Un novedoso nanomaterial magnético híbrido funcionalizado con un líquido iónico polimérico para la extracción y separación de especies inorgánicas de telurio en muestras de agua

En el presente trabajo se estudió la aplicación de un novedoso nanomaterial magnético híbrido, compuesto por nanopartículas (NPs) de magnetita (Fe3O4) y líquidos iónicos poliméricos (PILs). Combinando las propiedades magnéticas de las NPs y las excelentes propiedades extractantes de los PILs, el híbrido se aplicó para la retención de especies inorgánicas de telurio en muestras acuosas con alta eficiencia y mínimo consumo de material y reactivos. Diversos factores relacionados con el proceso de extracción y de retroextracción, tales como la masa de extractante, el tiempo y medio de extracción, uso de agentes de complejación y potenciales eluyentes, entre otros, fueron evaluados independientemente utilizando espectroscopía de absorción atómica con atomización electrotérmica como método de detección de Te. Los ya mencionados factores se optimizaron para obtener una extracción total y selectiva de las dos principales especies inorgánicas del analito: Te(IV) y Te(VI), a valores de pH de 1,5 y 5, respectivamente. Asimismo, las propiedades magnéticas del material híbrido simplificaron enormemente la separación de este tras la extracción, mediante la utilización de un imán externo. La miniaturización hace al proceso atractivo desde el punto de vista ambiental, ya que minimiza el uso de reactivos y la generación de desechos potencialmente perjudiciales para el medio ambiente. Por otro lado, la metodología cuenta con un enorme potencial analítico, dada la factibilidad para incorporar a esta en protocolos de preconcentración y cuantificación del analito en diversas muestrasFil: Llaver, Mauricio. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y NaturalesFil: Wuilloud, Rodolfo G. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturale

Selenized garlic: a future prospect or already a current functional food?

In the last years, functional foods have awakened consumer, scientific and business interest. A commonly found vegetable in such kind of foods includes garlic (Allium sativum). By its ability for selenium (Se) bio-accumulation, garlic can turn into an attractive option of selenized food. Selenium is an essential micronutrient for many organisms including plants, animals, and humans. It is an important trace element due to its antioxidant properties and plays a main role in prevention of cancer and cardiovascular diseases. Nowadays, there is an increasing interest in the study of Se speciation due to the different roles that each species manifests in toxicological and nutrition fields. However, Se exhibits a narrow interval between toxicity and essentiality, which is puzzling toxicologists and alarming nutritionists and legislators. In the present review, an overview on the development of selenized garlic studies and its potential implementation in Argentine production is exposed. The development of novel foods with added value such us selenized garlic could be an attractive alternative for local market. Moreover, it becomes a good offering for factory owners, considering that Mendoza represents about 85% of total garlic production in the country.In the last years, functional foods have awakened consumer, scientific and business interest. A commonly found vegetable in such kind of foods includes garlic (Allium sativum). By its ability for selenium (Se) bio-accumulation, garlic can turn into an attractive option of selenized food. Selenium is an essential micronutrient for many organisms including plants, animals, and humans. It is an important trace element due to its antioxidant properties and plays a main role in prevention of cancer and cardiovascular diseases. Nowadays, there is an increasing interest in the study of Se speciation due to the different roles that each species manifests in toxicological and nutrition fields. However, Se exhibits a narrow interval between toxicity and essentiality, which is puzzling toxicologists and alarming nutritionists and legislators. In the present review, an overview on the development of selenized garlic studies and its potential implementation in Argentine production is exposed. The development of novel foods with added value such us selenized garlic could be an attractive alternative for local market. Moreover, it becomes a good offering for factory owners, considering that Mendoza represents about 85% of total garlic production in the country

Efficient Low-Cost Procedure for Microextraction of Estrogen from Environmental Water Using Magnetic Ionic Liquids

In this study, three magnetic ionic liquids (MILs) were investigated for extraction of four estrogens, i.e., estrone (E1), estradiol (E2), estriol (E3), and ethinylestradiol (EE2), from environmental water. The cation trihexyl(tetradecyl)phosphonium ([P66614]+), selected to confer hydrophobicity to the resulting MIL, was combined with tetrachloroferrate(III), ferricyanide, and dysprosium thiocyanate to yield ([P66614][FeCl4]), ([P66614]3[Fe(CN)6]), and ([P66614]5[Dy(SCN)8]), respectively. After evaluation of various strategies to develop a liquid-liquid microextraction technique based on synthesized MILs, we placed the MILs onto a magnetic stir bar and used them as extracting solvents. After extraction, the MIL-enriched phase was dissolved in methanol and injected into an HPLC-UV for qualitative and quantitative analysis. An experimental design was used to simultaneously evaluate the effect of select variables and optimization of extraction conditions to maximize the recovery of the analytes. Under optimum conditions, limits of detection were in the range of 0.2 (for E3 and E2) and 0.5 μg L-1 (for E1), and calibration curves exhibited linearity in the range of 1-1000 μg L-1 with correlation coefficients higher than 0.998. The percent relative standard deviation (RSD) was below 5.0%. Finally, this method was used to determine concentration of estrogens in real lake and sewage water samples

Un modelo simple del fenómeno de difusión que tiene lugar durante el proceso de desamarizado de aceitunas verdes de mesa

The change in the concentration of sodium and calcium ions in the olive flesh and in the lye during the debittering process was quantified. The average concentration of Na increased from 0.0045 to 0,395 meq Na/g of olive flesh and the concentration of Ca increased from 0.018 to 0.0252 meq Ca/g of olive flesh. The firmness of the olives decreased almost linearly from 375 gf to 235 gf during the alkali treatment. The olives also suffered a 25.9% loss in their initial content of reducing sugars. A hypothetical simplified description of the dynamic of ionic charge changes and unwinding of the pectinic structure during the debittering process of green olives has been proposed. In addition, the effective diffusion coefficients were calculated for sodium and calcium using a diffusion model for a composite flat plate and constant diffusion coefficients. The coefficients for both solutes were in the order of 10–12 m2/s for the skin and 10–10 m2/s for the flesh. In both cases, the diffusion coefficients of Na were larger than the diffusion coefficients of Ca.Se ha cuantificado el cambio en la concentración de sodio y calcio en la pulpa y en la lejía durante el tratamiento alcalino de aceitunas. La concentración promedio de sodio en la pulpa aumentó de 0,0045 a 0,395 meq Na/g mientras que la de calcio creció de 0,018 a 0,0252 meq Ca/g. La textura de las aceitunas disminuyó casi linealmente de 375 gf a 235 gf durante el tratamiento alcalino. Las aceitunas sufrieron una perdida de azúcares reductores del 25.9%. Se ha propuesto una hipotética y simplificada descripción de la dinámica de los cambios de carga iónica y el desenrrollamiento de las pectinas durante el desamarizado de las aceitunas. También se calculó el coeficiente efectivo de difusión para sodio y calcio usando un modelo de difusión para una placa compuesta. Los coeficientes resultaron en el orden de 10–12 m2/s para la piel y 10–10 m2/s para pulpa. En ambos casos el coeficiente de difusión de Na fue mayor que el de Ca

Development of preconcentration strategies for the simultaneous ultratrace determination of As, Cd and Pb in foods by ICP-OES: knotted-reactor vs. dispersive liquid–liquid microextraction

Determination of As, Cd and Pb in food samples by means of inductively coupled plasma optical emission spectrometry (ICP-OES) is challenging due to detection limits being close to the maximum levels established by current international food security policies. This work evaluates the benefits and drawbacks of knotted reactor extraction (KR) and dispersive liquid–liquid microextraction (DLLME) for the simultaneous ultratrace determination of the above-mentioned elements by ICP-OES. To this end, ICP-OES experimental conditions were optimized to minimize the negative effects of organics on plasma characteristics. Next, both KR and DLLME were optimized using the experimental design for the simultaneous As, Cd and Pb preconcentration. KR- and DLLME-ICP-OES methods were compared and applied to the analysis of different food samples, representative of the commodities regulated by the EU policy. Results in this work show that both KR and DLLME allow successful toxic element analysis in foods according to current EU policies. Nevertheless, DLLME is a more attractive approach than KR. First, DLLME allows the simultaneous determination of As, Cd and Pb, while KR is just limited to the last two elements, since As-complexes are not efficiently retained within the system. When compared to conventional ICP-OES analysis (i.e., no preconcentration), DLLME improves limits of detection (LOD) on average by 40-fold for As, Cd and Pb, whereas KR improves it by just 10-fold. For both methodologies, LOD improvement is derived from the preconcentration procedure as well as the beneficial effect of organics on aerosol generation and transport to the plasma compared to aqueous samples. Finally, DLLME affords higher sample throughput and consumption index than KR.The authors would like to thank the Generalitat Valenciana (Project GV/2014/138) for the financial support of this work. D. Martínez-Rubio thanks the University of Alicante for the research fellowship (UAFPU2015-5998). This work was also supported by Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Agencia Nacional de Promoción Científica y Tecnológica (FONCYT) (Project PICT-2016-2506-BID) and Universidad Nacional de Cuyo (Project 06/M129) (Argentina)

State-of-the-art analytical methods based on ionic liquids for food and beverage analysis

The use of ionic liquids (ILs) in different fields of analytical chemistry has increased exponentially in recent years, leading to the development of new technologies that try to respect the guidelines proposed by Green Chemistry. ILs are considered relatively ecological compounds due to their thermal stability and non-volatility at room temperature, which prevents their release into the atmosphere. However, recent studies have shown that the growing number of applications that involve them has led to pollution to the aquatic and terrestrial compartments. Despite this, ILs have become environmentally friendlier alternatives to conventional toxic organic solvents for their application in microextraction techniques, both as liquid phases or combined with nanomaterials for solid phase extraction. In addition to this, the use of ILs as mobile and stationary phase additives in chromatographic techniques has introduced substantial improvements in these separation techniques. Likewise, advanced electrodes have been obtained thanks to the functionalization of nanomaterials with ILs for more selective and sensitive electrochemical determinations. In this review, the use of ILs in the development of innovative and efficient analytical methods applied for food and beverage analysis is revised. Special emphasis is made on the environmental impact of the reviewed applications, including their analysis via the AGREE software, which allows the obtention of a numerical estimation of the greenness of an analytical method. In addition, critical issues and future challenges arising from the application of ILs in microextraction, chromatography and electrochemical techniques are discussed

State-of-the-art extraction and separation of enantiomers through the application of alternative solvents

Enantiomeric separation is an increasing research area, as well as the application of alternative solvents replacing classic volatile, flammable and toxic organic solvents. Among these novel solvents, chiral ionic liquids (CILs) have been widely used in sample preparation (extraction), gas chromatography, liquid chromatography, capillary electrophoresis and other techniques involved in enantioseparation. Likewise, surfactants and deep eutectic solvents have gained increasing attention in the last years because they are valid alternatives to CILs with a lower cost and/or diminished environmental impact. This review provides a comprehensive overview of the latest developments using these modern solvents applied to enantioseparations, focusing mainly on the applications of CILs. Furthermore, separation and preconcentration of chiral analytes in different matrices are also reviewed in this article. Articles published since 2017 to present were reviewed in this work. Critical discussion on their analytical application and future challenges related to their use are also included in this review.EEA La ConsultaFil: Quintas, Pamela Y. Universidad Nacional de Cuyo. Laboratorio de Química Analítica para Investigación y Desarrollo (QUIANID); ArgentinaFil: Quintas, Pamela Y. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Interdisciplinario de Ciencias Básicas; ArgentinaFil: Quintas, Pamela Y. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto Interdisciplinario de Ciencias Básicas; ArgentinaFil: Quintas, Pamela Y. Universidad Nacional de Cuyo. Facultad Ciencias Agrarias; ArgentinaFil: Fiorentini, Emiliano F. Universidad Nacional de Cuyo. Laboratorio de Química Analítica para Investigación y Desarrollo (QUIANID); ArgentinaFil: Fiorentini, Emiliano F. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Interdisciplinario de Ciencias Básicas; ArgentinaFil: Fiorentini, Emiliano F. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto Interdisciplinario de Ciencias Básicas; ArgentinaFil: Fiorentini, Emiliano F. Universidad Nacional de Cuyo. Facultad Ciencias Agrarias; ArgentinaFil: Llaver, Mauricio. Universidad Nacional de Cuyo. Laboratorio de Química Analítica para Investigación y Desarrollo (QUIANID); ArgentinaFil: Llaver, Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Interdisciplinario de Ciencias Básicas; ArgentinaFil: Llaver, Mauricio. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto Interdisciplinario de Ciencias Básicas; ArgentinaFil: Llaver, Mauricio. Universidad Nacional de Cuyo. Facultad Ciencias Agrarias; ArgentinaFil: Gonzalez, Roxana Elizabeth. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria La Consulta; ArgentinaFil: Gonzalez, Roxana Elizabeth. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Wuilloud, Rodolfo G. Universidad Nacional de Cuyo. Laboratorio de Química Analítica para Investigación y Desarrollo (QUIANID); ArgentinaFil: Wuilloud, Rodolfo G. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Interdisciplinario de Ciencias Básicas; ArgentinaFil: Wuilloud, Rodolfo G. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto Interdisciplinario de Ciencias Básicas; ArgentinaFil: Wuilloud, Rodolfo G. Universidad Nacional de Cuyo. Facultad Ciencias Agrarias; Argentin