Nuno Lapa

Citation:

Bernardo, M., M. Gonçalves, N. Lapa, and B. Mendes. "Determination of alkylphenols in eluates from pyrolysis solid residues using dispersive liquid-liquid microextraction." Chemosphere. 79.11 (2010): 1026-1032.

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 μL 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 μg/L with correlation coefficients higher than 0.999. The limits of detection were between 0.07 and 0.17 μg/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 μg/L, and between 4.2% and 6.4% for a concentration of 3 μg/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.

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