title: Analysis of a basic drug by on-line solid-phase extraction liquid chromatography/tandem mass spectrometry using a mixed mode sorbent.
abstract: Two on-line configurations using multiple 6- and 10-port valves were investigated for high-flow on-line extraction of a basic drug in rat plasma and human urine using a reversed-phase and a cation-exchange SPE sorbent. The first configuration studied was a single reversed-phase extraction cartridge (2.1 x 20 mm, 25 microm) using an optimized washing protocol. The results showed that up to 1.5 mL of sample (urine or plasma diluted 1:1) can be injected with limits of quantification (LOQs) as low as 100 pg/mL. The second configuration studied was the combination of a cation exchanger and a reversed-phase cartridge using at-column dilution. The results showed better LOQs than those obtained with the single cartridge at 10 pg/mL with the same injection volume. The mass spectrometer was operated in the multiple reaction monitoring (MRM) mode. All calibration curves gave an average of 5% relative standard deviation (RSD).
authors.affiliation: Waters Corporation, 34 Maple St., Milford, MA 01757-3696, USA. claude_mallet@waters.com
authors.forename: Claude R
authors.initials: CR
authors.lastname: Mallet
authors.forename: Ziling
authors.initials: Z
authors.lastname: Lu
authors.forename: Jeff
authors.initials: J
authors.lastname: Mazzeo
authors.forename: Uwe
authors.initials: U
authors.lastname: Neue
mesh_terms: D000042:Absorption; D000319:Adrenergic beta-Antagonists / Q000032:analysis / Q000097:blood / Q000652:urine; D000818:Animals; D002853:Chromatography, Liquid; D006801:Humans; D007202:Indicators and Reagents; D013058:Mass Spectrometry; D004364:Pharmaceutical Preparations / Q000032:analysis*; D011433:Propranolol / Q000032:analysis / Q000097:blood / Q000652:urine; D051381:Rats; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000319:Adrenergic beta-Antagonists; D007202:Indicators and Reagents; D004364:Pharmaceutical Preparations; D011433:Propranolol