A rapid method for determining phenolic endocrine disrupters in water samples
ABSTRACT We have developed a method based on solid-phase extraction coupled on-line to liquid chromatography with UV detection (SPE-HPLC-UV)
to determine bisphenol A and a group of alkylphenols, which have been recognized as endocrine disrupters (ED), in water samples.
We optimized the conditions used for both SPE and the chromatography. The SPE-HPLC-UV method developed is rapid and it enables
routine analysis. Its performance was checked with a variety of aqueous samples collected in the south of Catalonia from the
Ebro river, from the sea, and from tapwater-and waste-water-treatment plants. Drinking water in plastic bottles was also analyzed.
The method enabled determination of ED at low levels; the limits of detection were between 0.01 and 0.1 μg L−1. Bisphenol A and nonylphenol were dttected in some samples.
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ABSTRACT: Nonylphenol ethoxylates (NPEO(x)) are surfactants which are used worldwide and can be transformed in the environment by microorganisms to form nonylphenol (NP). Analysis of these compounds was carried out with micellar electrokinetic capillary chromatography (MEKC). Different parameters such as background electrolyte (BGE) solution, pH, type of surfactant, and sample stacking were optimized. The use of CHES (20 mM, pH 9.1) in combination with 50 mM sodium cholate as a surfactant as BGE solution, together with sample stacking using 50 mM NaCl in the sample and an injection time of 20 s, provided the best separation of the compounds studied. The method was applied to the determination of target analytes in two types of sludge water coming from two steps of a wastewater treatment plant. Liquid-liquid extraction was carried out using toluene as solvent, resulting in recoveries around 100% for all studied analytes. The presence of NPEO(x) was observed in the first step of the sludge water treatment, based on migration time and UV spectra. Identification was confirmed using tandem MS. LOQs of the studied compounds were in the range of 12.7 to 30.8 ng/mL, which is satisfactory for the analysis of real wastewater samples.Journal of Separation Science 07/2009; 32(12):2109-16. · 2.59 Impact Factor
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ABSTRACT: In this article, a solid-phase extraction approach, which takes advantage of the good extraction capabilities of hydrophobic magnetic nanoparticles (MNPs), is presented. The new approach involves the deposition of a thin layer of MNPs in a dedicated stirring unit based on the dual function of a mini-magnet. The system allows the extraction of the analytes in a simple and efficient way. The approach, which reduces the negative effect of the aggregation tendency of hydrophobic MNPs, is characterized for the resolution of a model analytical problem: the determination of some endocrine-disrupting phenols in water by liquid chromatography-photometric detection. All the variables involved in the extraction process have been clearly identified and optimized. The new extraction mode allows the determination of these compounds with limits of detection in the range from 0.15 μg/L (for 4-tert-octylphenol) to 2.7 μg/L (for 4-tert-butylphenol) with a relative standard deviation lower than 5.3 % (for 4-tert-butylphenol).Analytical and Bioanalytical Chemistry 01/2013; · 3.66 Impact Factor
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ABSTRACT: A procedure based on solid-phase microextraction (SPME) and gas chromatography coupled with mass spectrometry (GC-MS) was developed and validated in order to analyse 10 phenols in water samples. The optimised conditions were obtained using polyacrylate fibre (PA), 20ml of sample volume, 10% NaCl, pH 4.0 and direct extraction at 35 degrees C and 1000rpm, for 40min. The linear range and quantification limits for these compounds by SPME-GC-MS were defined. An evaluation of the main uncertainty sources of this method is included, which allows expanded uncertainties in the 9.4-35% range for the majority of the compounds. The main source of uncertainty is associated with matrix effects. The validated method is suitable for monitoring the production and distribution of potable water and was used, in field trials, for the analysis of samples from main intakes of water (surface or underground) and from water supply system of a large area (Lisbon and neighbour municipalities).Chemosphere 07/2007; 68(3):501-10. · 3.14 Impact Factor