Selective extraction and determination of vitamin B12 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: 3.5). 08/2012; 97:521-6. DOI: 10.1016/j.talanta.2012.05.008
Source: PubMed

ABSTRACT 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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