title: Direct aqueous supercritical fluid extraction coupled on-line with liquid chromatography-tandem mass spectrometry for the analysis of polyether ionophore antibiotics in water.
abstract: A direct aqueous SFE system designed to extract water samples contained in vials has been coupled on-line with a reverse phase LC-MS-MS system using a single 10-port valve. An SFE trap system using C(1) stationary phase connected to a C(18) analytical HPLC column enabled the SFE-LC-MS-MS analysis of three polyether ionophore antibiotics in water using a step gradient. A quantitative SFE-LC-MS-MS method has been developed whereby the progress of SFE can be monitored directly on-line such that ionophore recovery profile data from a single water sample can be obtained. Using a continuous direct aqueous SFE period of 75 min, the SFE-LC-MS-MS recoveries of the ionophores were: monensin 76.2% with RSD 4.1%, lasalocid 84.6% with RSD 3.8% and narasin 91.2% with RSD 3.2%. With positive ion electrospray ionization, the SFE-LC-MS-MS system using a 4 mL water sample provided multiple reaction monitoring (MRM) limits of detection for monensin and lasalocid each equivalent to 90 ng/L whereas 30 ng/L for narasin. A two-way valve controlling carbon dioxide distribution to the SFE vessel has provided a means for the initial investigation of the recovery of ionophore sodium salts from water using static SFE.
authors.affiliation: School of Chemical Engineering, University of Science and Technology Liaoning, 185 Qianshan Zhong Road, Anshan 114051, Liaoning Province, China. syphir1000@gmail.com
authors.forename: Edward D
authors.initials: ED
authors.lastname: Ramsey
authors.forename: Anthony T
authors.initials: AT
authors.lastname: Rees
authors.forename: Guo
authors.initials: G
authors.lastname: Wei
authors.forename: Jing Y
authors.initials: JY
authors.lastname: Liu
authors.forename: Xiu H
authors.initials: XH
authors.lastname: Wu
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000737:chemistry; D002853:Chromatography, Liquid / Q000379:methods*; D025924:Chromatography, Supercritical Fluid / Q000379:methods*; D007476:Ionophores / Q000032:analysis* / Q000737:chemistry; D015394:Molecular Structure; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D007476:Ionophores; D014874:Water Pollutants, Chemical