An easily prepared graphene oxide-ionic liquid hybrid nanomaterial for micro-solid phase extraction and preconcentration of Hg in water samples

A preconcentration method based on the use of graphene oxide (GO) functionalized with an ionic liquid (IL) was developed for trace Hg determination in water samples. The IL-GO hybrid nanomaterial was prepared by a simple procedure to functionalize GO with the IL 1-butyl-3-dodecylimidazolium bromide ([C4C12im]Br) and its performance as a sorption material for Hg was evaluated. A microcolumn filled with the IL-GO nanomaterial was used for preconcentration and determination of Hg followed by electrothermal atomic absorption spectrometry (ETAAS) detection. Mercury was retained at pH 5.0 and 20% (v/v) HNO3 was used for the elution of Hg from the microcolumn. The effects of different variables, including the sample volume, extraction time, sample flow rate, type and concentration of eluent and eluent flow rate were carefully studied. High retention efficiency (100%) was achieved with the proposed IL-GO sorption nanomaterial without the need for additional chelating reagents or derivatization reagents, which is an important advantage compared with traditional preconcentration methods. A sensitivity enhancement factor of 100 and a low detection limit of 14 ng L-1 were obtained under optimal experimental conditions. The proposed method can be considered as a simple, cost-effective and efficient alternative for Hg determination in water samples like river, rain, mineral and tap water.Fil: Cruz Sotolongo, Annaly. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo; ArgentinaFil: Martinis, Estefanía Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo; ArgentinaFil: Wuilloud, Rodolfo German. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo; Argentin

Aplicación de nanomateriales basados en aluminosilicatos para la remoción de contaminantes como el arsénico desde matrices acuosas

Por sus propiedades particulares y potencial aplicabilidad, los nanomateriales han sido objeto de estudio en las últimas décadas. La disminución del tamaño al orden de los nanómetros modifica las propiedades ópticas (coloración, absorción, luminiscencia y emisión), mecánicas (ultra endurecimiento y anti oxidación), térmicas (intercambio de calor, punto de fusión y resistencia térmica), eléctricas (conductividad y aislamiento), magnéticas (magneto-resistencia colosal) y químicas de los materiales. En el caso específico de los materiales basados en aluminosilicatos, en la escala nanométrica mejoran notablemente sus propiedades adquiriendo comportamientos únicos tales como, superplasticidad, maquinabilidad, resistencia, tenacidad, y además la capacidad de ser biocompatibles y amigables con el ambiente. Dentro de estos materiales podemos citar a los nanotubos de aluminosilicatos (imogolita, HOSiO3Al2(OH)3) y nanopartículas de leucita (KAlSi2O6), albita (NaAlSi3O8) y nefelina (NaAlSiO4), que en los últimos años han despertado especial interés debido a sus aplicaciones. Estos nanomateriales presentan características físico-químicas que le otorgan un gran potencial para su aplicación como sorbentes selectivos. Los nanomateriales de aluminosilicatos se presentan como una alternativa al uso de materiales convencionales ya que ofrecen un amplio espectro de propiedades particulares las cuales pueden ser convenientemente sintonizadas dependiendo de la aplicación para el desarrollo de métodos de extracción y separación amigables con el ambiente, por lo que presentan un gran potencial en aplicaciones ambientales. El presente plan tiene como objetivo desarrollar nuevas tecnologías basadas en materiales nanométricos híbridos para su aplicación en Química Ambiental. Se desarrollarán distintas combinaciones híbridas de los nanomateriales con moléculas orgánicas, inorgánicas y otros nanomateriales con el fin de incrementar sus capacidades de sorción. La implementación de nanomateriales basados en aluminosilicatos como nanotubos y nanopartículas en sistemas de extracción en fase sólida, será el fundamento para la remoción de contaminantes como el arsénico (As). Se prestará particular atención a la aplicación de los métodos desarrollados para el tratamiento de agua de zonas contaminadas de la provincia de Mendoza.Due to their particular properties and potential applicability, nanomaterials have been studied in recent decades. The decrease in size to the order of nanometers modifies the optical (coloration, absorption, luminescence and emission), mechanical (ultra-hardening and anti-oxidation), thermal (heat exchange, melting point and thermal resistance), electrical (conductivity and insulation), magnetic (colossal magneto-resistance) and chemical properties of the materials. In the specific case of materials based on aluminosilicates, at the nanometric scale, they remarkably improve their properties by acquiring unique behaviors such as superplasticity, machinability, resistance, tenacity, and also the ability to be biocompatible and friendly to the environment. Among these materials we can mention nanotubes of aluminosilicates (imogolite, HOSiO3Al2(OH)3) and nanoparticles of leucite (KAlSi2O6), albita (NaAlSi3O8) and nepheline (NaAlSiO4), which in recent years have aroused special interest due to their applications. These nanomaterials have physical and chemical characteristics that give them great potential for their application as selective sorbents. The nanomaterials of aluminosilicates are presented as an alternative to the use of conventional materials since they offer a wide spectrum of particular properties which can be conveniently tuned depending on the application for the development of environmentally friendly extraction and separation methods, thus, they present a great potential in environmental applications. The objective of this plan is to develop new technologies based on hybrid nanometric materials for application in Environmental Chemistry. Different hybrid combinations of nanomaterials will be developed with organic, inorganic molecules and other nanomaterials in order to increase their sorption capacities. The implementation of nanomaterials based on aluminosilicates such as nanotubes and nanoparticles in solid phase extraction systems will be the basis for the removal of contaminants such as arsenic (As). Particular attention will be paid to the application of the methods developed for the treatment of water in contaminated areas of the province of Mendoza

Tecnologías abiertas para el monitoreo de la calidad del aire: La experiencia del MACA

En las ciudades, vivimos inmersos en una atmósfera compleja y nociva que es elproducto de su frenético metabolismo y representa en la actualidad una de las mayores amenazas para la salud a nivel mundial. En general, se ha considerado una práctica normal que sean solo los expertos al servicio de un organismo científico o ambiental quienes tengan a su cargo la operación de costosas y complejas redes de monitoreo para generar y analizar datos acerca de la calidad del aire. Sin embargo, esta práctica de monitoreo parece estar en crisis y en transición hacia un nuevo paradigma más abierto e inclusivo. Amateurs, hackers, comunidades de afectadas y ciudadanos están utilizando y compartiendo los diseños de equipos científicos abiertos DIY (do it yourself), como también los datos obtenidos con estos dispositivos, cambiando no sólo cómo y por quien son obtenidos los datos, sino también por qué, para qué y cómo los mismos están siendo presentados, y accionados, en la esfera pública. En este trabajo presentaremos nuestra experiencia en el desarrollo y la experimentación con una serie de prototipos abiertos de bajo costo para el monitoreo de la calidad del aire (MACA.) alineados con este nuevo paradigma. Presentaremos las distintas características técnicas de los dispositivos, un análisis de los datos obtenidosde su calibración y sus mediciones en el aire de Mendoza. También presentaremostoda la documentación asociada al proyecto que puede ser consultada en https://gitlab.com/nanocastro/Repo_maca. En conclusión, la construcción y el uso de estos dispositivos nos ha permitido comprender mejor las potencialidades y limitaciones de dichos dispositivos para comenzar a desarrollar nuevas prácticas entorno al monitoreo de la calidad del aire a nivel local.Fil: Castro, Fernando. Universidad Nacional de Cuyo; ArgentinaFil: Clausen, María Ruth. Universidad Nacional de Cuyo; ArgentinaFil: Barbeito, María Esther. Universidad Nacional de Cuyo; ArgentinaFil: Martinis, Estefanía Mabel. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Tames, María Florencia. Universidad Tecnológica Nacional. Facultad Regional de Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Perazzo, Fabrizio. Universidad Nacional de Cuyo; ArgentinaIV Congreso Nacional de Ciencia y Tecnología AmbientalArgentinaSociedad Argentina de Ciencia y Tecnología Ambienta

Enhanced spectrophotometric detection of Hg in water samples by surface plasmon resonance of Au nanoparticles after preconcentration with vortex-assisted liquid-liquid microextraction

This article presents an efficient, simple, and cost-effective method for the determination of trace amounts of Hg by vortex-assisted liquid-liquid microextraction (VALLME) coupled to microvolume UV-Vis spectrophotometry. This method correlates changes in the intensity of localized surface plasmon resonance (LSPR) of tetraoctylammonium bromide (TOABr) coated Au nanoparticles (NPs) after interaction with Hg2+ ion. Spectroscopic measurements of the TOABr-coated Au NPs phase with particular absorption properties (strong and well-defined absorption bands) after analyte extraction by VALLME, provide an accurate and sensitive determination of Hg in water samples, comparable with measurements obtained by atomic absorption spectrometry (AAS). Different variables including sample volume, extraction time, and TOABr-coated Au NPs dispersion volume were carefully studied; final experimental conditions were 5 mL, 120 μL and 5 min respectively. The limit of detection (LOD) was 0.8 ng mL- 1. The calibration curve was linear at concentrations between the limit of quantification (LOQ) (4.9 ng mL- 1) and up to at least 120 ng mL- 1 of Hg. The relative standard deviation for six replicate determinations of 20 ng mL- 1 of Hg was 4.7%. This method exhibited an excellent analytical performance in terms of selectivity and sensitivity and it was finally applied for Hg determination in spiked tap and mineral water samples.Fil: Martinis, Estefanía Mabel. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Wuilloud, Rodolfo German. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentin

Ionic liquid-based microextraction techniques for trace-element analysis

Ionic liquid-based liquid-liquid microextraction (IL-LLME) techniques are turning into remarkable tools to develop greener sample-preparation methods in analytical chemistry. The application of ILs in LLME is receiving particular attention due to their unique physico-chemical properties, such as undetectable vapor pressure, versatility arising from high conformational possibilities, variable viscosity and density, and their miscibility with other solvents. ILs can be structurally designed to extract target analytes selectively based on unique molecular interactions, leading to highly efficient extraction procedures. In recent years, a wide range of microextraction techniques implementing ILs as successful extraction phases have been proposed. The present work outlines the latest applications of IL-LLME for trace-element analysis, focusing on those challenges arisen during the analysis of complex samples. We also discuss environmental and health aspects related to the use of IL-LLME. Finally, we present the outlook for potential applications and further developments of IL-LLME techniques.Fil: Martinis, Estefanía Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Berton, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Wuilloud, Rodolfo German. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentin

Inorganic selenium speciation analysis in Allium and Brassica vegetables by ionic liquid assisted liquid-liquid microextraction with multivariate optimization

A highly sensitive vortex assisted liquid-liquid microextraction (VA-LLME) method was developed for inorganic Se [Se(IV) and Se(VI)] speciation analysis in Allium and Brassica vegetables. Trihexyl(tetradecyl)phosphonium decanoate phosphonium ionic liquid (IL) was applied for the extraction of Se(IV)-ammonium pyrrolidine dithiocarbamate (APDC) complex followed by Se determination with electrothermal atomic absorption spectrometry. A complete optimization of the graphite furnace temperature program was developed for accurate determination of Se in the IL-enriched extracts and multivariate statistical optimization was performed to define the conditions for the highest extraction efficiency. Significant factors of IL-VA-LLME method were sample volume, extraction pH, extraction time and APDC concentration. High extraction efficiency (90%), a 100-fold preconcentration factor and a detection limit of 5.0 ng/L were achieved. The high sensitivity obtained with preconcentration and the non-chromatographic separation of inorganic Se species in complex matrix samples such as garlic, onion, leek, broccoli and cauliflower, are the main advantages of IL-VA-LLME.Fil: Castro Grijalba, Alexander. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; ArgentinaFil: Martinis, Estefanía Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; ArgentinaFil: Wuilloud, Rodolfo German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; Argentin

Room temperature ionic liquid-based microextraction for vanadium species separation and determination in water samples by electrothermal atomic absorption spectrometry

A simple microextraction technique based on room temperature ionic liquids (RTILs) for trace V(IV) and V(V) species separation and preconcentration in water samples was developed in this work. Vanadium species microextraction was achieved with a minimal amount of the RTIL 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6]) as vanadium-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (V-5-Br-PADAP) complex. The speciation analysis was performed based on a modern technique defined as temperature-controlled ionic liquid dispersive liquid phase microextraction (TILDLME). The level of V(IV) species was calculated by difference of total V and V(V) levels. Selectivity among V species was obtained with the use of 1,2-cyclohexanediaminetetraacetic acid (CDTA) as masking agent. Determination of V was developed by direct injection of the RTIL phase into the electrothermal atomic absorption spectrometer (ETAAS). A preconcentration factor of 40 was achieved with only 2 mL of sample. The limit of detection (LOD) obtained under optimum conditions was 4.9 ng L-1 and the relative standard deviation for 10 replicate determinations at the 0.5 μg L-1 V level was 4.3%, calculated at peak heights. A correlation coefficient of 0.9961 was achieved. The method was successfully applied for the speciation analysis of V in tap and river water samples.Fil: Berton, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Martinis, Estefanía Mabel. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Martinez, Luis Dante. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Wuilloud, Rodolfo German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentin

Emerging ionic liquid-based techniques for total-metal and metal-speciation analysis

Ionic liquids (ILs) are generally considered to be more environmentally friendly than common organic solvents and have unique characteristics (e.g., effectively no vapor pressure, adjustable viscosity and miscibility in aqueous phases). They are also considered to be highly efficient extractant phases to improve analyte selectivity and sensitivity, so that they are important tools for chromatographic and spectrometric analysis. We review state-of-the-art applications of ILs in analytical chemistry with special emphasis on metal determination and speciation analysis. We discuss modern microextraction techniques based on ILs [e.g., dispersive liquid-iquid microextraction (DLLME), singledrop microextraction (SDME), and on-line LLME]. Also, we comment on potential applications and developments of solid-phase extraction (SPE) techniques involving IL-modified surface materials for metal retention and preconcentration. In all cases, we review crucial parameters and practical considerations of method optimization and application. Further, we critically compare IL-based methods in terms of analytical performance and environmental compatibility.Fil: Martinis, Estefanía Mabel. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Berton, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; ArgentinaFil: Monasterio, Romina Paula. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; Argentina. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Departamento de Química; ArgentinaFil: Wuilloud, Rodolfo German. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Basicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Basicas.; Argentin

Selective determination of inorganic cobalt in nutritional supplements by ultrasound-assisted temperature-controlled ionic liquid dispersive liquid phase microextraction and electrothermal atomic absorption spectrometry

In the present work, a simple and rapid analytical method based on application of ionic liquids (ILs) for inorganic Co(II) species (iCo) microextraction in a variety of nutrient supplements was developed. Inorganic Co was initially chelated with 1-nitroso-2-naphtol (1N2N) reagent followed by a modern technique named ultrasound-assisted temperature-controlled ionic liquid dispersive liquid phase microextraction (USA-TILDLME). The extraction was performed with 1-hexyl-3-methylimidazolium hexafluorophosphate [C 6mim][PF 6] with the aid of ultrasound to improve iCo recovery. Finally, the iCo-enriched IL phase was solubilized in methanol and directly injected into an electrothermal atomic absorption spectrometer (ETAAS). Several parameters that could influence iCo microextraction and detection were carefully studied. Since the main difficulty in these samples is caused by high concentrations of potential interfering ions, different approaches were evaluated to eliminate interferences. The limit of detection (LOD) was 5.4ngL -1, while the relative standard deviation (RSD) was 4.7% (at 0.5μgL -1 Co level and n=10), calculated from the peak height of absorbance signals. Selective microextraction of iCo species was achieved only by controlling the pH value during the procedure. The method was thus successfully applied for determination of iCo species in nutritional supplements.Fil: Berton, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Tecnológicas. Laboratorio de Investigaciones y Servicios Ambientales Mendoza; ArgentinaFil: Martinis, Estefanía Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Tecnológicas. Laboratorio de Investigaciones y Servicios Ambientales Mendoza; ArgentinaFil: Martinez, Luis Dante. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Química. Área de Química Analítica; ArgentinaFil: Wuilloud, Rodolfo German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Tecnológicas. Laboratorio de Investigaciones y Servicios Ambientales Mendoza; Argentin

Bioanalytical separation and preconcentration using ionic liquids

Ionic liquids (ILs) are novel solvents that display a number of unique properties, such as negligible vapor pressure, thermal stability (even at high temperatures), favorable viscosity, and miscibility with water and organic solvents. These properties make them attractive alternatives to environmentally unfriendly solvents that produce volatile organic compounds. In this article, a critical review of state-of-the-art developments in the use of ILs for the separation and preconcentration of bioanalytes in biological samples is presented. Special attention is paid to the determination of various organic and inorganic analytes - including contaminants (e.g., pesticides, nicotine, opioids, gold, arsenic, lead, etc.) and functional biomolecules (e.g., testosterone, vitamin B12, hemoglobin) - in urine, blood, saliva, hair, and nail samples. A brief introduction to modern microextraction techniques based on ILs, such as dispersive liquid-liquid microextraction (DLLME) and single-drop microextraction (SDME), is provided. A comparison of IL-based methods in terms of their limits of detection and environmental compatibilities is also made. Finally, critical issues and challenges that have arisen from the use of ILs in separation and preconcentration techniques are also discussed.Fil: Escudero, Leticia Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Química de San Luis; ArgentinaFil: Castro Grijalba, Alexander. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis; ArgentinaFil: Martinis, Estefanía Mabel. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis; ArgentinaFil: Wuilloud, Rodolfo German. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis; Argentin