Alfredo Diaz

Low nanogram per liter determination of halogenated nonylphenols, nonylphenol carboxylates, and their non-halogenated precursors in water and sludge by liquid chromatography electrospray tandem mass spectrometry

A new LC-MS-MS method for quantitative analysis of nonylphenol (NP), nonylphenol carboxylates (NPECs), and their halogenated derivatives: brominated and chlorinated nonylphenols (BrNP, ClNP), brominated and chlorinated nonylphenol carboxylates (BrNPE1C and ClNPE1C) and ethoxycarboxylates (BrNPE2C and ClNPE2C) in water and sludge has been developed. Electrospray negative ionization MS-MS was applied for the identification of above mentioned compounds. Upon collision-induced dissociation, their deprotonated molecules gave different fragments formed by the cleavage of the alkyl moiety and/or (ethoxy)carboxylic moiety. For halogenated compounds a highly diagnostic characteristic pattern of isotopic doublet signals was obtained and fragmentation yielded, in addition to above mentioned ions, [Br]− and [Cl]−, respectively. Quantitative analysis was done in the multiple reaction monitoring (MRM) mode, using two specific combinations of a precursor-product ion transitions for each compound. Additionally, for halogenated compounds two specific channels for each transition reaction, corresponding to two isotopes, were monitored and the ratio of their abundances used as an identification criterion. The method has been validated in terms of sensitivity, selectivity, accuracy, and precision and was applied to the analysis of water and sludge samples from drinking water treatment plant (DWTP) of Barcelona (Catalonia, NE Spain). Halogenated NP and NPECs were detected in prechlorinated water in concentrations up to 315 ng/L, BrNPE2C being the most abundant compound. In the DWTP effluent non-halogenated compounds were detected at trace levels (85, 12 and 10 ng/L for NP, NPE1C, and NPE2C, respectively), whereas concentration of halogenated derivatives never exceeded 10 ng/L. Nonylphenol, brominated and chlorinated NPs were found in flocculation sludge in concentrations of 150, 105, and 145 µg/kg, respectively. Acidic polar metabolites were found in lower concentrations up to 20 µg/kg.

Development of a solid-phase microextraction method for the determination of short-ethoxy-chain nonylphenols and their brominated analogs in raw and treated water

A direct solid-phase microextraction (SPME) procedure has been developed and applied for the simultaneous determination of nonylphenol, nonylphenol mono- and diethoxylates and their brominated derivatives in raw and treated water at low microg l(-1) concentrations. Several parameters affecting the SPME procedure, such as extraction mode (headspace or direct-SPME), selection of the SPME coating, extraction time, addition of organic modifiers such as methanol and temperature were optimized. The divinylbenzene-carboxen-polydimethylsiloxane fiber was the most appropriate one for the determination of nonylphenol ethoxylates (NPEOs) and bromononylphenol ethoxylates (BrNPEOs) by SPME-GC-MS. The optimized method was linear over the range studied (0.11-2.5 microg l(-1)) and showed good precision, with RSD values between 4 and 15% and detection limits ranging from 30 to 150 ng l(-1) depending on the compound. The SPME procedure was compared with a solid-phase extraction-GC-MS method (C18 cartridge) for the analysis of NPEO and BrNPEOs in water samples. There was good agreement between the results from both methods but the SPME procedure showed some advantages such as lower detection limits, a shorter analysis time and the avoidance of organic solvents. The optimized SPME method was applied to determine nonylphenol and brominated metabolites in raw and treated water of Barcelona (NE Spain).

Estrogenic potential of halogenated derivatives of nonylphenol ethoxylates and carboxylates

Halogenated derivatives of nonylphenol and of its alkylates are generated during drinking water disinfection and treatment procedures. In this paper we analyze the potential of these compounds to interact with the estrogen receptor and to activate hormone-regulated gene promoters. We used the recombinant yeast assay (RYA) and the human breast cancer cell MCF7 proliferation assay for both estrogenic and antiestrogenic activities and the enzyme-linked receptor assay to examine in vitro binding to the receptor. Many nonylphenol derivatives were very weak estrogens in our functional tests when compared to nonylphenol while retaining a substantial affinity for the estrogen receptor in vitro. Antiestrogenicity tests demonstrated that brominated nonylphenol and most of the carboxylated compounds studied here behaved as estrogenic antagonists in the RYA. We also detected an increased cytotoxicity for the carboxylated derivatives in both yeast and mammalian cells. We conclude that derivatization may mask the apparent estrogenicity of nonylphenol, but the resulting compounds still represent a potential hazard since they are still able to bind the estrogen receptor and to influence the physiological response to estrogens. Our results also illustrate the advantage of combining different methods to assay estrogenicity of unknown substances.

The behavior of polar aromatic sulfonates during drinking water production: a case study on sulfophenyl carboxylates in two European waterworks.

First investigations are reported on the efficiency of individual purification steps at two waterworks to eliminate sulfophenyl carboxylates (SPC) originating from biodegradation of linear alkylbenzene sulfonate surfactant. The average SPC concentrations in the waters taken from the Llobregat river, Spain and the Rhine river, Germany amounted to 5.0 and 1.8 microg L(-1), respectively. In the Spanish waterworks, neither prechlorination nor flocculation followed by rapid sand filtration had an impact. After ozonation, granular activated carbon filtration, and final chlorination the SPC level was about 2 microg L(-1) in such processed drinking water. In the German waterworks already the rapid sand filtration diminished the SPC concentration by >85%. Subsequent subsoil passage resulted only in a slight elimination, but once again a slow sand filtration prior to the closing chlorination substantially removed the polar micro-pollutants down to a level of <0.05 microg L(-1) SPC.