1,028 research outputs found
State-of-the-art extraction and separation of enantiomers through the application of alternative solvents
No full textEnantiomeric 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
Highly selective ionic liquid-based microextraction method for sensitive trace cobalt determination in environmental and biological samples
No full textA simple and rapid dispersive liquid?liquid microextraction procedure based on an ionic liquid (ILDLLME) was developed for selective determination of cobalt (Co) with electrothermal atomic absorption spectrometry (ETAAS) detection. Cobalt was initially complexed with 1-nitroso-2-naphtol (1N2N) reagent at pH 4.0. The IL-DLLME procedure was then performed by using a few microliters of the room temperature ionic liquid (RTIL) 1-hexyl-3-methylimidazolium hexafluorophosphate [C6mim][PF6] as extractant while methanol was the dispersant solvent. After microextraction procedure, the Co-enriched RTIL phase was solubilized in methanol and directly injected into the graphite furnace. The effect of several variables on Co-1N2N complex formation, extraction with the dispersed RTIL phase, and analyte detection with ETAAS, was carefully studied in this work. An enrichment factor of 120 was obtained with only 6 mL of sample solution and under optimal experimental conditions. The resultant limit of detection (LOD) was 3.8 ng/L, while the relative standard deviation (RSD) was 3.4% (at 1 ug/L Co level and n = 10), calculated from the peak height of absorbance signals. The accuracy of the proposed methodology was tested by analysis of a certified reference material. The method was successfully applied for the determination of Co in environmental and biological samples.Fil: Berton, Paula. 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 as ion-pairing reagent for liquid-liquid microextraction and preconcentration of arsenic species in natural waters followed by ETAAS
No full textA simple and highly efficient microextraction methodology was developed for arsenate [As(V)], arsenite [As(III)] and organic arsenic (i.e., DMA and MMA) preconcentration and determination based on the novel use of tetradecyl(trihexyl)phosphonium chloride ionic liquid (CYPHOS® IL 101) as an ionpairing reagent. As(V) species was selectively separated by forming As(V)-molybdate heteropoly acid [As(V)-MHPA] complex with molybdenum, followed by ion-pairing reaction with CYPHOS® IL 101 and microextraction in chloroform. Arsenic detection was performed by electrothermal atomic absorption spectrometry (ETAAS). Under optimum conditions, the analyte extraction efficiency was 99% and yielded a preconcentration factor of 125 with only 5.00 mL of sample. The detection limit was 0.002 mg L-1 as As(V). The relative standard deviation (RSD) for six replicate measurements at 1.5 mg L-1 of As were 4.1%, 4.9% and 5.0% for As(V), As(III) and total organoarsenicals, respectively. The proposed methodology was successfully applied for As speciation analysis in several types of water samples.Fil: Monasterio, Romina Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Tecnológicas. Laboratorio de Investigaciones y Servicios Ambientales Mendoza; ArgentinaFil: Wuilloud, Rodolfo German. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
On-line preconcentration and determination of chromium in parenteral solutions by flow injection - Flame atomic absorption spectrometry
No full textAn on-line chromium preconcentration and determination system implemented with flame atomic absorption spectrometry (FAAS) associated to flow injection (FI) was studied. For the retention of chromium, 4-(2-Thiazolylazo)-resorcinol (TAR) and Amberlite XAD-16 were used, at pH 5.0. The Cr-TAR complex was removed from the micro-column with ethanol. An enrichment factor of 50 was obtained for the preconcentration of 50 ml of sample solution. The detection limit value for the preconcentration of 50 ml of aqueous solution of Cr was 20 ng l-1. The precision for ten replicate determinations at the 5 μg l-1 Cr levels was 2.9% relative standard deviation (RSD), calculated from the peak heights obtained. The calibration graph using the preconcentration system for chromium was linear with a correlation coefficient of 0.9997 at levels near the detection limits up to at least 100 μg l-1. The method was successfully applied to the determination of chromium in parenteral solution samples. © 2002 Elsevier Science B.V. All rights reserved.Fil: Wuilloud, Gustavo M.. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; ArgentinaFil: Wuilloud, Rodolfo German. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Altamirano, Jorgelina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; ArgentinaFil: Olsina, Roberto Antonio. 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: 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; Argentin
Separation and preconcentration of inorganic Se species in tap and natural waters using unfunctionalized nanosilica as sorption material in dispersive micro-solid phase extraction
No full textA highly sensitive and selective method based on dispersive micro-solid phase extraction (D-μ-SPE) technique was developed for the determination of inorganic Se species. A very simple and fast preconcentration procedure involving the use of pure nanosilica for the extraction of Se(IV) complexed with ammonium pyrrolidine dithiocarbamate (APDC) was applied. Elution of the retained Se(IV) species from nanosilica was achieved with ethyl acetate followed by electrothermal atomic absorption spectrometry determination. For speciation analysis, Se(VI) was selectively quantified based on the difference between the concentrations of total inorganic Se and Se(IV) after a pre-reduction step. The interaction between the analyte and the extractant was characterized by FT-IR and an adsorption isotherm study. A 90% extraction efficiency was achieved after optimization of all factors concerning the extraction and elution steps, such as pH, ionic strength and type of chelating agent. Optimized conditions included pH = 2.0, 4.9 μmol L−1 APDC and the use of 1 mg nanosilica as adsorbent. A limit of detection of 1.4 ng L−1, a relative standard deviation of 4.8% and a 90-fold enhancement factor were obtained with 10 mL of sample. The developed method was finally applied to water samples from different origins and compositions, including rain, tap, underground, and sea.Fil: Llaver, Mauricio. 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. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; ArgentinaFil: Wuilloud, Rodolfo German. 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. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; Argentin
Enhanced spectrophotometric detection of Hg in water samples by surface plasmon resonance of Au nanoparticles after preconcentration with vortex-assisted liquid-liquid microextraction
No full textThis 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
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
No full textEn 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 Naturales.Fil: Wuilloud, Rodolfo G. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales
Studying the effect of an ionic liquid on cloud point extraction technique for highly efficient preconcentration and speciation analysis of tellurium in water, soil and sediment samples
No full textA simple, novel and highly sensitive ionic liquid-assisted cloud point extraction (IL-CPE) and preconcentration method was developed for the determination and speciation analysis of tellurium, using 1-octyl-3-methylimidazolium chloride as an additive for improving the extraction efficiency of Triton X-114. The Te(IV) species was complexed with ammonium pyrrolidine dithiocarbamate, extracted into the micellar IL/surfactant phase and then directly measured by electrothermal atomic absorption spectrometry (ETAAS). The total Te concentration was obtained after a pre-reduction step and Te(VI) concentration was calculated as the difference between total Te and Te(IV). Several parameters, including the type and concentration of IL and surfactant, time and temperature of the IL-CPE procedure and ETAAS conditions were thoroughly evaluated and optimized. In addition, the action mechanism of the IL on CPE was studied by fluorescence measurements using Laurdan as a polarity probe. The decrease in the internal polarity caused by the incorporation of the IL into the micelles was responsible for the improvement in the extraction efficiency. Under the optimized conditions, a sensitivity enhancement factor of 87 and an extraction efficiency of 90% were achieved. Limits of detection of 1.1 and 1.7 ng L−1 and relative standard deviations of 3.9% and 5.0% for Te(IV) and Te(VI), respectively, were obtained. The developed IL-CPE method was successfully applied for Te speciation analysis in matrices of different complexities, such as waters (tap, underground and seawater), soil and sediment.Fil: Llaver, Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Wuilloud, Rodolfo German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentin
Ionic liquids: multi‐role actors in elemental speciation analysis
No full textElemental speciation is a concept that results extremely relevant in nutritional, toxicity and environmental studies as it generates crucial information to fully understand the bioavailability and toxicity of an element1. However, high selectivity and sensitivity are the main demands to be covered by analytical methods for trace elements speciation studies. To accomplish these goals, the combination of a selective separation technique with highly sensitive detectors has been the main strategy. Although any kind of separation technique is feasible, chromatographic techniques are easily coupled to elemental specific detectors. Likewise, non-chromatographic separation techniques can also be used for speciation analysis, but with a more limited separation power. In any case, both methodological approaches require constant improvements due to the high complexity to analyze the speciation of some elements and the difficulty imposed by sample matrices. Ionic Liquids (ILs) are recognized as modern solvents with remarkable properties such as low volatility, high conductivity, and the possibility of offering multiple interactions with different chemical species. Therefore, they have found wide application in different fields of analytical chemistry. In fact, ILs have been proposed as highly efficient extraction phases for separation and preconcentration, while their particular interactions with solutes show them as excellent tools in chromatography as well2. Moreover, the potential of ILs for the separation and preconcentration of trace elements can be further extended beyond their own limits when they are combined with different types of nanomaterials, and properties such as magnetism can be imparted to these extraction phases for more practical microextraction procedures. In this lecture, recent advances on the development of non-chromatographic and chromatographic separation methods using ILs for elemental speciation analysis will be presented. The development of modern liquid-liquid and solid-phase microextraction techniques (e.g. dispersive liquid-liquid microextraction (DLLME) and dispersive microsolid phase extraction (D-µ-SPE)) based on ILs and their combination with certain nanomaterials will be discussed. Also, the application of ILs for the determination of elemental species by HPLC-elemental specific detector hyphenated techniques will be presented, along with the benefits and potential drawbacks of their application when they are coupled to atomic spectrometry-based techniques.Fil: Wuilloud, Rodolfo German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; ArgentinaColloquium Spectroscopicum Internationale XLI; First Latin-American Meeting on Laser Induced Breakdown SpectroscopyCiudad de MéxicoMéxicoUniversidad Nacional Autónoma de MéxicoInstituto de Ciencias Aplicadas y TecnologíaSociedad Mexicana de FísicaSociedad Química de Méxic
Cold vapor ionic liquid-assisted headspace single-drop microextraction: A novel preconcentration technique for mercury species determination in complex matrix samples
No full textA novel technique named cold vapor ionic liquid-assisted headspace single drop microextraction (CVILAHS-SDME) was developed for Hg species determination at trace levels. Inorganic (InHg) and organomercury (OrgHg) species separation, preconcentration and determination were performed by in situ cold vapor generation (CV) followed by headspace extraction with a suspended microdrop of a low cost RTIL, i.e. tetradecyl(trihexyl)phosphonium chloride (CYPHOS_ IL 101), and direct injection in electrothermal atomic absorption spectrometry (ETAAS). Stannous chloride (SnCl2) was used to reduce Hg(2+) to volatile Hg(0), while oxidation of OrHg species permitted the determination of total Hg. OrHg species concentration was evaluated based on the difference between total Hg and InHg concentration. Different variables of CV-ILAHS-SDME technique, such as cold vapor generation conditions, temperature, sample and solvent volume, extraction time, and stirring rate were carefully studied. The analytical sensitivity was enhanced by a factor of 75. A low detection limit (10 ng/L) and good precision (relative standard deviation of 4.6% at 0.25 mg/L Hg and n=10) were achieved. Experimental results demonstrated that CV-ILAHS-SDME using CYPHOS_ IL 101 is a rapid, costeffective and green microextraction technique for Hg determination in samples with a complex matrix, such as sea water, fish tissues, hair and wine.Fil: Martinis, Estefanía Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; ArgentinaFil: Wuilloud, Rodolfo German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; Argentin
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