title: Simultaneous analysis of multiple classes of antimicrobials in environmental water samples using SPE coupled with UHPLC-ESI-MS/MS and isotope dilution.
abstract: A robust and sensitive analytical method was developed for the simultaneous analysis of 21 target antimicrobials in different environmental water samples. Both single SPE and tandem SPE cartridge systems were investigated to simultaneously extract multiple classes of antimicrobials. Experimental results showed that good extraction efficiencies (84.5-105.6%) were observed for the vast majority of the target analytes when extraction was performed using the tandem SPE cartridge (SB+HR-X) system under an extraction pH of 3.0. HPLC-MS/MS parameters were optimized for simultaneous analysis of all the target analytes in a single injection. Quantification of target antimicrobials in water samples was accomplished using 15 isotopically labeled internal standards (ILISs), which allowed the efficient compensation of the losses of target analytes during sample preparation and correction of matrix effects during UHPLC-MS/MS as well as instrument fluctuations in MS/MS signal intensity. Method quantification limit (MQL) for most target analytes based on SPE was below 5ng/L for surface waters, 10ng/L for treated wastewater effluents, and 15ng/L for raw wastewater. The method was successfully applied to detect and quantify the occurrence of the target analytes in raw influent, treated effluent and surface water samples.
authors.affiliation: NUS Environmental Research Institute, National University of Singapore, 5A Engineering Drive 1, T-Lab Building, Singapore 117411, Singapore. Electronic address: eritnh@nus.edu.sg.
authors.forename: Ngoc Han
authors.initials: NH
authors.lastname: Tran
authors.affiliation: Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore.
authors.forename: Hongjie
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore.
authors.forename: Thanh Van
authors.initials: TV
authors.lastname: Do
authors.affiliation: Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore; Department of Civil Environmental Engineering, Stanford University, CA 94305, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Reinhard
authors.affiliation: School of Civil and Environmental Engineering, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia.
authors.forename: Huu Hao
authors.initials: HH
authors.lastname: Ngo
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Yiliang
authors.initials: Y
authors.lastname: He
authors.affiliation: NUS Environmental Research Institute, National University of Singapore, 5A Engineering Drive 1, T-Lab Building, Singapore 117411, Singapore; Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore. Electronic address: ceeginyh@nus.edu.sg.
authors.forename: Karina Yew-Hoong
authors.initials: KY
authors.lastname: Gin
mesh_terms: D000890:Anti-Infective Agents / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D007554:Isotopes / Q000032:analysis; D052616:Solid Phase Extraction; D053719:Tandem Mass Spectrometry; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D000890:Anti-Infective Agents; D007554:Isotopes; D014874:Water Pollutants, Chemical; D014867:Water
keywords: Antibiotics; Antimicrobials; HPLC-MS/MS; Solid phase extraction; Surface water; Wastewater