Selective extraction and determination of vitamin B-12 in urine by ionic liquid-based aqueous two-phase system prior to high-performance liquid chromatography

Laboratory of Analytical Chemistry for Research and Development (QUIANID), Instituto de Ciencias Básicas, Universidad Nacional de Cuyo, Padre J. Contreras 1300, Parque Gral. San Martín, M5502JMA Mendoza, Argentina.
Talanta (Impact Factor: 3.55). 08/2012; 97:521-6. DOI: 10.1016/j.talanta.2012.05.008
Source: PubMed


A rapid and simple extraction technique based on aqueous two-phase system (ATPS) was developed for separation and enrichment of vitamin B(12) in urine samples. The proposed ATPS-based method involves the application of the hydrophilic ionic liquid (IL) 1-hexyl-3-methylimidazolium chloride and K(2)HPO(4). After the extraction procedure, the vitamin B(12)-enriched IL upper phase was directly injected into the high performance liquid chromatography (HPLC) system for analysis. All variables influencing the IL-based ATPS approach (e.g., the composition of ATPS, pH and temperature values) were evaluated. The average extraction efficiency was 97% under optimum conditions. Only 5.0 mL of sample and a single hydrolysis/deproteinization/extraction step were required, followed by direct injection of the IL-rich upper phase into HPLC system for vitamin B(12) determination. A detection limit of 0.09 μg mL(-1), a relative standard deviation (RSD) of 4.50% (n=10) and a linear range of 0.40-8.00 μg mL(-1) were obtained. The proposed green analytical procedure was satisfactorily applied to the analysis of samples with highly complex matrices, such as urine. Finally, the IL-ATPS technique could be considered as an efficient tool for the water-soluble vitamin B(12) extraction.

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Available from: Rodolfo G Wuilloud, Nov 12, 2014
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    • "In this technique, analyte extraction is performed with low viscous and hydrophilic ILs. Separation of phases is induced by salt addition (generally inorganic) to the homogeneous aqueous solution [116]. In the second HLLME method, called in-situ solvent formation microextraction (ISFME), sodium hexafluorophosphate (NaPF6) was used as ion-pairing agent. "
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    ABSTRACT: 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.
    TrAC Trends in Analytical Chemistry 09/2014; 60. DOI:10.1016/j.trac.2014.04.012 · 6.47 Impact Factor
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    • "Different ABP systems and their corresponding phase 35 diagrams based on different types of ionic liquids and inorganic 36 salts have been also reported which are known as ionic liquid- 37 based aqueous biphasic (IL-based ABP) systems [13] [14]. Some of 38 these systems have been used for separation and determination of 39 selected biological compounds [15] [16] [17] [18]. In recent years, ionic 40 liquids (ILs) have been increasingly used for separations [19] 41 because of their unique specifications such as negligible volatility 42 and non-flammability under ambient conditions, wide liquid 43 temperature range, high thermal and chemical stability, high 44 solvating capacity for organic, inorganic and organometallic 45 compounds and their finely tunable physicochemical properties 46 when different cations or anions are used [20] [21]. "
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    ABSTRACT: In this paper partitioning behaviors of reactive red-120, 4-(2-pyridylazo)-resorcinol, and methyl orange as model azo dyes in ionic liquid-based aqueous biphasic systems were studied. For designing aqueous biphasic systems and investigating the partitioning of the model dyes, phase diagrams and binodal curves were obtained at 25 °C for [C4mim][Br]/salt systems at different pH values. It was found that the partition coefficients of the studied dyes depended on their chemical structures, pH of the aqueous phase, temperature and composition of the aqueous biphasic system. Ionic liquid-based aqueous biphasic extraction was an efficient and suitable method for partitioning of dyes into ionic liquid-rich top phase. Efficient extraction of dyes into IL phase was done within 1 min. The hydrophilic ionic liquid 1-butyl-3-methylimidazolium bromide, [C4mim][Br], in top phase was efficiently recovered by using the hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate, [C4mim][PF6]. In the recycling process, almost no dye was extracted into [C4mim][PF6] phase.
    Journal of Environmental Chemical Engineering 01/2013; 2(1). DOI:10.1016/j.jece.2013.12.005
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    ABSTRACT: 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.
    Analytical and Bioanalytical Chemistry 05/2013; 405(24). DOI:10.1007/s00216-013-6950-x · 3.44 Impact Factor
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