title: Determination of alkylphenols in eluates from pyrolysis solid residues using dispersive liquid-liquid microextraction.
abstract: Dispersive liquid-liquid microextraction (DLLME) coupled with gas chromatography-mass spectrometry (GC-MS) was applied for the determination of 11 alkylphenols in eluates of chars produced in the co-pyrolysis of different wastes. The optimized DLLME procedure, 4 mL of sample solution, 15 microL of trichloroethylene as extraction solvent, 1 mL of acetone as dispersion solvent and addition of 15% (w/v) of NaCl, was validated. Under the optimum conditions, the enrichment factors were in the range of 82-180. Calibration curves were constructed for each analyte in pure water in the concentration range of 0.5-8 microg/L with correlation coefficients higher than 0.999. The limits of detection were between 0.07 and 0.17 microg/L. The repeatability of the method was evaluated using water samples fortified with the analyte mixture at two concentration levels: the relative standard deviation (RSD) values were between 3.7% and 8.0% for a concentration of 0.5 microg/L, and between 4.2% and 6.4% for a concentration of 3 microg/L. The recoveries of the analytes evaluated by fortification of real eluate samples were in the range of 67.9-97.9% for eluate 1 (obtained from a decontaminated char) and in the range of 61.9-101.4% for eluate 2 (obtained from the untreated char). o-Methylphenol presented low recoveries for both eluates showing a possible matrix effect. The results obtained show that this method is adequate for the determination of alkylphenols in environmental aqueous samples and presents itself as a fast and inexpensive technique, using minor amounts of organic solvents.
authors.affiliation: Unidade de Biotecnologia Ambiental (UBia), Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal. maria.b@fct.unl.pt
authors.forename: M
authors.initials: M
authors.lastname: Bernardo
authors.forename: M
authors.initials: M
authors.lastname: Gonçalves
authors.forename: N
authors.initials: N
authors.lastname: Lapa
authors.forename: B
authors.initials: B
authors.lastname: Mendes
mesh_terms: D005591:Chemical Fractionation; D004785:Environmental Pollutants / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D008401:Gas Chromatography-Mass Spectrometry; D019800:Phenol / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D015203:Reproducibility of Results; D012965:Sodium Chloride / Q000737:chemistry; D012997:Solvents / Q000737:chemistry
chemical_list: D004785:Environmental Pollutants; D012997:Solvents; D019800:Phenol; D012965:Sodium Chloride