Browsing by Author "Toral Ponce, María"
Now showing items 1-20 of 32
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González Navarrete, Javier; Toral Ponce, María; Leiva, Angel; Yazdani-Pedram Zobeiri, Mehrdad; Ríos, Hernán; Briones-Olarán, Ximena; Urzúa Acevedo, Marcela (Elsevier B.V., 2016)Adsorption of As (V) by poly (N-octyl-4-vinylpyridinium) bromide (P4VPyC8), used as solid phase, was studied. Determination of As (V) was carried out by direct measurement of the fluorescence intensity on the solid phase. ...
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Narváez, Jessica; Richter Duk, Pablo; Toral Ponce, María (SPRINGER HEIDELBERG, 2005-04)A simple continuous flow method is proposed to eliminate copper interference in arsenic speciation by hydride generation, based on the selective retention of this interfering ion in an iminodiacetate chelating resin previous ...
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Richter Duk, Pablo; Toral Ponce, María; Tapia, A. Eugenia; Ubilla, Claudia; Bunster, Mauricio (Sociedad Chilena de Química, 1996)Se propone un método de análisis por inyección en flujo (FIA) con flujo interrumpido para la determinación simultánea de cobre y zinc. El método se basa en las diferentes velocidades en que se produce la reacción entre ...
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Toral Ponce, María; Hernández, Paola; Richter Duk, Pablo (MARCEL DEKKER INC, 1996)A continuous flow injection reaction-stopped flow detection method using derivative spectrophotometry was developed for the determination of cobalt and iron in mixtures. A conventional two-channel flow injection manifold ...
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Bustamante Araya, Ramiro; Toral Ponce, María; Richter Duk, Pablo; Serey Estay, Italo; Yates, L. R. (KLUWER ACADEMIC PUBL, 1997-05)Copper mining activities are very important in central Chile. Like other metals, copper is a nutrient for most plants at low concentration levels; however, at higher levels it may become toxic. At present, copper abundance ...
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Toral Ponce, María; Lara, Nelson; Gomez, Javier; Richter Duk, Pablo (Sociedad Chilena de Quimica, 2001)A microdetermination of iron at sub-μg/L level by derivative spectrophotometry has been developed. The compound TPTZ (2, 4, 6-tripyridyl-1, 3, 5-triazine) was used as chromogenic reagent to form a blue complex (pH = 5. 0), ...
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Toral Ponce, María; Paine, Maximiliano; Leyton, Patricio; Richter Duk, Pablo (AOAC INTERNATIONAL, 2004-11)A new method for the sequential determination of attapulgite and nifuroxazide in pharmaceutical formulations by first- and second-derivative spectrophotometry, respectively, has been developed. In order to obtain the optimal ...
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Segura, Rodrigo; Toral Ponce, María; Arancibia, Verónica (ELSEVIER SCIENCE BV, 2008-05-30)An adsorptive stripping voltammetry method for the determination of iron has been developed. The procedure is based on the adsorptive collection of a complex of iron with 1-(2-piridylazo)-2-naphthol (PAN) on a bismuth-coated ...
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Toral Ponce, María; Manríquez, Roberto; Richter Duk, Pablo (MARCEL DEKKER INC, 1999)A simple flow injection photometric method for the determination of copper was developed based on the formation and liquid-liquid extraction of the analyte-bathocuproine-perchlorate ternary complex. The analytical reaction ...
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Richter Duk, Pablo; Toral Ponce, María; Jaque, Pablo (WILEY-V C H VERLAG GMBH, 2000-03)The analytical application of a simple polarographic Row through cell, which was previously designed for the continuous polarographic analysis of organic compounds in pharmaceuticals and urine, is proposed in this work for ...
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Toral Ponce, María; Richter Duk, Pablo (ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS, 1996-05)An integrated retention/photometric detection method for the determination of microamounts of iron was developed. The method is based on the retention of the reaction product of the analyte with ferrozine in a flow cell ...
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Richter Duk, Pablo; Toral Ponce, María; Quiroz, Gabriela; Jaque, Pablo (JOHN WILEY & SONS INC, 1997)A simple design of a polarographic flow-through cell is proposed in which a conventional dropping mercury electrode (DME) is used as working electrode, and a mercury pool and a platinum wire are used as the reference and ...
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Richter Duk, Pablo; Toral Ponce, María; Parra Ortíz, María Valentina; Fuentes, Sandra; Araya, Eyleen (Sociedad Chilena de Química, 1995)Se desarrolla un método automático de análisis por inyección en flujo (FIA) para la determinación simultánea de hierro y titanio en mezclas. El método se basa en el diseño de una configuración FIA que incluye la reducción ...
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Polarographic behaviour and determination of nitrofurantoin, chloramphenicol and related compounds Morales, Alfonso; Toral Ponce, María; Richter Duk, Pablo (1984)The polarographic behaviour of nitrofurantoin and chloramphenicol have been studied in pyridine - formic acid buffer and tetramethylammonium chloride solution at pH 4.3. The E<inf>1/2</inf> versus pH and iym ...
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Richter Duk, Pablo; Toral Ponce, María; Muñoz-Vargas, Fernando (1994)A polarographic method for the determination of ranitidine is described, based on the reduction of the nitro group at a dropping-mercury electrode. The proposed method permits the drug to be determined, without any prior ...
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Carrera, M. Eugenia; Momberg, Astrid; Toral Ponce, María; Richter Duk, Pablo (1991)A preconcentration method based on the adsorption on activated carbon of a binary complex of copper(I) with 2,2’-biquinoline, and subsequent polarographic determination of microamounts of copper has been developed. The ...
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Morales, A.; Richter Duk, Pablo; Toral Ponce, María (Royal Society of Chemistry, 1987)In pyridine - formic acid buffer and tetramethylammonium chloride solution over the pH range 0-8.5, nitrofurazone, furazolidone and other nitrofuran derivatives are reduced in a six-electron process, giving rise to a well ...
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Narváez, Jessica; Richter Duk, Pablo; Toral Ponce, María (SOC CHILENA QUIMICA, 2007-09)The concentration of trace elements and other analytes of environmental interest was determined in waters and sediments of the Coya and Cachapoal rivers (VI Region, Central Chile), which corresponds to a location highly ...
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Toral Ponce, María; Pope, Stefanie; Quintanilla, Silvia; Richter Duk, Pablo (ELSEVIER SCIENCE BV, 2002-12-05)This work presents a simple and fast method for the simultaneous determination of amiloride and furosemide by digital derivative spectrophotometry. HCl 1 x 10(-2) mol/l dissolved in ethanol was used as solvent and to extract ...
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Simultaneous determination of ascorbic acid and acetylsalicylic acid in pharmaceutical formulations Toral Ponce, María; Lara Henríquez, Nelson; Richter Duk, Pablo; Tassara, Andrés; Tapia, A. E.; Rodríguez, C. (AOAC INTERNATIONAL, 2001-02)A direct, simple, and practical first-derivative spectrophotometric method is described for simultaneous determination of ascorbic acid and acetylsalicylic acid. The effects of the solvent, excipients, and spectral variables ...