title: Determination and occurrence of phenoxyacetic acid herbicides and their transformation products in groundwater using ultra high performance liquid chromatography coupled to tandem mass spectrometry.
abstract: A sensitive method was developed and validated for ten phenoxyacetic acid herbicides, six of their main transformation products (TPs) and two benzonitrile TPs in groundwater. The parent compounds mecoprop, mecoprop-p, 2,4-D, dicamba, MCPA, triclopyr, fluroxypr, bromoxynil, bentazone, and 2,3,6-trichlorobenzoic acid (TBA) are included and a selection of their main TPs: phenoxyacetic acid (PAC), 2,4,5-trichloro-phenol (TCP), 4-chloro-2-methylphenol (4C2MP), 2,4-dichlorophenol (DCP), 3,5,6-trichloro-2-pyridinol (T2P), and 3,5-dibromo-4-hydroxybenzoic acid (BrAC), as well as the dichlobenil TPs 2,6-dichlorobenzamide (BAM) and 3,5-dichlorobenzoic acid (DBA) which have never before been determined in Irish groundwater. Water samples were analysed using an efficient ultra-high performance liquid chromatography (UHPLC) method in an 11.9 min separation time prior to detection by tandem mass spectrometry (MS/MS). The limit of detection (LOD) of the method ranged between 0.00008 and 0.0047 µg·L(-1) for the 18 analytes. All compounds could be detected below the permitted limits of 0.1 µg·L(-1) allowed in the European Union (EU) drinking water legislation. The method was validated according to EU protocols laid out in SANCO/10232/2006 with recoveries ranging between 71% and 118% at the spiked concentration level of 0.06 µg·L(-1). The method was successfully applied to 42 groundwater samples collected across several locations in Ireland in March 2012 to reveal that the TPs PAC and 4C2MP were detected just as often as their parent active ingredients (a.i.) in groundwater.
authors.affiliation: Teagasc Environmental Research Centre, Johnstown Castle, Wexford, Ireland. cecoxon@tcd.ie.
authors.forename: Sarah-Louise
authors.initials: SL
authors.lastname: McManus
authors.affiliation: Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland. Mary.Moloney@teagasc.ie.
authors.forename: Mary
authors.initials: M
authors.lastname: Moloney
authors.affiliation: Teagasc Environmental Research Centre, Johnstown Castle, Wexford, Ireland. Karl.Richards@teagasc.ie.
authors.forename: Karl G
authors.initials: KG
authors.lastname: Richards
authors.affiliation: Department of Geology, Trinity College Dublin, Dublin 2, Ireland. cecoxon@tcd.ie.
authors.forename: Catherine E
authors.initials: CE
authors.lastname: Coxon
authors.affiliation: Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland. Martin.Danaher@teagasc.ie.
authors.forename: Martin
authors.initials: M
authors.lastname: Danaher
mesh_terms: D000085:Acetates / Q000032:analysis* / Q000737:chemistry; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D060587:Groundwater / Q000032:analysis / Q000737:chemistry*; D006540:Herbicides / Q000032:analysis* / Q000737:chemistry; D007494:Ireland; D057230:Limit of Detection; D053719:Tandem Mass Spectrometry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D000085:Acetates; D006540:Herbicides; D014874:Water Pollutants, Chemical; C415326:phenoxyacetic acid