Información Investigador: Petit de Peña, Yaneira del Valle

Doctorado1523III - 2002; II - 2001155 - 2005; 115 - 2003; 65 - 20011. Análisis por inyección en flujo acoplado con técnicas atómicas. 2. Uso de nuevos materiales para la preconcentración de metales. 3. Desarrollo de metodología analítica para la determinación de especies de interés en química clínica. 4. Correlación entre el contenido de algunos elementos químicos y diferentes fases de enfermedades tropicales (Leishmaniasis).Junio de 2006+58 274 2401375Facultad de [email protected]

Determination of nickel in cereals and derivates by on line extraction and preconcentration with AAS detection

Se desarrolló una metodología analítica para la determinación de Níquel en cereales y harinas de maíz comerciales, mediante la formación de su quelato neutro con pirrolidin ditiocarbamato de amonio (APDC), su preconcentración en una columna empacada con zeolita tipo Y sódica (YNa) y su elución con metil isobutilcetona (MIBK). Para ello se empleo una celda de sólidos (CS), diseñada en el laboratorio para el tratamiento y la extracción del analito de la matriz de la muestra, como parte de una configuración de inyección en flujo (FIA), acoplada a espectroscopia de absorción atómica en llama (EAA) como sistema de detección. Bajo las condiciones óptimas se logró un factor de preconcentración de 85, comparado con la aspiración directa de las soluciones acuosas en el espectrómetro. El límite de detección (3s), el coeficiente de variación relativo (RSD%) y la zona lineal de calibración obtenidos fueron 0,72; 0,22 y (30-70) µg.l-1, respectivamente, para un volumen de muestra de 6 [email protected]@ula.vecuatrimestreAn analytical methodology for the determination of nickel traces in commercial solid samples of cereals and corn flour was developed. Nickel was on-line extracted from solid samples in a lab-made cell incorporated to a flow injection system (FIA). After the extraction, a neutral chelate between nickel and ammonium pyrrolidinedithiocarbamate (APDC) was adsorbed on a minicolumn packed with zeolite type YNa. Finally, the chelate was eluted with methyl isobutyl ketone (MIBK) for nickel detection in a flame atomic absorption spectrometer. Under the optical conditions a preconcentration factor of 85 was readily achieved related to the direct introduction of aqueous solutions into an atomic absorption spectrometer. The detection limit (3s), RSD% and linear calibration graphs were 0.72, 0.22 and (30-70) µg.l-1, respectively, for a sample volume of 6 ml

Determination of cobalt in urine samples with preconcentration on Linde type A calcic synthetic zeolite and detection by FIA-FAAS

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Comparative pharmacokinetic study of two pentavalent antimonial used in cutaneous leishmaniasis in Venezuela

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Tolerability and physical-chemical comparison between lots registered and no registered lots of antimony (Glucantime® and Ulamina) in the treatment of cutaneous Leishmaniasis.

Editorial. Emponzoñamiento por escorpiones, arañas, insectos y otros invertebrados.Envenomation by scorpions, spiders, insects and other invertebrates.Salinas, Pedro JoséComparación de tolerabilidad y fisico-química entre lotes de antimonial comercial y no comercializado (Glucantime® vs. Ulamina) en el tratamiento de la Leishmaniasis cutánea.Tolerability and physical-chemical comparison between lots registered and no registered lots of antimony (Glucantime® and Ulamina) in the treatment of cutaneous Leishmaniasis.Vásquez de Ricciardi, LauraScorza, José VicenteVicuña-Fernández, NelsonPetit de P., YaneiraLópez, SabrinaRojas Moreno, ElinaMorales, Carmen CeciliaBendezú, HerminiaScorza Dagert, JoséMiranda de Contreras, LeticiaMecanismos moleculares en la patogenia de los edemas del síndrome nefrótico. Una revisión.Molecular mechanisms in the pathogenesis of edema in nephrotic syndrome. A review.Rondón Nucete, MiguelGuerra de Rondón, Ana OfeliaRondón Guerra, Ana VerónicaManejo de espasticidad en miembros superiores con infiltraciones de fenol y toxina botulínica.Phenol and botulinum toxin infiltrations in the treatment of upper extremities spasticity.Sepúlveda Corzo, Ángel JavierSalinas, Pedro JoséMonzón de Briceño, YolandaCastillo Trujillo, David JoséNiveles séricos de cinc (Zn), hierro (Fe) y cobre (Cu) de preescolares que acuden a consulta en los ambulatorios urbanos tipo III de la Ciudad de Mérida.Serum levels of zinc (Zn), iron (Fe) and copper (Cu) of preschool children who attended the urban ambulatories type III at Mérida City (Mérida state).Silva Larralte, TaniaAlarcón Corredor, Oscar MarinoAlarcón Silva, Angel O.Ramírez de Fernández, MaríaD´Jesús A., IraimaMejia de Díaz, María ArnoldaFuncionalidad familiar, estrato socio-económico y red de apoyo social de los residentes de postgrado de la Facultad de Medicina de la Universidad de Los Andes. Mérida. Venezuela.Family functionality, socioeconomic level and social support network in graduate residents of the Faculty of Medicine, University of the Andes, Mérida, Venezuela.González, CarmenMejia de Díaz, María ArnoldaAngulo, LuísD`Avila, MaríaRelación entre estrato socio-económico y presencia de gastritis en adultos que acuden a consulta en el IAHULA. Mérida.Relationship between socioeconomical status and gastritis in adults consulting at the IAHULA Mérida.Ramírez, V.E.Alarcón Corredor, Oscar MarinoVillasmil, Luis M.Dávila de Arriaga, Ana J.Villarroel, A.Periodontitis agresiva causada por Porphyromonas gingivalis. Reporte de un caso.Aggressive periodontitis caused by Porphyromonas gingivales. Case report.Ruiz A., MelinaBurguera G., LilianaRodríguez M., Antonio JesúsEmponzoñamiento escorpiónico en pacientes atentidos en el Hospital de Santa Cruz de Mora, Mérida, Venezuela.Scorpion envenomation in patients attending the Hospital at Santa Cruz de Mora, Mérida, Venezuela.Salinas, Perla R.Salinas, Pedro José4 - [email protected]@[email protected]@ula.veNivel analíticosemestra

Optimum phase-behavior formulation of surfactant/oil/water systems for the determination of chromium in heavy crude oil and in bitumen-in-water emulsion

Optimum phase-behavior formulation of surfactant/oil/water systems for the determination of chromium in heavy crude oil and in bitumen-in-water emulsion. (Burguera, José L.; Ávila G., Rita M.; Pascu de Burguera, Marcela; Antón, Raquel E.; Salager, Jean Louis; Bracho P., Carlos L.; Burguera Pascu, Margarita; Burguera Pascu, Constantin R.; Brunetto, Rosario; Gallignani, Maximo A.; Petit de P., Yaneira) Abstract An "oil in water" formulation was optimized to determine chromium in heavy crude oil (HCO) and bitumen-in-water emulsion (Orimulsion-400®) samples by transversally heated electrothermal atomic absorption spectrometry (TH-ET AAS) using Zeeman effect background correction. The optimum proportion of the oil-water mixture ratio was 7:3 v/v (70 ml of oil as the internal phase) with a non-ionic surfactant concentration (lntan-l00) in the emulsion of 0.2% w/w. Chromium was determined in different crude oil samples after dilution of the emulsions 1:9 v/v with a 0.2°/, w/w solution of surfactant in order to further reduce the viscosity from 100 to 1.6 cP and at the same time to bring the concentration of chromium within the working range of the ET AAS technique. The calibration graph was linear from 1.7 to 100 gg Cr 1- t. The sensitivity was of 0.0069 s 1 µg- ', the characteristic mass (mo) was of 5.7 pg per 0.0044 s and the detection limit (36) was of 0.52 pg 1-'. The relative standard deviation of the method, evaluated by replicate analyses of three crude oil samples varied in all cases between 1.5 and 2.6%. Recovery studies were performed on four Venezuelan crude oils, and the average chromium recovery values varied between 95.9-104.8, 90.6-107.6, 95.6-104.0 and 98.8-103.9% for the Cerro Negro, Crudo Hamaca and Boscan crude oils and for the Orimulsion®-400, respectively. The results obtained in this work for the Cerro Negro, Crudo Hamaca and Boscan crude oils and for the Orimulsion('~-400 following the proposed procedure were of 0.448±0.008, 0.338±0.004 0.524±0.021 and 0.174±0.008 mg Cr 1-t, respectively, which were in good agreement with the values obtained by a tedious recommended standard procedure (respectively: 0.470±0.05, 0.335±0.080, 0.570±0.021 and 0.173±0.009 mg Cr 1-t). CC) 2003 Elsevier B.V. All rights reserved. Artículo publicado en: Talanta 61 (2003) [email protected]@[email protected]@[email protected]@[email protected] monográfic