title: In situ aqueous derivatization and determination of non-steroidal anti-inflammatory drugs by salting-out-assisted liquid-liquid extraction and gas chromatography-mass spectrometry.
abstract: A new analytical method for the determination of trace levels of five non-steroidal anti-inflammatory drugs (NSAIDs: clofibric acid, ibuprofen, naproxen, diclofenac and ketoprofen) in water samples is described. The analytical procedure involves in situ aqueous derivatization with N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and 2,2,2-trifluoroethylamine hydrochloride (TFEA) and salting-out liquid-liquid extraction (SALLE), followed by gas chromatography-programmed temperature vaporizer-mass spectrometry (GC-PTV-MS). The influence of several parameters on the efficiency of the derivatization (stirring time, reaction time, reagent concentration and pH), and the extraction (solvent, volume, salts and stirring time) and injection steps (liner, injection volume, liner temperature, injection time, venting time and venting flow) was investigated. The detection limits of the method in water varied from 0.042 μg/L for ibuprofen to 1.2 μg/L for ketoprofen. The relative standard deviations (RSD) values were found to be relatively low (<10% for all compounds). The methodology developed was applied to the determination of NSAIDs in several environmental matrices including tap, river, sea and influent and effluent waste water samples. The results obtained show the presence of ibuprofen and naproxen in the influent waste water sample.
authors.affiliation: Departamento de Química Analítica, Facultade de Ciencias, Universidade da Coruña, Campus da Zapateira s/n, E-15071 A Coruña, Spain.
authors.forename: Gloria Grueiro
authors.initials: GG
authors.lastname: Noche
authors.forename: María Esther Fernández
authors.initials: ME
authors.lastname: Laespada
authors.forename: José Luis Pérez
authors.initials: JL
authors.lastname: Pavón
authors.forename: Bernardo Moreno
authors.initials: BM
authors.lastname: Cordero
authors.forename: Soledad Muniategui
authors.initials: SM
authors.lastname: Lorenzo
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000032:analysis / Q000302:isolation & purification*; D005591:Chemical Fractionation / Q000379:methods*; D005021:Ethylamines / Q000737:chemistry; D005022:Ethyldimethylaminopropyl Carbodiimide / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000302:isolation & purification
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D005021:Ethylamines; D014874:Water Pollutants, Chemical; C032626:trifluoroethylamine; D012965:Sodium Chloride; D005022:Ethyldimethylaminopropyl Carbodiimide