Vortex Assisted Liquid-Liquid-Liquid Microextraction For The Determination Of Carvedilol In Biological Fluids
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Date
2015-09
Authors
Yap, Hui Fang
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
A new, rapid and sensitive microextraction technique named vortex-assisted liquid-liquid-liquid microextraction (VALLLME) is proposed. The extraction involves two steps. First, a vortex-assisted liquid-liquid microextraction (VALLME) procedure was used to extract the analytes from a relatively large volume of sample (donor phase) to a small volume of organic solvent (intermediate phase). Next, a micro-vortex-assisted liquid-liquid extraction (VA-μ-LLE) was used to extract the target analytes from the intermediate phase to a smaller volume of aqueous solution (acceptor phase). The final extract (acceptor phase) can be directly injected into the high performance liquid chromatography (HPLC) or capillary electrophoresis (CE) units without any further treatments. The selection of the intermediate phase and the manipulation of pH are key parameters that ensure good extraction efficiency of the technique. The optimum extraction conditions were: toluene as intermediate phase (150 μL); pH of the donor phase, 9.5; vortex time of the VALLME, 45 s (maximum speed, 2500 rpm); 0.1 M HCl (15 μL) as acceptor phase; vortexing time of the VA-μ-LLE, 75 s (maximum stirring speed, 2500 rpm) and salt concentration in the donor phase, 5 % (w/v). Under these conditions, enrichment factor of 418-fold was achieved. Calibration curve was linear over the range 5–1000 μg L–1 (r2 = 0.9997). Repeatability for three different concentration levels (5, 250 and 1000 μg L–1) were 9.1, 3.2 and 2.2 %, respectively. LOD and LOQ obtained were 0.20 and 0.59 μg L–1, respectively. The proposed microextraction technique was used in combination with HPLC and CE and was successfully applied for the determination of carvedilol in spiked biological fluids such as urine and plasma.
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Keywords
Vortex-assisted liquid-liquid-liquid microextraction , is proposed.