title: Fully Automated Electro Membrane Extraction Autosampler for LC-MS Systems Allowing Soft Extractions for High-Throughput Applications.
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%; R(2), 0.994) and finally, the EME-autosampler was used to analyze in vitro conversion of methadone into its main metabolite by rat liver microsomes and for demonstrating the potential of known CYP3A4 inhibitors to prevent metabolism of methadone. By making use of the high extraction speed of EME, a complete analytical workflow of purification, separation, and analysis of sample could be achieved within only 5.5 min. With the developed system large sequences of samples could be analyzed in a completely automated manner. This high degree of automation makes the developed EME-autosampler a powerful tool for a wide range of applications where high-throughput extractions are required before sample analysis.
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, 2100 Copenhagen, Denmark.
authors.forename: David
authors.initials: D
authors.lastname: Fuchs
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, 2100 Copenhagen, Denmark.|School of Pharmacy, University of Oslo , P.O. Box 1068 Blindern, 0316 Oslo, Norway.
authors.forename: Stig
authors.initials: S
authors.lastname: Pedersen-Bjergaard
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, 2100 Copenhagen, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Jensen
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, 2100 Copenhagen, Denmark.
authors.forename: Kasper D
authors.initials: KD
authors.lastname: Rand
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, 2100 Copenhagen, Denmark.
authors.forename: Steen
authors.initials: S
authors.lastname: Honoré Hansen
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen , Universitetsparken 2, 2100 Copenhagen, Denmark.
authors.forename: Nickolaj Jacob
authors.initials: NJ
authors.lastname: Petersen