grass (Panicum maximum cv. Tanzania) and alfalfa (Medicago sativa cv. Crioula). The methods of K extraction of Tanzania grass and alfalfa plant tissue samples in acid solution or diluted with water were equivalent to the traditional method of nitro-perchloric decomposition and can replace it.
分析方法的改进使得对新技术的快速、准确和低成本的搜索不断受到审查和评估。本研究的主要目的是比较坦桑尼亚草（Panicum maximum cv.Tanzania）和苜蓿（Medicago sativa cv.Crioula）植物组织样品中钾的三种提取形式（硝基-高氯酸分解、用水提取和盐酸稀释溶液提取）。坦桑尼亚草和苜蓿植物组织样品在酸性溶液中或用水稀释提取K的方法与传统的硝基-高氯酸分解方法相当，可以取代它。
{"title":"Comparação de técnicas analíticas para a extração de potássio de amostras de tecido vegetal com água e soluções ácidas concentrada e diluída","authors":"A. C. C. Bernardi, S. Oka, G. Souza","doi":"10.1590/S0100-46702010000200005","DOIUrl":"https://doi.org/10.1590/S0100-46702010000200005","url":null,"abstract":"The improvement of analytical methods makes the search for new technologies fast, accurate and low cost are constantly being reviewed and evaluated. The main objective of this research was to compare three forms of extraction of potassium (nitro-perchloric decomposition, extraction with water and extraction with diluted solution of HCl) of plant tissues samples of Tanzania grass (Panicum maximum cv. Tanzania) and alfalfa (Medicago sativa cv. Crioula). The methods of K extraction of Tanzania grass and alfalfa plant tissue samples in acid solution or diluted with water were equivalent to the traditional method of nitro-perchloric decomposition and can replace it.","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":"35 1","pages":"45-49"},"PeriodicalIF":0.0,"publicationDate":"2018-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45239900","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 : 2018-01-16DOI: 10.1590/S0100-46702010000200002
S. Sargenti, C. A. Almeida
The goal of this work was to develop a simple and rapid preparation method for pa- tulin analysis in apple juice without previous clean-up. This method combined sonication and liquid extraction techniques and was used for determination of patulin in 37 commercial apple juices available on the market in the South of Brazil. The method performance characteristics were determined using a sample obtained in a local market fortified at five concentration levels of patulin and done in triplicates. The coefficient of variation for repeatability at the fortifica- tion level of 20.70µg.L -1 was 3.53 % and the recovery 94.63 %, respectively. The correlation coefficient was 0.9996 and agrees with the requirements for a linear analytical method value. The detection limit was 0.21µg.L -1 and the quantification limit 0.70 µg.L -1 . Only three of the analyzed samples were upper the allowed level of 50.00 µg.L -1 recommended for the World
{"title":"Determination of patulin in apple juice by HPLC using a simple and fast sample preparation method","authors":"S. Sargenti, C. A. Almeida","doi":"10.1590/S0100-46702010000200002","DOIUrl":"https://doi.org/10.1590/S0100-46702010000200002","url":null,"abstract":"The goal of this work was to develop a simple and rapid preparation method for pa- tulin analysis in apple juice without previous clean-up. This method combined sonication and liquid extraction techniques and was used for determination of patulin in 37 commercial apple juices available on the market in the South of Brazil. The method performance characteristics were determined using a sample obtained in a local market fortified at five concentration levels of patulin and done in triplicates. The coefficient of variation for repeatability at the fortifica- tion level of 20.70µg.L -1 was 3.53 % and the recovery 94.63 %, respectively. The correlation coefficient was 0.9996 and agrees with the requirements for a linear analytical method value. The detection limit was 0.21µg.L -1 and the quantification limit 0.70 µg.L -1 . Only three of the analyzed samples were upper the allowed level of 50.00 µg.L -1 recommended for the World","PeriodicalId":35894,"journal":{"name":"Ecletica Quimica","volume":"35 1","pages":"15-21"},"PeriodicalIF":0.0,"publicationDate":"2018-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48524037","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 : 2018-01-16DOI: 10.1590/S0100-46702010000200008
I. Soares, T. Rezende, I. Fortes
The aim of this present work was to provide a more fast, simple and less expensive to analyze sulfur content in diesel samples than by the standard methods currently used. Thus, samples of diesel fuel with sulfur concentrations varying from 400 and 2500 mgkg-1 were analyzed by two methodologies: X-ray fluorescence, according to ASTM D4294 and by Fourier transform infrared spectrometry (FTIR). The spectral data obtained from FTIR were used to build multivariate calibration models by partial least squares (PLS). Four models were built in three different ways: 1) a model using the full spectra (665 to 4000 cm-1), 2) two models using some specific spectrum regions and 3) a model with variable selected by classic method of variable selection stepwise. The model obtained by variable selection stepwise and the model built with region spectra between 665 and 856 cm-1 and 1145 and 2717 cm-1 showed better results in the determination of sulfur content.
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