Continuous-Flow Microelectroextraction for Enrichment of Low Abundant Compounds

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• 作者：Jan-Willem Schoonen ; Vincent van Duinen ; Amar Oedit ; Paul Vulto ; Thomas Hankemeier ; Petrus W. Lindenburg
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：August 19, 2014
• 年：2014
• 卷：86
• 期：16
• 页码：8048-8056
• 全文大小：416K
• ISSN：1520-6882

文摘

We present a continuous-flow microelectroextraction flow cell that allows for electric field enhanced extraction of analytes from a large volume (1 mL) of continuously flowing donor phase into a micro volume of stagnant acceptor phase (13.4 渭L). We demonstrate for the first time that the interface between the stagnant acceptor phase and fast-flowing donor phase can be stabilized by a phaseguide. Chip performance was assessed by visual experiments using crystal violet. Then, extraction of a mixture of acylcarnitines was assessed by off-line coupling to reversed phase liquid chromatography coupled to time-of-flight mass spectrometry, resulting in concentration factors of 80.0 卤 9.2 times for hexanoylcarnitine, 73.8 卤 9.1 for octanoylcarnitine, and 34.1 卤 4.7 times for lauroylcarnitine, corresponding to recoveries of 107.8 卤 12.3%, 98.9 卤 12.3%, and 45.7 卤 6.3%, respectively, in a sample of 500 渭L delivered at a flow of 50 渭L min^鈥? under an extraction voltage of 300 V. Finally, the method was applied to the analysis of acylcarnitines spiked to urine, resulting in detection limits as low as 0.3鈥? nM. Several putative endogenous acylcarnitines were found. The current flowing-to-stagnant phase microelectroextraction setup allows for the extraction of milliliter range volumes and is, as a consequence, very suited for analysis of low-abundant metabolites.