title: Applicability of solid-phase microextraction followed by on-fiber silylation for the determination of estrogens in water samples by gas chromatography-tandem mass spectrometry.
abstract: A solvent-free method for the determination of five estrogens in water samples at the low ng/l was optimized. Compounds were first concentrated on a polyacrylate (PA) solid-phase microextraction (SPME) fiber, directly exposed to the water sample, and then on-fiber silylated on the headspace of a vial containing 50 microl of N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA). Derivatized analytes were determined using GC with MS/MS detection. Influence of several factors on the efficiency of the microextraction step (e.g. time, sample volume, pH, ionic strength and fiber coating) is systematically described. Derivatization conditions were optimized in order to achieve the complete silylation of all hydroxyl groups contained in the structure of the compounds. Detection limits (from 0.2 to 3 ng/l) are compared with those obtained using the same detection technique and different sample preparation strategies, such as solid-phase extraction followed by silylation of the analytes in the organic extract and SPME without derivatization. The method was applied to the analysis of sewage water samples. Two of the investigated species were detected above the quantification limits of the procedure.
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología, Instituto de Investigación y Análisis Alimentario, Universidad de Santiago de Compostela, Santiago de Compostela 15782, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Carpinteiro
authors.forename: J B
authors.initials: JB
authors.lastname: Quintana
authors.forename: I
authors.initials: I
authors.lastname: Rodríguez
authors.forename: A M
authors.initials: AM
authors.lastname: Carro
authors.forename: R A
authors.initials: RA
authors.lastname: Lorenzo
authors.forename: R
authors.initials: R
authors.lastname: Cela
mesh_terms: D004967:Estrogens / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D019158:N-Acetylneuraminic Acid / Q000032:analysis*; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D004967:Estrogens; D014874:Water Pollutants, Chemical; D012965:Sodium Chloride; D019158:N-Acetylneuraminic Acid