Showing papers by "Stig Pedersen-Bjergaard published in 2016"
TL;DR: In this paper, a review summarizes the performance of EME with different organic solvents and discusses several criteria for efficient solutions in EME, and highlights their personal perspective about the most promising organic solutions for EME.
Abstract: Abstract Electromembrane extraction (EME) was invented in 2006 as a miniaturized sample preparation technique for the separation of ionized species from aqueous samples. This concept has been investigated in different areas of analytical chemistry by different research groups worldwide since the introduction. Under the influence of an electrical field, EME is based on electrokinetic migration of the analytes through a supported liquid membrane (SLM), which is an organic solvent immobilized in the pores of the polymeric membrane, and into the acceptor solution. Up to date, close to 150 research articles with focus on EME have been published. The current review summarizes the performance of EME with different organic solvents and discusses several criteria for efficient solvents in EME. In addition, the authors highlight their personal perspective about the most promising organic solvents for EME and have indicated that more fundamental work is required to investigate and discover new organic solvents for EME.
66 citations
TL;DR: Electromembrane extraction of polar basic drugs from human plasma was investigated for the first time using pure bis(2-ethylhexyl) phosphite (DEHPi) as the supported liquid membrane (SLM), and this is the first report on efficient EME of highly polar analytes without using any ionic carrier in the SLM.
53 citations
TL;DR: In this article, the authors put analytical scale extraction in perspective emphasising the fundamental aspects of the underlying processes discussing the similarities and differences between different approaches and provided a classification of extraction techniques according to the mass transfer principles.
Abstract: Abstract Approaches for sample preparation are developing rapidly as new strategies are implemented to improve sample throughput and to minimize material and solvent use in laboratory methods and to develop on-site capabilities. In majority of cases the key step in sample preparation is extraction, typically used to separate and enrich compounds of interests from the matrix in the extraction phase. In this contribution, the topic of analytical scale extraction is put in perspective emphasising the fundamental aspects of the underlying processes discussing the similarities and differences between different approaches. Classification of extraction techniques according to the mass transfer principles is provided.
41 citations
TL;DR: This review summarizes recent efforts to describe the fundamentals of mass transfer in electromembrane extraction, and aim to give an up-to-date understanding of the processes involved.
Abstract: Electromembrane extraction was introduced in 2006 as a totally new sample preparation concept for the extraction of charged analytes present in aqueous samples. Electromembrane extraction is based on electrokinetic migration of the analytes through a supported liquid membrane and into a μL-volume of acceptor solution under the influence of an external electrical field. To date, electromembrane extraction has mostly been used for the extraction of drug substances, amino acids, and peptides from biological fluids, and for organic micropollutants from environmental samples. Electromembrane extraction has typically been combined with chromatography, mass spectrometry, and electrophoresis for analyte separation and detection. At the moment, close to 125 research papers have been published with focus on electromembrane extraction. Electromembrane extraction is a hybrid technique between electrophoresis and liquid-liquid extraction, and the fundamental principles for mass transfer have only partly been investigated. Thus, although there is great interest in electromembrane extraction, the fundamental principle for mass transfer has to be described in more detail for the scientific acceptance of the concept. This review summarizes recent efforts to describe the fundamentals of mass transfer in electromembrane extraction, and aim to give an up-to-date understanding of the processes involved.
38 citations
TL;DR: In this article, definitions and recommendations for symbols for the terms used in analytical extraction are presented, including exhaustive, micro-extraction, elevated temperature, microwave-and ultrasound-assisted, parallel batch, flow through systems, and membrane extraction approaches.
Abstract: Abstract Approaches for analytical-scale extraction are developing rapidly as new strategies are implemented to improve sample throughput, to minimize material use in laboratory methods, and to develop on-site capabilities. In this contribution, definitions and recommendations for symbols for the terms used in analytical extraction are presented. Exhaustive, microextraction, elevated temperature, microwave- and ultrasound-assisted, parallel batch, flow through systems, and membrane extraction approaches are discussed. An associated tutorial titled “Extraction” provides a detailed introduction to the topic.
30 citations
TL;DR: This work investigated selective micro-electromembrane extractions of the colored indicators metanil yellow and congo red and the small drug substances nortriptyline, papaverine, mianserin, and citalopram based on their acid-base strength to improve fractionation capability and implement the concept into microfluidic platforms.
21 citations
TL;DR: PALME appeared to be highly efficient for phospholipid removal and qualitative (post-column infusion) and quantitative matrix effects were investigated with fluoxetine, fluvoxamine, and quetiapine as model analytes, and no signs of matrix results were observed.
20 citations
TL;DR: The fully automated EME-LC-MS system offers a significant time saving and in addition demonstrates increased sensitivity as the analytes were automatically enriched during the extraction process as well as concomitantly lower LOD and LOQ.
10 citations
TL;DR: The developed EME-autosampler is a powerful tool for a wide range of applications where high-throughput extractions are required before sample analysis and for demonstrating the potential of known CYP3A4 inhibitors to prevent metabolism of methadone.
Abstract: The current work describes the implementation of electro membrane extraction (EME) into an autosampler for high-throughput analysis of samples by EME-LC–MS. The extraction probe was built into a luer lock adapter connected to a HTC PAL autosampler syringe. As the autosampler drew sample solution, analytes were extracted into the lumen of the extraction probe and transferred to a LC–MS system for further analysis. Various parameters affecting extraction efficacy were investigated including syringe fill strokes, syringe pull up volume, pull up delay and volume in the sample vial. The system was optimized for soft extraction of analytes and high sample throughput. Further, it was demonstrated that by flushing the EME-syringe with acidic wash buffer and reverting the applied electric potential, carry-over between samples can be reduced to below 1%. Performance of the system was characterized (RSD, <10%; R2, 0.994) and finally, the EME-autosampler was used to analyze in vitro conversion of methadone into its m...
8 citations
TL;DR: In this paper, the use of carboxymethyl cellulose sheets as sampling material for dried blood spots was described, where whole blood, spiked with quetiapine, a hydrophobic and basic small molecule drug substance was spotted on the sheet and subsequently dried.
Abstract: This short communication describes the use of carboxymethyl cellulose sheets as sampling material for dried blood spots. Whole blood, spiked with quetiapine, a hydrophobic and basic small molecule drug substance, was spotted on the sheet and subsequently dried. The dried spot was then almost completely dissolved in acidified aqueous solution. It was shown that the dissolved polymer, together with major blood components can easily be precipitated and removed with acetonitrile. The presented sampling on a water-soluble biopolymer derivative followed by precipitation resulted in a simple protocol and around 100 % recovery of the analyte prior to liquid chromatography—tandem mass spectrometry.
5 citations