title: Matrix solid-phase dispersion followed by liquid chromatography tandem mass spectrometry for the determination of selective ciclooxygenase-2 inhibitors in sewage sludge samples.
abstract: A straightforward single-step extraction method based on matrix solid-phase dispersion (MSPD), followed by high-performance liquid chromatography with hybrid quadrupole time of flight mass spectrometry (LC-QTOF-MS), was developed and optimized to determine five non-steroidal anti-inflammatory drugs (Valdecoxib, Etoricoxib, Parecoxib, Celecoxib and 2,5-Dimethylcelecoxib) in sewage sludge samples. The influence of different operational parameters on the extraction efficiency a well as in the matrix effects of the produced extracts was evaluated in detail. Under final working conditions, freeze dried samples (0.2g) were first soaked with 100μL of aqueous potassium hydroxide solution (60%, w/v), mixed with 1g of anhydrous sodium sulfate and dispersed with 1g of Florisil. This blend was transferred to the top of a polypropylene column cartridge containing 3g of silica. Analytes were recovered using 15mL of hexane/acetone (1:2, v/v) mixture. The extracts were concentrated by evaporation and reconstituted with 1mL of methanol/water (1:1, v/v), filtered and injected in the LC system. Quantification limits from 0.005 and 0.05ngg(-1) and absolute recoveries between 86 and 105% were achieved. Results indicated the presence of two of the targeted COXIBs in real samples of sewage sludge, the highest average concentration (22ngg(-1)) corresponding to celecoxib. Moreover, the screening capabilities of the LC-QTOF-MS system demonstrated that the developed MSPD extraction procedure might be useful for the selective extraction of some other pharmaceuticals (e.g. amiodarone and their metabolite N-desethylamiodarone, miconazole, clotrimazole and ketoprofen) from sludge samples.
authors: Dpto. Química Analítica, Nutrición y Bromatología. Instituto de Investigación y Análisis Alimentario, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors: Sara
authors: S
authors: Triñanes
authors: Dpto. Química Analítica, Nutrición y Bromatología. Instituto de Investigación y Análisis Alimentario, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain. Electronic address: carmela.casais@usc.es.
authors: M Carmen
authors: MC
authors: Casais
authors: Dpto. Química Analítica, Nutrición y Bromatología. Instituto de Investigación y Análisis Alimentario, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors: M Carmen
authors: MC
authors: Mejuto
authors: Dpto. Química Analítica, Nutrición y Bromatología. Instituto de Investigación y Análisis Alimentario, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors: Rafael
authors: R
authors: Cela
mesh_terms: D002851:Chromatography, High Pressure Liquid; D052246:Cyclooxygenase 2 Inhibitors / Q000032:analysis*; D012722:Sewage / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D012722:Sewage
keywords: COX-2 specific inhibitors; Liquid chromatography–quadrupole time-of-flight-mass spectrometry; Matrix solid-phase dispersion; NSAID; Sludge analysis