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A multiresidue method for screening endocrine-disrupting chemicals (EDCs) and pharmaceuticals in aqueous samples is presented. Four 10-mL aliquots of water were taken for stir bar sorptive extraction (SBSE) and they were treated in the following way. In sample one, in situ derivatization was performed with acetic acid anhydride to improve the extraction efficiencies and chromatographic analysis of phenolic compounds. For the same reasons, aliquot two was treated with ethyl chloroformate to improve amine and acid extraction and analysis, and aliquot three with tetraethylborate to enhance organotin compound extraction and analysis. Methanol was added to sample four to stop adsorption of apolar solutes on the wall. After SBSE, the four stir bars, together with a plug of glass wool impregnated with bis(trimethylylsilyl)trifluoroacetamide (BSTFA) to derivatize hydroxyl functionalities, were introduced into the same thermal desorption tube, heat-desorbed, and analyzed simultaneously by capillary GC/MS. The figures of merit of the method were evaluated with an EDC model mixture. In scan-mode MS, the limits of detection (LODs) were in the range 1-500 ng/L, while the LODs dropped by a factor of 50-100 when ion monitoring MS was applied to the targets. The performance of the method was illustrated by analysing some real-world water samples.

A cross-linked methacrylate molecularly imprinted polymer (poly-4-vinylpyridine-co-trimethylolpropane-trimethacrylate) selective for bisphenol A (BPA) was synthesized, using a fluorinated BPA derivative (4,4'-(hexafluoroisopropylidene)-diphenol) as a mimic template, and applied to the analysis of real-world samples of process and potable waters. The molecularly imprinted polymer also showed a high affinity and selectivity for 17-beta-estradiol and ethynylestradiol. A method to analyze BPA, 17-beta-estradiol, and ethynylestradiol at ultratrace levels was thus developed from a screening procedure to monitor endocrine-disrupting chemicals in water samples. The method consists of the BPA-selective cleanup by molecularly imprinted SPE using cartridges packed with the polymer developed, its recovery by stir bar sorptive extraction after ad hoc derivatization to obtain the corresponding BPA-acetate, and its analysis by GC-time window-SIM-MS after online thermal desorption. The method showed good linearity in the working range (R(2)=0.9969), high repeatability (RSD% <10.1), recoveries always above 90%, and very low LOD (10 pg/L) and LOQ (1 ng/L) and can easily be extended to the determination of 17-beta-estradiol and ethynylestradiol ultratraces. The method's effectiveness was evaluated by analyzing the real-world water samples; it enabled preconcentration and detection of BPA at ultratrace levels.

The present study is focused on flavan-3-ols characterizing the antioxidant properties of fermented tea (Camellia sinensis). These bioactive compounds, object of nutritional claims in commercial products, should be quantified with rigorous analytical procedures whose accuracy and precision have been stated with a certain level of confidence. An HPLC-UV/ DAD method, able to detect and quantify flavan-3-ols in infusions and ready-to-drink teas, has been developed for routine analysis and validated by characterizing several performance parameters. The accuracy assessment has been run through a series of LC-MS/MS analyses. Epigallocatechin, (1)-catechin, (À)-epigallocatechingallate, (À)-epicatechin, (À)-gallocatechingallate, (À)-epicatechingallate, and (À)-catechingallate were chosen as markers of the polyphenolic fraction. Quantitative results showed that samples obtained from tea leaves infusion were richer in polyphenolic antioxidants than those obtained through other industrial processes. The influence of shelf-life and packaging material on the flavan-3-ols content was also considered; markers decreased, with an exponential trend, as a function of time within the shelf life while packaging materials demonstrated to influence differently the flavan-3-ol fraction composition over time. The method presented here provides quantitative results with a certain level of confidence and is suitable for a routine quality control of iced teas whose antioxidant properties are object of nutritional claim.

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