Pub Date : 2017-01-01DOI: 10.15446/REV.COLOMB.QUIM.V46N1.62830
Fabián Amaya García, Maria Leonisa Sanchez Nuñez, Freddy A. Ramos, M. Puyana, I. Paixão, V. L. Teixeira, L. Castellanos
Los dolabellanos son diterpenos con importante actividad antiviral, la mayor parte de los estudios se han realizado con compuestos aislados de algas pardas del genero Dictyota. Los corales blandos son tambien una importante fuente de dolabellanos, pero el potencial antiviral de estos ha sido muy poco estudiado. Como parte de nuestra busqueda de compuestos bioactivos a partir de fuentes marinas, se llevo a cabo el estudio quimico de los dolabellanos presentes en los octocorales Eunicea laciniata y Eunicea asperula, recolectados en Santa Marta, Caribe colombiano. Los dolabellanos 1 - 6 fueron aislados del octocoral E. laciniata mientras que en E. asperula se encontraron los compuestos 2 , 4 y 5 . La elucidacion estructural se llevo a cabo mediante experimentos de RMN, espectrometria de masas, rotacion optica y posterior comparacion con reportes previos en la literatura. El analisis por CG-EM evidencio que la dolabellatrienona ( 2 ) se puede transformar en los compuestos 4 y 5 como producto del almacenamiento prolongado, no obstante, tales compuestos tambien estuvieron presentes en los extractos de los organismos estudiados. El compuesto 6 inhibio la replicacion del VHS-1 (73,7% de inhibicion en celulas infectadas a una concentracion de 50 μM) sin efecto citotoxico (CC50 = 959), mostrando una citotoxicidad similar al Aciclovir®, un control positivo, por lo cual se perfila como un candidato para la realizacion de estudios adicionales sobre el potencial de los dolabellanos como agentes antivirales.
{"title":"Dolabellane diterpenes from the Caribbean soft corals Eunicea laciniata and Eunicea asperula and determination of their anti HSV-1 activity","authors":"Fabián Amaya García, Maria Leonisa Sanchez Nuñez, Freddy A. Ramos, M. Puyana, I. Paixão, V. L. Teixeira, L. Castellanos","doi":"10.15446/REV.COLOMB.QUIM.V46N1.62830","DOIUrl":"https://doi.org/10.15446/REV.COLOMB.QUIM.V46N1.62830","url":null,"abstract":"Los dolabellanos son diterpenos con importante actividad antiviral, la mayor parte de los estudios se han realizado con compuestos aislados de algas pardas del genero Dictyota. Los corales blandos son tambien una importante fuente de dolabellanos, pero el potencial antiviral de estos ha sido muy poco estudiado. Como parte de nuestra busqueda de compuestos bioactivos a partir de fuentes marinas, se llevo a cabo el estudio quimico de los dolabellanos presentes en los octocorales Eunicea laciniata y Eunicea asperula, recolectados en Santa Marta, Caribe colombiano. Los dolabellanos 1 - 6 fueron aislados del octocoral E. laciniata mientras que en E. asperula se encontraron los compuestos 2 , 4 y 5 . La elucidacion estructural se llevo a cabo mediante experimentos de RMN, espectrometria de masas, rotacion optica y posterior comparacion con reportes previos en la literatura. El analisis por CG-EM evidencio que la dolabellatrienona ( 2 ) se puede transformar en los compuestos 4 y 5 como producto del almacenamiento prolongado, no obstante, tales compuestos tambien estuvieron presentes en los extractos de los organismos estudiados. El compuesto 6 inhibio la replicacion del VHS-1 (73,7% de inhibicion en celulas infectadas a una concentracion de 50 μM) sin efecto citotoxico (CC50 = 959), mostrando una citotoxicidad similar al Aciclovir®, un control positivo, por lo cual se perfila como un candidato para la realizacion de estudios adicionales sobre el potencial de los dolabellanos como agentes antivirales.","PeriodicalId":43662,"journal":{"name":"Revista Colombiana de Quimica","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67056124","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 : 2017-01-01DOI: 10.15446/REV.COLOMB.QUIM.V46N1.59578
R. Loto
Mild steel corrosion is responsible for economic and industrial losses due to accelerated deterioration. Synthesized derivatives of thiourea and phenolic aldehydes containing heteroatoms are capable of inhibiting corrosion by adsorption onto the steel through formation of strong bonds. Thus, the electrochemical corrosion inhibition properties of the combined admixture of 1,3-diphenyl-2-thiourea and 4-hydroxy-3-methoxybenzaldehyde on mild steel in 1 M H2SO4 and HCl acid media were studied through weight loss analysis, potentiodynamic polarization method, optical microscopy and IR spectroscopy. Results showed that the organic mixture effectively inhibited the corrosion of mild steel in both solutions with an optimal inhibition efficiency of 97.4% and 97.47% in H2SO4 from weight loss and potentiodynamic polarization test, while the corresponding values in HCl were 94.71% and 89.73% respectively. Thermodynamic calculations showed that the compound chemisorbed onto the steel surface blocking the diffusion of corrosive anions. Observations from micro-analytical images confirmed the effective inhibition property of the compound and its presence on the surface topography of the steel. Infrared spectra revealed the presence of the functional groups of the organic compound responsible for corrosion inhibition. The adsorption of the compound was deduced to obey the Langmuir, Frumkin and Freundlich adsorption isotherm.
低碳钢的腐蚀由于加速恶化而造成经济和工业损失。合成的含杂原子的硫脲和酚醛衍生物能够通过形成强键吸附在钢上来抑制腐蚀。因此，通过失重分析、动电位极化法、光学显微镜和红外光谱研究了1,3-二苯基-2-硫脲和4-羟基-3-甲氧基苯甲醛复合添加剂在1 M H2SO4和HCl酸介质中对低碳钢的电化学缓蚀性能。结果表明，有机混合物在两种溶液中均能有效抑制低碳钢的腐蚀，失重和动电位极化试验结果表明，有机混合物对H2SO4的最佳缓蚀率分别为97.4%和97.47%，对HCl的最佳缓蚀率分别为94.71%和89.73%。热力学计算表明，该化合物在钢表面发生化学吸附，阻止了腐蚀性阴离子的扩散。显微分析图像的观察证实了该化合物的有效抑制性能及其在钢表面形貌上的存在。红外光谱显示了有机化合物中具有缓蚀作用的官能团的存在。推导出化合物的吸附服从Langmuir, Frumkin和Freundlich吸附等温线。
{"title":"Corrosion inhibition studies of the combined admixture of 1, 3-diphenyl-2-thiourea and 4-hydroxy-3-methoxybenzaldehyde on mild steel in dilute acid media","authors":"R. Loto","doi":"10.15446/REV.COLOMB.QUIM.V46N1.59578","DOIUrl":"https://doi.org/10.15446/REV.COLOMB.QUIM.V46N1.59578","url":null,"abstract":"Mild steel corrosion is responsible for economic and industrial losses due to accelerated deterioration. Synthesized derivatives of thiourea and phenolic aldehydes containing heteroatoms are capable of inhibiting corrosion by adsorption onto the steel through formation of strong bonds. Thus, the electrochemical corrosion inhibition properties of the combined admixture of 1,3-diphenyl-2-thiourea and 4-hydroxy-3-methoxybenzaldehyde on mild steel in 1 M H2SO4 and HCl acid media were studied through weight loss analysis, potentiodynamic polarization method, optical microscopy and IR spectroscopy. Results showed that the organic mixture effectively inhibited the corrosion of mild steel in both solutions with an optimal inhibition efficiency of 97.4% and 97.47% in H2SO4 from weight loss and potentiodynamic polarization test, while the corresponding values in HCl were 94.71% and 89.73% respectively. Thermodynamic calculations showed that the compound chemisorbed onto the steel surface blocking the diffusion of corrosive anions. Observations from micro-analytical images confirmed the effective inhibition property of the compound and its presence on the surface topography of the steel. Infrared spectra revealed the presence of the functional groups of the organic compound responsible for corrosion inhibition. The adsorption of the compound was deduced to obey the Langmuir, Frumkin and Freundlich adsorption isotherm.","PeriodicalId":43662,"journal":{"name":"Revista Colombiana de Quimica","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67055893","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 : 2017-01-01DOI: 10.15446/REV.COLOMB.QUIM.V46N1.62849
Beatriz Restrepo Cortés, Ángela Liliana Londoño Franco, Juan Antonio Sánchez López
Se realizo un estudio descriptivo transversal empleando acido 6-6‘-ditiodinicotinico (DTNA) como indicador para calcular los valores de la actividad de colinesterasa plasmatica (AchP) y eritrocitaria (AchE) humana y estandarizarlos para ser utilizados como indicadores de riesgo laboral por exposicion a organofosforados y carbamatos en la poblacion de la zona cafetera de Colombia. Se eligio esta tecnica pues es una alternativa precisa, sencilla y economica: con pocos interferentes permite analizar AchP y AchE, no se tiene que corregir con hemoglobina; el DTNA es estable congelado o refrigerado y permite analizar muchas muestras en poco tiempo. Se evaluaron 819 muestras de agricultores. La AchE fue significativamente mayor en las personas menores de 45 anos y en personas no fumigadoras, la AchP fue mayor en los fumigadores; esto es un indicador de que la poblacion fumigadora se encuentra expuesta a organofosforados y carbamatos de forma prolongada. Se sugiere utilizar como valores maximos de referencia de la AchE y AchP 11378 U/L y 10354 U/L, respectivamente como indicadores de intervencion ocupacional.
{"title":"Valores de colinesterasa plasmática y eritrocitaria con ácido 6-6‘-ditiodinicotínico (DTNA) como indicador","authors":"Beatriz Restrepo Cortés, Ángela Liliana Londoño Franco, Juan Antonio Sánchez López","doi":"10.15446/REV.COLOMB.QUIM.V46N1.62849","DOIUrl":"https://doi.org/10.15446/REV.COLOMB.QUIM.V46N1.62849","url":null,"abstract":"Se realizo un estudio descriptivo transversal empleando acido 6-6‘-ditiodinicotinico (DTNA) como indicador para calcular los valores de la actividad de colinesterasa plasmatica (AchP) y eritrocitaria (AchE) humana y estandarizarlos para ser utilizados como indicadores de riesgo laboral por exposicion a organofosforados y carbamatos en la poblacion de la zona cafetera de Colombia. Se eligio esta tecnica pues es una alternativa precisa, sencilla y economica: con pocos interferentes permite analizar AchP y AchE, no se tiene que corregir con hemoglobina; el DTNA es estable congelado o refrigerado y permite analizar muchas muestras en poco tiempo. Se evaluaron 819 muestras de agricultores. La AchE fue significativamente mayor en las personas menores de 45 anos y en personas no fumigadoras, la AchP fue mayor en los fumigadores; esto es un indicador de que la poblacion fumigadora se encuentra expuesta a organofosforados y carbamatos de forma prolongada. Se sugiere utilizar como valores maximos de referencia de la AchE y AchP 11378 U/L y 10354 U/L, respectivamente como indicadores de intervencion ocupacional.","PeriodicalId":43662,"journal":{"name":"Revista Colombiana de Quimica","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67056464","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 : 2017-01-01DOI: 10.15446/REV.COLOMB.QUIM.V46N1.62831
José Carriazo Baños, V. Lara, Cristian Ochoa Puentes
Se describio la intervencion del mineral magnetita como catalizador o como soporte catalitico, un material inorganico con una estructura de espinela inversa (FeFe2O4), en el desarrollo de un numero importante de reacciones quimicas de interes cientifico, tecnologico y ambiental. Debido a la necesidad actual de generar procesos quimicos eficientes y favorables ambientalmente, la magnetita se ha convertido en un material promisorio en los contextos de la quimica verde, la quimica fina y la catalisis heterogenea. Este oxido de hierro se ha estudiado en diversas reacciones: catalizador masico, soporte catalitico de metales y de oxidos metalicos, nucleo de catalizadores tipo core-shell, o modificado mediante el anclaje de organocatalizadores y complejos metalicos. Se discute el desempeno catalitico de estos sistemas basados en magnetita, en reacciones de catalisis asimetrica, ambiental, acido-base, de oxido-reduccion, de sintesis multicomponente y de acoplamiento C-C. Particularmente, dichos catalizadores han mostrado enorme importancia en ciertas reacciones de tipo Sonogashira, Sonogashira–Hagihara, Mannich, Ullman, Knoevenagel, Suzuki-Miyaura y Fenton heterogenea, entre otras. Finalmente, se detallaron algunos usos tecnologicos de la magnetita en el contexto nacional (Colombia) y se intento localizar geograficamente los depositos importantes.
{"title":"Magnetita (Fe3O4): Una estructura inorgánica con múltiples aplicaciones en catálisis heterogénea","authors":"José Carriazo Baños, V. Lara, Cristian Ochoa Puentes","doi":"10.15446/REV.COLOMB.QUIM.V46N1.62831","DOIUrl":"https://doi.org/10.15446/REV.COLOMB.QUIM.V46N1.62831","url":null,"abstract":"Se describio la intervencion del mineral magnetita como catalizador o como soporte catalitico, un material inorganico con una estructura de espinela inversa (FeFe2O4), en el desarrollo de un numero importante de reacciones quimicas de interes cientifico, tecnologico y ambiental. Debido a la necesidad actual de generar procesos quimicos eficientes y favorables ambientalmente, la magnetita se ha convertido en un material promisorio en los contextos de la quimica verde, la quimica fina y la catalisis heterogenea. Este oxido de hierro se ha estudiado en diversas reacciones: catalizador masico, soporte catalitico de metales y de oxidos metalicos, nucleo de catalizadores tipo core-shell, o modificado mediante el anclaje de organocatalizadores y complejos metalicos. Se discute el desempeno catalitico de estos sistemas basados en magnetita, en reacciones de catalisis asimetrica, ambiental, acido-base, de oxido-reduccion, de sintesis multicomponente y de acoplamiento C-C. Particularmente, dichos catalizadores han mostrado enorme importancia en ciertas reacciones de tipo Sonogashira, Sonogashira–Hagihara, Mannich, Ullman, Knoevenagel, Suzuki-Miyaura y Fenton heterogenea, entre otras. Finalmente, se detallaron algunos usos tecnologicos de la magnetita en el contexto nacional (Colombia) y se intento localizar geograficamente los depositos importantes.","PeriodicalId":43662,"journal":{"name":"Revista Colombiana de Quimica","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.15446/REV.COLOMB.QUIM.V46N1.62831","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67055747","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 : 2016-09-01DOI: 10.15446/REV.COLOMB.QUIM.V45N3.57351
M. Varela, Gustavo Adolfo Gutiérrez Gómez, Manuel Noé Chaur Valencia
The molecular geometry of ( E )-4-dimethylamino-N′-[(pyridin-2-yl)methylidene- N]benzohydrazide (C 15 H 16 N 4 O) complexed with M 2+ (M=Zn, Cu, Ni, Fe, Mn, Ca and Co) ions were calculated, using density functional theory (B3LYP) with 6-31G(d, p) basis set. Vibrational frequencies were computed in order to verify the absence of imaginary vibrational frequencies, fact that confirms the global minimum in geometry optimization. Molecular geometry parameters (bond lengths and angles) for Cu 2+ and Zn 2+ complexes were compared with crystallographic data previously reported, showing good correlation. Binding energies for all complexes were computed at B3LYP/6-31G++(d, p) level of theory. These calculations indicate that Cu-L is the lowest favorable complex, Cu 2+ corresponds to the smallest cation on the present study. In the other hand, Ca-L, one of the less favorable complex, corresponds to the biggest cation analyzed in the present study. Molecular orbital analysis was carried out showing variations in energy differences between HOMO-LUMO values in function of the metallic ion employed.
{"title":"A DFT study on Dichloro{(E)-4-dimethylamino-N′-[(pyridin-2 yl)methylidene-κN]benzohydrazide-κO}M2+ (M=Zn, Cu, Ni and Co) complexes: Effect of the metal over association energy and complex geometry","authors":"M. Varela, Gustavo Adolfo Gutiérrez Gómez, Manuel Noé Chaur Valencia","doi":"10.15446/REV.COLOMB.QUIM.V45N3.57351","DOIUrl":"https://doi.org/10.15446/REV.COLOMB.QUIM.V45N3.57351","url":null,"abstract":"The molecular geometry of ( E )-4-dimethylamino-N′-[(pyridin-2-yl)methylidene- N]benzohydrazide (C 15 H 16 N 4 O) complexed with M 2+ (M=Zn, Cu, Ni, Fe, Mn, Ca and Co) ions were calculated, using density functional theory (B3LYP) with 6-31G(d, p) basis set. Vibrational frequencies were computed in order to verify the absence of imaginary vibrational frequencies, fact that confirms the global minimum in geometry optimization. Molecular geometry parameters (bond lengths and angles) for Cu 2+ and Zn 2+ complexes were compared with crystallographic data previously reported, showing good correlation. Binding energies for all complexes were computed at B3LYP/6-31G++(d, p) level of theory. These calculations indicate that Cu-L is the lowest favorable complex, Cu 2+ corresponds to the smallest cation on the present study. In the other hand, Ca-L, one of the less favorable complex, corresponds to the biggest cation analyzed in the present study. Molecular orbital analysis was carried out showing variations in energy differences between HOMO-LUMO values in function of the metallic ion employed.","PeriodicalId":43662,"journal":{"name":"Revista Colombiana de Quimica","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67055621","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 : 2016-09-01DOI: 10.15446/REV.COLOMB.QUIM.V45N3.61381
Edgardo Meza Fuentes, J. R. Ruiz, Adolfo A. Pájaro Payares
Las hidrotalcitas pueden ser usadas en areas como catalisis, medicina, quimica ambiental, entre otras. Dependiendo de los metales presentes, los solidos derivados de la calcinacion de hidrotalcitas tambien son usados debido a su caracter basico, efecto de memoria y alta area superficial especifica. En este estudio se evaluaron caracteristicas de hidrotalcitas a base de Cu-Zn-Al. Los analisis se realizaron usando AAS, DRX, FTIR, TGA y DSC. Se observo que, en los solidos con mayor cantidad de cobre, la banda del estiramiento O••H (M••OH, H••OH) se desplaza a valores mas bajos de numero de onda, debido a que la densidad electronica de los grupos OH se orienta hacia el centro metalico de cobre. En todos los solidos se observo la formacion de la fase hidrotalcita, y de la fase Cu(OH) 2 en los solidos con mayor contenido de cobre, lo que puede ser atribuido al efecto Jahn-Teller. Los resultados mostraron que los solidos con mayor contenido de cobre colapsan en temperaturas menores. En todas las muestras se observaron eventos como: descomposicion de la estructura HTLc, formacion de oxidos metalicos y descomposicion de carbonatos que quedaron ocluidos en los poros de los solidos debido al colapso de la estructura laminar.
{"title":"Síntesis y caracterización estructural de hidrotalcitas de Cu-Zn-Al","authors":"Edgardo Meza Fuentes, J. R. Ruiz, Adolfo A. Pájaro Payares","doi":"10.15446/REV.COLOMB.QUIM.V45N3.61381","DOIUrl":"https://doi.org/10.15446/REV.COLOMB.QUIM.V45N3.61381","url":null,"abstract":"Las hidrotalcitas pueden ser usadas en areas como catalisis, medicina, quimica ambiental, entre otras. Dependiendo de los metales presentes, los solidos derivados de la calcinacion de hidrotalcitas tambien son usados debido a su caracter basico, efecto de memoria y alta area superficial especifica. En este estudio se evaluaron caracteristicas de hidrotalcitas a base de Cu-Zn-Al. Los analisis se realizaron usando AAS, DRX, FTIR, TGA y DSC. Se observo que, en los solidos con mayor cantidad de cobre, la banda del estiramiento O••H (M••OH, H••OH) se desplaza a valores mas bajos de numero de onda, debido a que la densidad electronica de los grupos OH se orienta hacia el centro metalico de cobre. En todos los solidos se observo la formacion de la fase hidrotalcita, y de la fase Cu(OH) 2 en los solidos con mayor contenido de cobre, lo que puede ser atribuido al efecto Jahn-Teller. Los resultados mostraron que los solidos con mayor contenido de cobre colapsan en temperaturas menores. En todas las muestras se observaron eventos como: descomposicion de la estructura HTLc, formacion de oxidos metalicos y descomposicion de carbonatos que quedaron ocluidos en los poros de los solidos debido al colapso de la estructura laminar.","PeriodicalId":43662,"journal":{"name":"Revista Colombiana de Quimica","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.15446/REV.COLOMB.QUIM.V45N3.61381","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67055640","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 : 2016-09-01DOI: 10.15446/REV.COLOMB.QUIM.V45N3.58760
H. Al-Hakeim, K. M. Jasem, S. Moustafa
SiO 2 NPs as an inhibitor of pepsin enzyme for treatment of gastro-esophageal reflux disease (GERD) was used. Silicon dioxide nanoparticles (pepsin coated SiO 2 NPs) are among the safest nanoparticles that can be used inside the human body. The activity of pepsin before and after the addition of certain amounts of the NPs to the reaction mixture was measured spectrophotometrically. Furthermore, these experiments were repeated at different temperatures, different weights of NPs, and different ionic strengths. The kinetic aparameters (K m & V max ) of the pepsin catalyzed reactions were calculated from the Lineweaver-Burke plots. The results showed that there is a significant reduction of pepsin activity by SiO 2 NPs (V max of free pepsin = 4.82 U and V max of the immobilizedpepsin = 2.90 U). The results also indicated that the presence of ionic strength causes remarkable reduction of pepsin activity. It can be concluded the best condition for inhibition of pepsin activity is by using a combination of SiO 2 NPs and high concentration NaCl at 37 °C.
{"title":"Anti-pepsin activity of silicon dioxide nanoparticles","authors":"H. Al-Hakeim, K. M. Jasem, S. Moustafa","doi":"10.15446/REV.COLOMB.QUIM.V45N3.58760","DOIUrl":"https://doi.org/10.15446/REV.COLOMB.QUIM.V45N3.58760","url":null,"abstract":"SiO 2 NPs as an inhibitor of pepsin enzyme for treatment of gastro-esophageal reflux disease (GERD) was used. Silicon dioxide nanoparticles (pepsin coated SiO 2 NPs) are among the safest nanoparticles that can be used inside the human body. The activity of pepsin before and after the addition of certain amounts of the NPs to the reaction mixture was measured spectrophotometrically. Furthermore, these experiments were repeated at different temperatures, different weights of NPs, and different ionic strengths. The kinetic aparameters (K m & V max ) of the pepsin catalyzed reactions were calculated from the Lineweaver-Burke plots. The results showed that there is a significant reduction of pepsin activity by SiO 2 NPs (V max of free pepsin = 4.82 U and V max of the immobilizedpepsin = 2.90 U). The results also indicated that the presence of ionic strength causes remarkable reduction of pepsin activity. It can be concluded the best condition for inhibition of pepsin activity is by using a combination of SiO 2 NPs and high concentration NaCl at 37 °C.","PeriodicalId":43662,"journal":{"name":"Revista Colombiana de Quimica","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67056031","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}
Simultaneous Distillation-Solvent Extraction (SDE) and Headspace Solid Phase Micro-extraction (HS-SPME), coupled to Gas Chromatography-Mass Spectrometry (GC-MS), for the recovery of volatiles from lulo pulp ( Solanum quitoense ) were compared. A completely randomized SDE/GC-MS design was applied to establish differences between the areas obtained with different solvents, whereas a two-way HS-SPME/GC-MS indicated the most appropriate extraction conditions of volatiles, having the type of fiber and the adsorption temperature as factors. SDE/GC-MS mainly promoted the extraction of hydrocarbons, aldehydes, and esters; whereas esters and aldehydes had higher areas using HS-SPME/GC-MS. Furthermore, the variance analysis showed a significant interaction among the type of fiber, the adsorption temperature, and the functional groups
{"title":"Comparación entre métodos de extracción para la obtención de volátiles a partir de pulpa de lulo (Solanum quitoense)","authors":"Eduardo Javid Corpas Iguarán, Gonzalo Taborda Ocampo, Omar Alberto Tapasco Alzate, Aristófeles Ortiz","doi":"10.15446/REV.COLOMB.QUIM.V45N3.61359","DOIUrl":"https://doi.org/10.15446/REV.COLOMB.QUIM.V45N3.61359","url":null,"abstract":"Simultaneous Distillation-Solvent Extraction (SDE) and Headspace Solid Phase Micro-extraction (HS-SPME), coupled to Gas Chromatography-Mass Spectrometry (GC-MS), for the recovery of volatiles from lulo pulp ( Solanum quitoense ) were compared. A completely randomized SDE/GC-MS design was applied to establish differences between the areas obtained with different solvents, whereas a two-way HS-SPME/GC-MS indicated the most appropriate extraction conditions of volatiles, having the type of fiber and the adsorption temperature as factors. SDE/GC-MS mainly promoted the extraction of hydrocarbons, aldehydes, and esters; whereas esters and aldehydes had higher areas using HS-SPME/GC-MS. Furthermore, the variance analysis showed a significant interaction among the type of fiber, the adsorption temperature, and the functional groups","PeriodicalId":43662,"journal":{"name":"Revista Colombiana de Quimica","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67056097","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 : 2016-09-01DOI: 10.15446/REV.COLOMB.QUIM.V45N3.61408
M. A. Gordillo, F. Zuluaga, M. Chaur
The kinetic and thermodynamic selectivity of acylhydrazone formation in dynamic combinatorial libraries (DCL) is described. Competition reactions were generated from hydrazides: isoniazid, 4-nitro-benzohydrazide, 4-dimethylamino-benzohydrazide, and nicotinic hydrazide; as well as the aldehyde derivatives: benzaldehyde and 2-pyridine-carboxaldehyde. The obtained species and the distribution of the DCLs were monitored by 1 H-NMR spectroscopy finding that those acylhydrazones containing the 4-dimethylamino-benzohydrazide are both the kinetic and thermodynamic product of their respective libraries. Configurational and coordination dynamics for some of these libraries were also investigated. The obtained results allowed the study of the redistribution of components and the amplification of one or more products using light and metal ions as physical and chemical templates, respectively.
{"title":"Acylhydrazone-based dynamic combinatorial libraries: study of the thermodynamic/kinetic evolution, configurational and coordination dynamics","authors":"M. A. Gordillo, F. Zuluaga, M. Chaur","doi":"10.15446/REV.COLOMB.QUIM.V45N3.61408","DOIUrl":"https://doi.org/10.15446/REV.COLOMB.QUIM.V45N3.61408","url":null,"abstract":"The kinetic and thermodynamic selectivity of acylhydrazone formation in dynamic combinatorial libraries (DCL) is described. Competition reactions were generated from hydrazides: isoniazid, 4-nitro-benzohydrazide, 4-dimethylamino-benzohydrazide, and nicotinic hydrazide; as well as the aldehyde derivatives: benzaldehyde and 2-pyridine-carboxaldehyde. The obtained species and the distribution of the DCLs were monitored by 1 H-NMR spectroscopy finding that those acylhydrazones containing the 4-dimethylamino-benzohydrazide are both the kinetic and thermodynamic product of their respective libraries. Configurational and coordination dynamics for some of these libraries were also investigated. The obtained results allowed the study of the redistribution of components and the amplification of one or more products using light and metal ions as physical and chemical templates, respectively.","PeriodicalId":43662,"journal":{"name":"Revista Colombiana de Quimica","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.15446/REV.COLOMB.QUIM.V45N3.61408","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67055690","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 : 2016-09-01DOI: 10.15446/REV.COLOMB.QUIM.V45N3.58085
Oman Zuas, Muhammad Rizky Mulyana, H. Budiman
An accurate gas chromatography coupled to a flame ionization detector (GC-FID) method was validated for the simultaneous analysis of light hydrocarbons (C 2 -C 4 ) in their gas mixture. The validation parameters were evaluated based on the ISO/IEC 17025 definition including method selectivity, repeatability, accuracy, linearity, limit of detection (LOD), limit of quantitation (LOQ), and ruggedness. Under the optimum analytical conditions, the analysis of gas mixture revealed that each target component was well-separated with high selectivity property. The method was also found to be precise and accurate. The method linearity was found to be high with good correlation coefficient values (R 2 ≥ 0.999) for all target components. It can be concluded that the GC-FID developed method is reliable and suitable for determination of light C 2 -C 4 hydrocarbons (including ethylene, propane, propylene, isobutane, and n-butane) in their gas mixture. The validated method has successfully been applied to the estimation of hydrocarbons light C 2 -C 4 hydrocarbons in natural gas samples, showing high performance repeatability with relative standard deviation (RSD) less than 1.0% and good selectivity with no interference from other possible components could be observed.
{"title":"Analytical method validation of GC-FID for the simultaneous measurement of hydrocarbons (C2-C4) in their gas mixture","authors":"Oman Zuas, Muhammad Rizky Mulyana, H. Budiman","doi":"10.15446/REV.COLOMB.QUIM.V45N3.58085","DOIUrl":"https://doi.org/10.15446/REV.COLOMB.QUIM.V45N3.58085","url":null,"abstract":"An accurate gas chromatography coupled to a flame ionization detector (GC-FID) method was validated for the simultaneous analysis of light hydrocarbons (C 2 -C 4 ) in their gas mixture. The validation parameters were evaluated based on the ISO/IEC 17025 definition including method selectivity, repeatability, accuracy, linearity, limit of detection (LOD), limit of quantitation (LOQ), and ruggedness. Under the optimum analytical conditions, the analysis of gas mixture revealed that each target component was well-separated with high selectivity property. The method was also found to be precise and accurate. The method linearity was found to be high with good correlation coefficient values (R 2 ≥ 0.999) for all target components. It can be concluded that the GC-FID developed method is reliable and suitable for determination of light C 2 -C 4 hydrocarbons (including ethylene, propane, propylene, isobutane, and n-butane) in their gas mixture. The validated method has successfully been applied to the estimation of hydrocarbons light C 2 -C 4 hydrocarbons in natural gas samples, showing high performance repeatability with relative standard deviation (RSD) less than 1.0% and good selectivity with no interference from other possible components could be observed.","PeriodicalId":43662,"journal":{"name":"Revista Colombiana de Quimica","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67055958","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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