Browsing by Author "Ferreira, Isabel M. P. L. V. O."
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- Fast and Reliable Extraction of Polycyclic Aromatic Hydrocarbons from Grilled and Smoked Muscle FoodsPublication . Silva, Marta; Viegas, Olga; Melo, Armindo; Finteiro, Daniela; Pinho, Olívia; Ferreira, Isabel M. P. L. V. O.A fast and simple method for analysis of 14 PAHs in grilled and smoked muscle foods using acetonitrile based-extraction was validated. The optimum amounts of magnesium sulfate and sodium chloride that promoted phase separation of acetonitrile extract containing PAHs from water phase were selected by Central Composite Design. Matrix-matched calibration curves were constructed by adding different concentrations of PAHs and then subjected to extraction followed by HPLC with fluorescent detection. An excellent linearity for all compounds applying weighed least squares linear regression procedure was achieved. LODs and LOQs were lower than 0.12 and 0.39 ng g−1 respectively. Validation was done according to International Conference on Harmonization recommendations for 14 PAHs. The criteria for 4 EU marker PAHs (benz[a]anthracene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene) established by European Comission Regulation No. 836/2011 was also accomplished. Repeatability and reproducibility were lower than 8 and 13.3%, and the most of recoveries fall in the range of 80–110% in different grilled and smoked muscle foods. The proposed method is a robust tool for determination of PAHs in grilled and smoked muscle foods, being easy to perform in short time.
- Interlaboratory validation of an environmental monitoring method for trace analysis of endocrine disrupting compoundsPublication . Mansilha, Catarina; Rocha, Sonia; Gameiro, Paula; Carina Pinho, Carina; Ferreira, Isabel M. P. L. V. O.; Silva, Poliana; Domingues, ValentinaEnvironmental pollution continues to be an emerging study field, as there are thousands of anthropogenic compounds mixed in the environment whose possible mechanisms of toxicity and physiological outcomes are of great concern. Developing methods to access and prioritize the screening of these compounds at trace levels in order to support regulatory efforts is, therefore, very important. A methodology based on solid phase extraction followed by derivatization and gas chromatography-mass spectrometry analysis was developed for the assessment of four endocrine disrupting compounds (EDCs) in water matrices: bisphenol A, estrone, 17b-estradiol and 17a-ethinylestradiol. The study was performed, simultaneously, by two different laboratories in order to evaluate the robustness of the method and to increase the quality control over its application in routine analysis. Validation was done according to the International Conference on Harmonisation recommendations and other international guidelines with specifications for the GC-MS methodology. Matrix-induced chromatographic response enhancement was avoided by using matrix-standard calibration solutions and heteroscedasticity has been overtaken by a weighted least squares linear regression model application. Consistent evaluation of key analytical parameters such as extraction efficiency, sensitivity, specificity, linearity, limits of detection and quantification, precision, accuracy and robustness was done in accordance with standards established for acceptance. Finally, the application of the optimized method in the assessment of the selected analytes in environmental samples suggested that it is an expedite methodology for routine analysis of EDC residues in water matrices.