title: Selective determination of COXIBs in environmental water samples by mixed-mode solid phase extraction and liquid chromatography quadrupole time-of-flight mass spectrometry.
abstract: The development and performance evaluation of a method for the simultaneous determination of six pharmaceuticals belonging to the class of non-steroidal anti-inflammatory drugs (NSAIDs) which present high selectivity for the cyclooxygenase (COX)-2 isoform of COX (COXIBs) in environmental waters are presented. The method involves an off-line mixed mode (reversed-phase and strong anionic exchange) solid phase extraction (SPE) for the selective concentration of COXIBs in combination with liquid chromatography (LC) quadrupole time-of-flight (QTOF) mass spectrometry (MS). The use of a strong anionic exchange sorbent (Oasis MAX) led to a significant reduction of matrix effects, during electrospray ionization (ESI), in comparison with results obtained for mixed mode weak anionic exchange sorbent (Oasis Wax) and polymeric reversed phase sorbents (Oasis HLB and Strata X). The developed method attained limits of quantification (LOQs) between 0.01 and 0.20 ng L(-1) for river water and effluent wastewater and, for influent wastewater this limits were ranged between 0.03 and 0.45 ng L(-1). Among the pharmaceuticals investigated, two of them (celecoxib and etoricoxib) were detected at low levels (ppt) in real samples of treated and raw wastewaters, and two metabolites were also found; the carboxylated celecoxib and the hydroxylated etoricoxib.
authors.affiliation: Dpto. Química Analítica, Nutrición y Bromatología. Instituto de Investigación y Análisis Alimentario, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: Sara
authors.initials: S
authors.lastname: Triñanes
authors.affiliation: Dpto. Química Analítica, Nutrición y Bromatología. Instituto de Investigación y Análisis Alimentario, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: Maria Carmen
authors.initials: MC
authors.lastname: Casais
authors.affiliation: Dpto. Química Analítica, Nutrición y Bromatología. Instituto de Investigación y Análisis Alimentario, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: Maria Carmen
authors.initials: MC
authors.lastname: Mejuto
authors.affiliation: Dpto. Química Analítica, Nutrición y Bromatología. Instituto de Investigación y Análisis Alimentario, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain. Electronic address: rafael.cela@usc.es.
authors.forename: Rafael
authors.initials: R
authors.lastname: Cela
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D052246:Cyclooxygenase 2 Inhibitors / Q000032:analysis* / Q000302:isolation & purification; D052616:Solid Phase Extraction / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D062065:Wastewater / Q000032:analysis* / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: COX-2 specific inhibitors; COXIBs; Liquid chromatography–tandem mass spectrometry; NSAID; Solid phase extraction; Water and wastewaters