title: Rapid isolation of angiotensin peptides from plasma by electromembrane extraction.
abstract: The present study has for the first time demonstrated the isolation of peptides from human plasma by electromembrane extraction (EME). Angiotensin 1, angiotensin 2, and angiotensin 3 migrated from 500 microL of diluted plasma, through a thin layer of 1-octanol and 8% di-(2-ethylhexyl) phosphate immobilized as a supported liquid membrane (SLM) in the pores of a porous hollow fiber, and into a 25 microL aqueous acceptor solution present inside the lumen of the fiber. The driving force for the extraction was a 15 V potential difference applied across the SLM. After only 10 min of EME, the peptides were isolated from diluted plasma (pH 3) with extraction recoveries between 25 and 43%. After optimization, the extraction system was evaluated using spiked plasma samples of angiotensin 2. The evaluation was performed by liquid chromatography electrospray mass spectrometry, showing linearity of angiotensin 2 in the range 2.5-125.0 ng/mL (r(2)=0.989), and repeatability (RSD) between 5.6 and 11.6% (n=6). The results demonstrate the possibility of isolating angiotensin peptides from plasma in only 10 min, using electromembrane extraction. The experimental findings are therefore promising with regard to future peptide extractions.
authors.affiliation: Department of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway.
authors.forename: Marte
authors.initials: M
authors.lastname: Balchen
authors.forename: Trine Grønhaug
authors.initials: TG
authors.lastname: Halvorsen
authors.forename: Léon
authors.initials: L
authors.lastname: Reubsaet
authors.forename: Stig
authors.initials: S
authors.lastname: Pedersen-Bjergaard
mesh_terms: D000465:Algorithms; D053000:Analytic Sample Preparation Methods / Q000295:instrumentation / Q000379:methods*; D000806:Angiotensin-Converting Enzyme Inhibitors; D000809:Angiotensins / Q000097:blood* / Q000302:isolation & purification; D005591:Chemical Fractionation / Q000295:instrumentation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D019075:Electrophoresis, Capillary; D006801:Humans; D008567:Membranes, Artificial; D010455:Peptides / Q000097:blood* / Q000302:isolation & purification; D055550:Protein Stability; D015203:Reproducibility of Results; D012997:Solvents; D021241:Spectrometry, Mass, Electrospray Ionization; D013997:Time Factors
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000809:Angiotensins; D008567:Membranes, Artificial; D010455:Peptides; D012997:Solvents