Solid phase extraction applied to chlorinated phenolics present in the effluent from a pulp mill

Abstract

Solid phase extraction (SPE) using commercial C18 [monofunctional silane —Si(CH3)C18H37] and tC18 [trifunctional silane –SiC18H37] phase cartridges was applied to the analysis of chlorinated phenolic compounds (CPCs) in aqueous effluents from cellulose bleaching processes and the results compared to those obtained by the classical liquid-liquid extraction (LLE) technique. SPE with C18 phase cartridges gave higher recoveries than LLE for eight out of nine standard compounds studied. Quantitative analysis of the CPCs was carried out by capillary gas chromatography with electron capture detection (CGC/ECD) using the internal standard (IS) technique and CGC coupled with a mass selective detector (MSD) was only used for positive identification. The detection limits for ECD were 320.0 μg L–1 for monochlorinated compounds with the exception of 6-chlorovanillin (5.0 μg L–1), and 2.0 μg L–1 for dichlorinated and 1.0 μg L–1 for polychlorinated. The following chlorinated compounds have been identified from a mill effluent: 3,5-dichorophenol, 3,4,6-trichlorophenol, 4,5-dichloroguaiacol, 3,5-dichlorocatechol, 6-chlorovanillin, 4,5-dichlorocatechol, 4,5,6-trichloroguaiacol, 5,6-dichlorovaniline, 3,4,5,6-tetrachlorocatechol, 3,4,5-trichlorosyringol, and 3,4,5,6-tetrachlorocatechol. Toxicity related to pentachlorophenol and the total Toxicity Equivalent Factor (TEF) for each effluent were also determined. The TEF values are higher than the LD50 for pentachlorophenol, indicating a significant toxicity.