title: Isotope pattern deconvolution-tandem mass spectrometry for the determination and confirmation of diclofenac in wastewaters.
abstract: Isotope dilution mass spectrometry (IDMS) based on isotope pattern deconvolution (IPD) has been applied here to MS/MS (QqQ) in order to carry out the quantification and confirmation of organic compounds in complex matrix water samples without the use of a methodological IDMS calibration graph. In this alternative approach, the isotope composition of the spiked sample is measured after fragmentation by SRM and deconvoluted into its constituting components (molar fractions of natural abundance and labeled compound) by multiple linear regression (IPD). The procedure has been evaluated for the determination of the pharmaceutical diclofenac in effluent and influent urban wastewaters and fortified surface waters by UHPLC (ESI) MS/MS using diclofenac-d(4) as labeled compound. Calculations were performed acquiring a part and the whole fragment cluster ion, achieving in all cases recoveries within 90-110% and coefficients of variation below 5% for all water samples tested. In addition, potential false negatives arising from the presence of diclofenac-d(2) impurities in the labeled compound were avoided when the proposed approach was used instead of the most usual IDMS calibration procedure. The number of SRM transitions measured was minimized to three to make possible the application of this alternative technique in routine multi-residue analysis.
authors: Research Institute for Pesticides and Water, Universitat Jaume I, Castelló, Spain.
authors: Angel
authors: A
authors: Castillo
authors: Emma
authors: E
authors: Gracia-Lor
authors: Antoni Francesc
authors: AF
authors: Roig-Navarro
authors: Juan
authors: J
authors: Vicente Sancho
authors: Pablo
authors: P
authors: Rodríguez-González
authors: J Ignacio
authors: JI
authors: García Alonso
mesh_terms: D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D004008:Diclofenac / Q000032:analysis* / Q000592:standards; D007553:Isotope Labeling; D016014:Linear Models; D053719:Tandem Mass Spectrometry / Q000592:standards; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D004008:Diclofenac; D062065:Wastewater; D014867:Water