Simultaneous Determination of Halogenated Derivatives of Alkylphenol Ethoxylates and Their Metabolites in Sludges, River Sediments, and Surface, Drinking, and Wastewaters by Liquid Chromatography-Mass Spectrometry

A quantitative solid-phase extraction-liquid chromatography/mass spectrometry (SPELC/MS) method is described for the simultaneous analysis of halogenated byproducts of alkylphenolic compounds and their degradation products formed during chlorine disinfection in the presence of bromide ions. Compounds analyzed include brominated and chlorinated nonylphenol ethoxylates (XNPEOs); octylphenol ethoxylates (XOPEOs); nonylphenols (XNP); nonylphenoxycarboxylates (XNPECs) and their precursors nonionic surfactants, alkylphenol ethoxylates (APEOs); and their metabolites formed during sewage treatment, alkylphenoxycarboxylates (APECs) and alkylphenols (APs). Target compounds were concentrated from water samples using a C18 SPE procedure. Extracts were analyzed using reversed phase LC/MS. The performances of both atmospheric pressure chemical ionization (APCI) and electrospray (ESI) interfaces were compared. ESI offered better sensitivity and specificity for a higher range of oligomers. Detection limits (LODs) for water samples were from 20 to 100 ng/L; and for sediment samples, from 2 to 10 g/kg. Slightly higher LODs were obtained for sludge samples (5-25 g/kg). Halogenated byproducts were found in sludge from Barcelona drinking water treatment plant in concentrations of 220 g/kg for BrNP, 430 g/kg for BrNPEOs (nEO = 1 - 2), and 1600 g/kg for BrNPEOs (nEO = 3 - 15). The concentration of ClNPEOs was estimated to be in the order of 660 g/kg (assuming the same response as BrNPEOs). Halogenated OPEOs were also identified, and their concentration was ~50 times lower than the concentration of NPEOs analogues. To our knowledge, this is the first method described that allows simultaneous determination of alkyphenol ethoxylates and halogenated derivatives, including degradation products.