Introducción. El uso de las arcillas activadas mediante modificación química para la adsorción y ... more Introducción. El uso de las arcillas activadas mediante modificación química para la adsorción y remoción de analitos en diferentes matrices ha abierto una gran ventana en la investigación de las potencialidades que tienen estas en campos diferentes a los que se ya se han estudiado, debido a su excelente capacidad de intercambio catiónico y sus grandes propiedades fisicoquímicas. En este trabajo se estudia la aplicación de las arcillas naturales tipo montmorillonitas sódicas (Mt-Na) activadas mediante agentes funcionalizantes específicos. Objetivo. Activar una arcilla tipo Mt-Na y emplearla en el proceso de blanqueamiento de aceite de palma crudo, y para la remoción del colorante índigo carmín usado en la industria textil. Materiales y métodos. La arcilla fue provista por la compañía Bentominercol S.A.S. (Líbano-Tolima). El aceite crudo de palma fue adquirido en la planta palmicultora Oleodavila en la región de Tumaco (Nariño). Los reactivos químicos usados son de grado analítico. L...
In this study, a novel environmentally-friendly approach was developed to overcome certain limita... more In this study, a novel environmentally-friendly approach was developed to overcome certain limitations in the analysis of solid food samples. An experimental setup based on solid-phase microextraction apparatus coupled to a rotating disk device is proposed for the determination of polar and slightly-polar pesticides including carbofuran, molinate, atrazine, simazine and tebuconazole in rice samples. In this innovative procedure, a rice sample is inserted into the cavity of the rotating disk device which is then immersed in an aqueous solution followed by high-speed agitation. In this case, water is employed as a green solvent for leaching the analytes from the sample matrix. Simultaneously, a solid-phase microextraction fiber comprised of divinylbenzene/carboxen/polydimethylsiloxane (2 cm length and 50/30 μm film thickness) was immersed in the aqueous solution to extract the slightly polar analytes from the aqueous matrix with subsequent thermal desorption in the injector of a gas chromatograph-mass spectrometer instrument. The optimal extraction conditions were obtained using an extraction temperature of 80 °C for 40 min, with 125 mg of rice inserted in the rotating disk. Using the previously optimized extraction conditions, the analytical performance was satisfactory with correlation coefficients higher than 0.9881 for all analytes, limits of detection ranging from 0.46 to 5.9 ng g-1, limits of quantification from 1.5 to 19.7 ng g-1, relative recoveries from 76 to 109%, intra-day precision (n = 3) from 1.3 to 19%, and inter-day precision (n = 9) from 3.5 to 6.5%. The proposed method represents a promising alternative for the analysis of complex solid food samples using SPME, since the SPME fiber damage is substantially decreased when the contact with the solid matrix is avoided.
Los compuestos conocidos como trihalometanos, a saber: cloroformo, bromodiclorometano, dibromoclo... more Los compuestos conocidos como trihalometanos, a saber: cloroformo, bromodiclorometano, dibromoclorometano y bromoformo, se forman en las plantas de potabilización durante la cloración de aguas que contienen precursores orgánicos (generalmente sustancias húmicas). Estos subproductos de la desinfección son tóxicos y están asociados a efectos adversos en la salud humana, tales como, riesgos en la función reproductiva y riesgo de cáncer. Dado que las vías de exposición a trihalometanos,son de alta frecuencia,se hace indispensable una regulación respecto a los niveles máximos de concentración de estos compuestos en el agua para consumo humano. Para la determinación de los precursores orgánicos cuantificados como carbono orgánico total (COT)se emplea la técnica de análisis por combustión y detección por infrarrojo no dispersivo; por su parte, para la determinación de trihalometanos se emplea la cromatografía de gases con detector de captura de electrones. Dichas técnicas de análisis quími...
Actualmente se vienen desarrollando métodos miniaturizados y sin uso de disolvente de preparación... more Actualmente se vienen desarrollando métodos miniaturizados y sin uso de disolvente de preparación de muestras para el análisis de contaminantes tales como hidrocarburos aromáticos policiclicos PAHs y sus derivados nitrados y contaminantes emergentes (biocidas, subproductos de desinfección, productos farmacéuticos y de cuidado personal) en diversas muestras ambientales (líquenes, musgos, aguas, aguas residuales, lodos, adhesivos, cosméticos, simulantes alimentarios). El trabajo involucra la separación cromatográfica y la detección usando sistemas GC-MS y HPLC-UV y confirmación con detección tandem QTOF-cuadrupolo. Evaluando las posibles correlaciones entre la procedencia de las muestras y la concentración de polutantes mediante el uso de herramientas matemáticas y estadísticas y llevando a cabo diseños de experimentos para optimizar las respuestas.
The combustion analysis technique and non-dispersive infrared (NDIR) detection was validated for ... more The combustion analysis technique and non-dispersive infrared (NDIR) detection was validated for the determination of organic matter in water, quantified as total organic carbon (TOC). Previously, the elimination of inorganic carbon (IC) of the sample ...
This research focused on laboratory-scale neutralization of cyanide wastes from the Nueva Esparta... more This research focused on laboratory-scale neutralization of cyanide wastes from the Nueva Esparta mine in the municipality of Los Andes, Sotomayor (Nariño) with three commercial type neutralizers in different weight ratios (neutralizer grams / CN-free/total to be neutralized): hydrogen ...
A new sorbent material based on modified clay with ionic liquid immobilized into an agarose film ... more A new sorbent material based on modified clay with ionic liquid immobilized into an agarose film was developed as part of this study. It was applied to determine organochlorine pollutants, like disinfection byproducts, through headspace solid-phase microextraction-gas chromatography-electron capture detection (HS-SPME-GC-ECD). The disinfection byproducts determined in this study were used as model molecules because they were volatile compounds, with proven severe effects on human health. Their presence in aquatic environments is in trace concentrations (from pg L−1 to mg L−1). They are classified as emergent pollutants and their determination is a challenge for analytical chemists. The parameters which affected the extraction efficiency, i.e., number and distance between SPME discs, salt concentration, the temperature of extraction, extraction time, and desorption time, were optimized. A wide linear dynamic range of 10–1000 ng mL−1 and coefficients of determination better than 0.997...
... por instrumentación (cromatografía de gases, analizador de combustión) al igual que toda técn... more ... por instrumentación (cromatografía de gases, analizador de combustión) al igual que toda técnica analítica, debe validarse (Quattrochi, 1992), es ... la concentración de COD, dosis de cloro, pH, temperatura y tiempo de reacción (Engerholm y Amy, 1983 en ... Quattrocchi, OA 1992. ...
Esta investigacion evalua a escala de laboratorio el efecto de baja turbiedad del agua almacenada... more Esta investigacion evalua a escala de laboratorio el efecto de baja turbiedad del agua almacenada en el reservorio (80000 m3) que almacena agua decantada y que posteriormente alimenta las unidades de la planta de tratamiento de agua de Puerto Mallarino en la ciudad de Cali, cuando no sea posible la operacion del sistema de tratamiento con agua cruda. Las variables de control son: tipo y dosis de coagulante a diferentes valores de pH, evaluadas con el equipo de jar test. Los diagramas de coagulacion elaborados permitieron la identificacion de las zonas de maxima eficiencia de remocion de turbiedad y color. El estudio se desarrollo en tres fases: Fase I: se empleo agua decantada por la planta Puerto Mallarino al emplear los coagulantes habituales de trabajo, cloruro ferrico y sulfato de aluminio, estas dos muestras fueron almacenadas por separado, durante 40 dias en tanques de 1000 cm3. Fase II: se recogio agua decantada, sin ser de interes el coagulante que se habia empleado en la pl...
Bivalves and sediments were sampled from mangroves in the Pacific Coast of Colombia to evaluate t... more Bivalves and sediments were sampled from mangroves in the Pacific Coast of Colombia to evaluate the concentrations of the 16 polycyclic aromatic hydrocarbons (PAHs) prioritized by U.S.EPA. Mangroves are highly vulnerable to anthropogenic activities, such as oil spills, which affect sediments and the organisms that depend on that ecosystem. Twelve samples of mangrove and non-mangrove (sandy) sediments and 20 samples of Anadara tuberculosa from mangrove were collected in marine and estuarine areas. In sediments and A. tuberculosa, the highest concentration of Ʃ16PAHs was found in estuarine mangroves close to the Rosario River mouth, ranging from 171.4 to 564.0 ng g-1 and 31.0 to 169.0 ng g-1, respectively. For the bivalve, the concentrations showed less variability than sediment, with 25% and 20% of bivalve samples exceeding the limits established by the European Regulatory Commission and Ministry of Health and Social Protection of Colombia, respectively, which can cause effects on people's health. The PAHs isomeric ratios determined in sediments indicated that these compounds were originated mainly from petrogenic sources. The PAHs profile reveals the dominance of 3 and 4 rings PAHs in sediments and dominance of 4 rings PAHs in bivalves.
In this study, a high throughput approach to rotating-disk sorptive extraction (RDSE) using lamin... more In this study, a high throughput approach to rotating-disk sorptive extraction (RDSE) using laminar cork as extraction phase is demonstrated for the first time in the determination of 20 multiclass organic micro-pollutants including pesticides, PAHs and UV filters compounds from aqueous samples with gas chromatography mass spectrometry (GC-MS). The influencing parameters (desorption solvent, volume and time, extraction time and sample pH and ionic strength) were carefully optimized using multivariate designs. The optimal conditions were 10 min for extraction using 35 mL of water samples and a liquid desorption using 1 mL of MeOH:AcOEt (50:50% v/v) for 20 min. A low-cost apparatus that allows six extractions simultaneously, providing a high throughput of 5 min per sample turnaround times, considering the sample preparation step was used for the first time in this modified RDSE methodology. Satisfactory analytical performance was achieved with limits of detection (LOD) between 0.08 and 1.5 μg L-1 and limits of quantification (LOQ) between 0.3 and 4.8 μg L-1. The relative recoveries for the analytes were determined using river and lake water samples spiked at different concentrations and ranging from 80% to 119% for all analytes, with relative standard deviations (RSD) lower than 20%. The extraction efficiency obtained for the proposed configuration with laminar cork was significantly superior to powdered cork, demonstrating an interesting new configuration for new applications.
This work reports for the first time the use of laminar cork as a sorptive phase in a microextrac... more This work reports for the first time the use of laminar cork as a sorptive phase in a microextraction technique, rotating-disk sorptive extraction (RDSE). Typical hormones (estrone, estradiol, estriol and ethinyl estradiol) were selected as analyte models and extracted from wastewater samples on laminar cork with statistically equivalent extraction efficiency to that provided by Oasis HLB. The cork characterization was performed by confocal fluorescence microscopy (CLSM), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), allowing the identification of lignin, suberin and polysaccharides (cellulose and hemicellulose) as the main components of the cork. The best conditions for extraction were as follows: rotation velocity of the disk, 2000 rpm; extraction time, 45 min; and sample volume, 20 mL. The analytical features of the developed method show that calibration curves for all analytes have R2 values higher than 0.99. The absolute recoveries were higher than 63%, and the precision, expressed as relative standard deviation, ranged from 2 to 16%. The LOD and LOQ ranges were 3-19 and 10-62 ng L-1, respectively. The proposed method was applied to the analysis of wastewater, and the concentrations of hormones in a wastewater treatment plant in Santiago, Chile, ranged from
Journal of Environmental Chemical Engineering, 2018
Abstract A simple and efficient solvent-free method for the quantification of total polychlorinat... more Abstract A simple and efficient solvent-free method for the quantification of total polychlorinated biphenyls (PCBs) in solid waste matrices by gas chromatography-mass spectrometry is proposed. Solid waste matrices spiked with Aroclor 1242 and Aroclor 1254 were used in this study. In this new approach, the cavity of the rotating disk device is loaded with the solid waste sample and water is used as leaching solvent allowing desorption of the analytes. Concomitantly a solid phase microextraction fiber is directly immersed in the water to extract the analytes. In order to improve the extraction efficiency, parameters such as pre-equilibrium, extraction time, temperature, ionic strength and the presence of an organic solvent were optimized. The values obtained for limits of detection (LOD) and limits of quantification (LOQ) are suitable for the determination of total PCBs in solid wastes and, subsequently, the most appropriate destination for the disposal of the waste can be selected. The accuracy and precision of the method exhibited satisfactory results, providing relative recoveries of 80.2–96.0% for total PCBs (at three spiked levels) and the relative standard deviations were between 2.5% and 15.5%. These results showed that the proposed method is a promising alternative for the determination of PCBs in solid wastes.
Introducción. El uso de las arcillas activadas mediante modificación química para la adsorción y ... more Introducción. El uso de las arcillas activadas mediante modificación química para la adsorción y remoción de analitos en diferentes matrices ha abierto una gran ventana en la investigación de las potencialidades que tienen estas en campos diferentes a los que se ya se han estudiado, debido a su excelente capacidad de intercambio catiónico y sus grandes propiedades fisicoquímicas. En este trabajo se estudia la aplicación de las arcillas naturales tipo montmorillonitas sódicas (Mt-Na) activadas mediante agentes funcionalizantes específicos. Objetivo. Activar una arcilla tipo Mt-Na y emplearla en el proceso de blanqueamiento de aceite de palma crudo, y para la remoción del colorante índigo carmín usado en la industria textil. Materiales y métodos. La arcilla fue provista por la compañía Bentominercol S.A.S. (Líbano-Tolima). El aceite crudo de palma fue adquirido en la planta palmicultora Oleodavila en la región de Tumaco (Nariño). Los reactivos químicos usados son de grado analítico. L...
In this study, a novel environmentally-friendly approach was developed to overcome certain limita... more In this study, a novel environmentally-friendly approach was developed to overcome certain limitations in the analysis of solid food samples. An experimental setup based on solid-phase microextraction apparatus coupled to a rotating disk device is proposed for the determination of polar and slightly-polar pesticides including carbofuran, molinate, atrazine, simazine and tebuconazole in rice samples. In this innovative procedure, a rice sample is inserted into the cavity of the rotating disk device which is then immersed in an aqueous solution followed by high-speed agitation. In this case, water is employed as a green solvent for leaching the analytes from the sample matrix. Simultaneously, a solid-phase microextraction fiber comprised of divinylbenzene/carboxen/polydimethylsiloxane (2 cm length and 50/30 μm film thickness) was immersed in the aqueous solution to extract the slightly polar analytes from the aqueous matrix with subsequent thermal desorption in the injector of a gas chromatograph-mass spectrometer instrument. The optimal extraction conditions were obtained using an extraction temperature of 80 °C for 40 min, with 125 mg of rice inserted in the rotating disk. Using the previously optimized extraction conditions, the analytical performance was satisfactory with correlation coefficients higher than 0.9881 for all analytes, limits of detection ranging from 0.46 to 5.9 ng g-1, limits of quantification from 1.5 to 19.7 ng g-1, relative recoveries from 76 to 109%, intra-day precision (n = 3) from 1.3 to 19%, and inter-day precision (n = 9) from 3.5 to 6.5%. The proposed method represents a promising alternative for the analysis of complex solid food samples using SPME, since the SPME fiber damage is substantially decreased when the contact with the solid matrix is avoided.
Los compuestos conocidos como trihalometanos, a saber: cloroformo, bromodiclorometano, dibromoclo... more Los compuestos conocidos como trihalometanos, a saber: cloroformo, bromodiclorometano, dibromoclorometano y bromoformo, se forman en las plantas de potabilización durante la cloración de aguas que contienen precursores orgánicos (generalmente sustancias húmicas). Estos subproductos de la desinfección son tóxicos y están asociados a efectos adversos en la salud humana, tales como, riesgos en la función reproductiva y riesgo de cáncer. Dado que las vías de exposición a trihalometanos,son de alta frecuencia,se hace indispensable una regulación respecto a los niveles máximos de concentración de estos compuestos en el agua para consumo humano. Para la determinación de los precursores orgánicos cuantificados como carbono orgánico total (COT)se emplea la técnica de análisis por combustión y detección por infrarrojo no dispersivo; por su parte, para la determinación de trihalometanos se emplea la cromatografía de gases con detector de captura de electrones. Dichas técnicas de análisis quími...
Actualmente se vienen desarrollando métodos miniaturizados y sin uso de disolvente de preparación... more Actualmente se vienen desarrollando métodos miniaturizados y sin uso de disolvente de preparación de muestras para el análisis de contaminantes tales como hidrocarburos aromáticos policiclicos PAHs y sus derivados nitrados y contaminantes emergentes (biocidas, subproductos de desinfección, productos farmacéuticos y de cuidado personal) en diversas muestras ambientales (líquenes, musgos, aguas, aguas residuales, lodos, adhesivos, cosméticos, simulantes alimentarios). El trabajo involucra la separación cromatográfica y la detección usando sistemas GC-MS y HPLC-UV y confirmación con detección tandem QTOF-cuadrupolo. Evaluando las posibles correlaciones entre la procedencia de las muestras y la concentración de polutantes mediante el uso de herramientas matemáticas y estadísticas y llevando a cabo diseños de experimentos para optimizar las respuestas.
The combustion analysis technique and non-dispersive infrared (NDIR) detection was validated for ... more The combustion analysis technique and non-dispersive infrared (NDIR) detection was validated for the determination of organic matter in water, quantified as total organic carbon (TOC). Previously, the elimination of inorganic carbon (IC) of the sample ...
This research focused on laboratory-scale neutralization of cyanide wastes from the Nueva Esparta... more This research focused on laboratory-scale neutralization of cyanide wastes from the Nueva Esparta mine in the municipality of Los Andes, Sotomayor (Nariño) with three commercial type neutralizers in different weight ratios (neutralizer grams / CN-free/total to be neutralized): hydrogen ...
A new sorbent material based on modified clay with ionic liquid immobilized into an agarose film ... more A new sorbent material based on modified clay with ionic liquid immobilized into an agarose film was developed as part of this study. It was applied to determine organochlorine pollutants, like disinfection byproducts, through headspace solid-phase microextraction-gas chromatography-electron capture detection (HS-SPME-GC-ECD). The disinfection byproducts determined in this study were used as model molecules because they were volatile compounds, with proven severe effects on human health. Their presence in aquatic environments is in trace concentrations (from pg L−1 to mg L−1). They are classified as emergent pollutants and their determination is a challenge for analytical chemists. The parameters which affected the extraction efficiency, i.e., number and distance between SPME discs, salt concentration, the temperature of extraction, extraction time, and desorption time, were optimized. A wide linear dynamic range of 10–1000 ng mL−1 and coefficients of determination better than 0.997...
... por instrumentación (cromatografía de gases, analizador de combustión) al igual que toda técn... more ... por instrumentación (cromatografía de gases, analizador de combustión) al igual que toda técnica analítica, debe validarse (Quattrochi, 1992), es ... la concentración de COD, dosis de cloro, pH, temperatura y tiempo de reacción (Engerholm y Amy, 1983 en ... Quattrocchi, OA 1992. ...
Esta investigacion evalua a escala de laboratorio el efecto de baja turbiedad del agua almacenada... more Esta investigacion evalua a escala de laboratorio el efecto de baja turbiedad del agua almacenada en el reservorio (80000 m3) que almacena agua decantada y que posteriormente alimenta las unidades de la planta de tratamiento de agua de Puerto Mallarino en la ciudad de Cali, cuando no sea posible la operacion del sistema de tratamiento con agua cruda. Las variables de control son: tipo y dosis de coagulante a diferentes valores de pH, evaluadas con el equipo de jar test. Los diagramas de coagulacion elaborados permitieron la identificacion de las zonas de maxima eficiencia de remocion de turbiedad y color. El estudio se desarrollo en tres fases: Fase I: se empleo agua decantada por la planta Puerto Mallarino al emplear los coagulantes habituales de trabajo, cloruro ferrico y sulfato de aluminio, estas dos muestras fueron almacenadas por separado, durante 40 dias en tanques de 1000 cm3. Fase II: se recogio agua decantada, sin ser de interes el coagulante que se habia empleado en la pl...
Bivalves and sediments were sampled from mangroves in the Pacific Coast of Colombia to evaluate t... more Bivalves and sediments were sampled from mangroves in the Pacific Coast of Colombia to evaluate the concentrations of the 16 polycyclic aromatic hydrocarbons (PAHs) prioritized by U.S.EPA. Mangroves are highly vulnerable to anthropogenic activities, such as oil spills, which affect sediments and the organisms that depend on that ecosystem. Twelve samples of mangrove and non-mangrove (sandy) sediments and 20 samples of Anadara tuberculosa from mangrove were collected in marine and estuarine areas. In sediments and A. tuberculosa, the highest concentration of Ʃ16PAHs was found in estuarine mangroves close to the Rosario River mouth, ranging from 171.4 to 564.0 ng g-1 and 31.0 to 169.0 ng g-1, respectively. For the bivalve, the concentrations showed less variability than sediment, with 25% and 20% of bivalve samples exceeding the limits established by the European Regulatory Commission and Ministry of Health and Social Protection of Colombia, respectively, which can cause effects on people's health. The PAHs isomeric ratios determined in sediments indicated that these compounds were originated mainly from petrogenic sources. The PAHs profile reveals the dominance of 3 and 4 rings PAHs in sediments and dominance of 4 rings PAHs in bivalves.
In this study, a high throughput approach to rotating-disk sorptive extraction (RDSE) using lamin... more In this study, a high throughput approach to rotating-disk sorptive extraction (RDSE) using laminar cork as extraction phase is demonstrated for the first time in the determination of 20 multiclass organic micro-pollutants including pesticides, PAHs and UV filters compounds from aqueous samples with gas chromatography mass spectrometry (GC-MS). The influencing parameters (desorption solvent, volume and time, extraction time and sample pH and ionic strength) were carefully optimized using multivariate designs. The optimal conditions were 10 min for extraction using 35 mL of water samples and a liquid desorption using 1 mL of MeOH:AcOEt (50:50% v/v) for 20 min. A low-cost apparatus that allows six extractions simultaneously, providing a high throughput of 5 min per sample turnaround times, considering the sample preparation step was used for the first time in this modified RDSE methodology. Satisfactory analytical performance was achieved with limits of detection (LOD) between 0.08 and 1.5 μg L-1 and limits of quantification (LOQ) between 0.3 and 4.8 μg L-1. The relative recoveries for the analytes were determined using river and lake water samples spiked at different concentrations and ranging from 80% to 119% for all analytes, with relative standard deviations (RSD) lower than 20%. The extraction efficiency obtained for the proposed configuration with laminar cork was significantly superior to powdered cork, demonstrating an interesting new configuration for new applications.
This work reports for the first time the use of laminar cork as a sorptive phase in a microextrac... more This work reports for the first time the use of laminar cork as a sorptive phase in a microextraction technique, rotating-disk sorptive extraction (RDSE). Typical hormones (estrone, estradiol, estriol and ethinyl estradiol) were selected as analyte models and extracted from wastewater samples on laminar cork with statistically equivalent extraction efficiency to that provided by Oasis HLB. The cork characterization was performed by confocal fluorescence microscopy (CLSM), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), allowing the identification of lignin, suberin and polysaccharides (cellulose and hemicellulose) as the main components of the cork. The best conditions for extraction were as follows: rotation velocity of the disk, 2000 rpm; extraction time, 45 min; and sample volume, 20 mL. The analytical features of the developed method show that calibration curves for all analytes have R2 values higher than 0.99. The absolute recoveries were higher than 63%, and the precision, expressed as relative standard deviation, ranged from 2 to 16%. The LOD and LOQ ranges were 3-19 and 10-62 ng L-1, respectively. The proposed method was applied to the analysis of wastewater, and the concentrations of hormones in a wastewater treatment plant in Santiago, Chile, ranged from
Journal of Environmental Chemical Engineering, 2018
Abstract A simple and efficient solvent-free method for the quantification of total polychlorinat... more Abstract A simple and efficient solvent-free method for the quantification of total polychlorinated biphenyls (PCBs) in solid waste matrices by gas chromatography-mass spectrometry is proposed. Solid waste matrices spiked with Aroclor 1242 and Aroclor 1254 were used in this study. In this new approach, the cavity of the rotating disk device is loaded with the solid waste sample and water is used as leaching solvent allowing desorption of the analytes. Concomitantly a solid phase microextraction fiber is directly immersed in the water to extract the analytes. In order to improve the extraction efficiency, parameters such as pre-equilibrium, extraction time, temperature, ionic strength and the presence of an organic solvent were optimized. The values obtained for limits of detection (LOD) and limits of quantification (LOQ) are suitable for the determination of total PCBs in solid wastes and, subsequently, the most appropriate destination for the disposal of the waste can be selected. The accuracy and precision of the method exhibited satisfactory results, providing relative recoveries of 80.2–96.0% for total PCBs (at three spiked levels) and the relative standard deviations were between 2.5% and 15.5%. These results showed that the proposed method is a promising alternative for the determination of PCBs in solid wastes.
Uploads
Papers by Milton Moreano