title: Zeolite/iron oxide composite as sorbent for magnetic solid-phase extraction of benzene, toluene, ethylbenzene and xylenes from water samples prior to gas chromatography⬜mass spectrometry.
abstract: This study reports a new composite based on ZSM-5 zeolite decorated with iron oxide magnetic nanoparticles as a valuable sorbent for magnetic solid-phase extraction (MSPE). A proposal is made to determine benzene, toluene, ethylbenzene and xylenes (BTEX) as model analytes in water samples using gas chromatography-mass spectrometry. A two-step multivariate optimization strategy, using Plackett⬜Burman and circumscribed central composite designs, was employed to optimize experimental parameters affecting MSPE. The method was evaluated under optimized extraction conditions (i.e., amount of sorbent, 138mg; extraction time, 11min; sample pH, pH of water (i.e., 5.5⬜6.5); eluent solvent volume, 0.5mL; and elution time, 5min), obtaining a linear response from 1 to 100μgL(↙1) for benzene; from 10 to 100μgL(↙1) for toluene, ethylbenzene and o-xylene; and from 10 to 75μgL(↙1) for m,p-xylene. The repeatability of the proposed method was evaluated at a 40μgL(↙1) spiking level and coefficients of variation ranged between 8 and 11% (n=5). Limits of detection were found to be 0.3μgL(↙1) for benzene and 3μgL(↙1) for the other analytes. These values satisfy the current normative of the Environmental Protection Agency and European Union for BTEX content in waters for human consumption. Finally, drinking water, wastewater and river water were selected as real water samples to assess the applicability of the method. Relative recoveries varied between 85% and 114% showing negligible matrix effects.
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología e Instituto Universitario de Materiales, Universidad de Alicante, P.O. Box 99, E-03080 Alicante, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Fernández
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología e Instituto Universitario de Materiales, Universidad de Alicante, P.O. Box 99, E-03080 Alicante, Spain. Electronic address: lorena.vidal@ua.es.
authors.forename: Lorena
authors.initials: L
authors.lastname: Vidal
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología e Instituto Universitario de Materiales, Universidad de Alicante, P.O. Box 99, E-03080 Alicante, Spain. Electronic address: a.canals@ua.es.
authors.forename: Antonio
authors.initials: A
authors.lastname: Canals
mesh_terms: D000327:Adsorption; D001554:Benzene / Q000302:isolation & purification*; D001555:Benzene Derivatives / Q000302:isolation & purification*; D060766:Drinking Water / Q000737:chemistry; D005062:European Union; D005290:Ferric Compounds / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D057230:Limit of Detection; D058185:Magnetite Nanoparticles / Q000737:chemistry; D045483:Rivers / Q000737:chemistry; D052616:Solid Phase Extraction / Q000379:methods*; D014050:Toluene / Q000302:isolation & purification*; D014481:United States; D014484:United States Environmental Protection Agency; D062065:Wastewater / Q000737:chemistry; D014867:Water / Q000737:chemistry*; D014992:Xylenes / Q000302:isolation & purification*; D017641:Zeolites / Q000737:chemistry*
chemical_list: D001554:Benzene; D001555:Benzene Derivatives; D060766:Drinking Water; D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; D014050:Toluene; D062065:Wastewater; D014867:Water; D014992:Xylenes; D017641:Zeolites; C570564:ZSM-5 zeolite; C000499:ferric oxide; C004912:ethylbenzene
keywords: BTEX; Gas chromatography-mass spectrometry; Magnetic solid-phase extraction; Water samples; ZSM-5 zeolite