RISK ASSESSMENT OF DISINFECTION BY-PRODUCTS IN DRINKING WATER: OCCURRENCE, EVALUATION AND CONTROL

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Dispersive Liquid–Liquid Microextraction for the Simultaneous Determination of Parent and Nitrated Polycyclic Aromatic Hydrocarbons in Water Samples

Publication . Borges, Bárbara; Melo, Armindo; Ferreira, Isabel M.P.L.V.O.; Mansilha, Catarina

A new method for simultaneous extraction and quantification of 6 nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) and 16 parent polycyclic aromatic hydrocarbons (PAHs) in water matrices was optimized and validated. The extraction procedure was based on dispersive liquid-liquid microextraction technique, followed by gas chromatography-mass detection. The optimum conditions of extraction (volume of the extraction solvent, dispersive solvents and amount of salt) were selected using central composite design. The best results were found by using 200 μL of acetonitrile as dispersive solvent, 60 μL of chloroform as extraction solvent, and 10% (w/v) NaCl. Excellent linearity was observed in the range of 10–150 ng L−1 with correlation coefficients (r2) ranging between 0.9996 and 0.9999 for nitro-PAHs and in the range of 5–150 ng L−1 with r2 ranging from 0.9998 to 1.000 for PAHs. The limits of detection for the nitro-PAHs studied ranged from 0.82 to 3.37 ng L−1, whereas for PAHs ranged from 0.62 to 3.48 ng L−1. The intra- and inter-day precisions for nitro-PAHs were in the range of 0.45 to 19.54% and 0.43 to 19.62%, respectively, and for PAHs ranged between 0.45 to 17.42% and 0.38 to 18.97%, respectively. The proposed method was successfully applied in analyses of groundwater, sea, rain water and river water, being appropriate for routine analyses.

2017-05-17Journal article

Open access

The Use of Feathers from Racing Pigeons for Doping Control Purposes

Publication . Moreira, Fernando X.; Carmo, Helena; Melo, Armindo; André, Maria B.; Silva, Renata; Azevedo, Zélia; Bastos, Maria L.; de Pinho, Paula G.

The development of accurate and reliable analytical methodologies to detect the abuse of doping agents in sport animals is crucial to ensure their welfare, as well as to support continuing social acceptance of these sports. The detection of doping agents in racing pigeons is difficult, especially owing to the disadvantages and limitations of obtaining samples from conventional matrices. The present study aimed to develop and validate an analytical methodology combining a two-step extraction procedure (liquid-liquid extraction and solid-phase extraction) in feathers from racing pigeons with analysis by liquid chromatography tandem mass spectrometry (LC-MS-MS) that enabled the simultaneous detection of a beta-agonist drug (clenbuterol) and three corticosteroids (prednisolone, betamethasone and budesonide). The method was validated concerning linearity (with coefficients of determination always higher than 0.99), accuracy (87.3-112.4%), precision (repeatability and intermediate precision coefficient of variation (CV%) always below 15%), recovery (71.6-98.2%), limits of detection (0.24-0.52 ng/g) and quantification (0.79 and 0. 1.74 ng/g) and specificity. The applicability of the method was performed using feathers from pigeons administered orally with a daily dose of 0.075 mg of betamethasone. The drug was administered during 60 days and successive analyses of feathers were performed, at the end of the administration protocol and also after ceasing the oral administration of the drug, for a three weeks period.

2018-12-15Journal article

Restricted access

Modeling of α-acids and xanthohumol extraction in dry-hopped beers

Publication . Machado, Júlio C.; Faria, Miguel A.; Melo, Armindo; Martins, Zita E.; Ferreira, Isabel M.P.L.V.O.

The practice of dry-hopping has been used by the brewing industry to obtain beers with increased contents of flavor and bitterness compounds. Notwithstanding this, other compounds such as α-acids (AA) and xhanthohumol (XN) are co-extracted influencing the final characteristics of the beer, particularly its beneficial bioactivity. In this context a model for the understanding of AA and XN extraction by dry-hopping is proposed. The varieties Chinook (CHI), East Kent Goldings (EKG) and Tettnanger (TET) were assayed and robust statistical approaches were applied for data interpretation. Concentration of AA in beers post-maturation reached values higher than 20 mg/L using 2.8 g/L of CHI hops and 10 days of maturation. For XN, a similar behavior was verified. The maximum efficiency of AA and XN extraction (transfer rate) were reached at 13.5 days with dose rates of 147 and 13.9 mg/L, respectively.

2018-11-10Journal article

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Fast and Reliable Extraction of Polycyclic Aromatic Hydrocarbons from Grilled and Smoked Muscle Foods

Publication . 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.

2018-07-17Journal article

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Acute and chronic toxicity assessment of haloacetic acids using Daphnia magna

Publication . Melo, Armindo; Ferreira, Cláudia; Ferreira, Isabel M.P.L.V.O.; Mansilha, Catarina

Haloacetic acids (HAAs) are undesirable disinfection by-products (DBPs), released into aquatic ecosystems from various anthropogenic and natural sources. The aim of this study was to examine the ecological risk of exposure to three HAAs commonly detected in water, such as monobromoacetic acid (MBA), monochloroacetic acid (MCA), and trichloroacetic acid (TCA), in in vivo acute and chronic toxicity tests using Daphnia magna as a model. Acute tests showed that MBA was the most toxic of these compounds followed by MCA and TCA as evidenced by immobilization. Aquatic organisms in natural conditions might be exposed simultaneously to numerous compounds; thus, binary mixtures of selected HAAs and a ternary mixture of these were tested. Concentration addition (CA) and independent action (IA) models were used for a predictive assessment of mixture toxicity. Data demonstrated that CA appeared to be the most reliable indicator for HAAs binary and ternary mixtures suggestive of an additive behavior. Median effective concentration (EC50) values from the mixed exposure tests were significantly lower than results obtained from single tests for all three HAAs where an increase of toxicity greater than 50%. Multigenerational chronic tests were also performed exposing daphnids to the ternary mixture of HAAs. A markedly decreased sexual maturity and number of offspring and broods per daphnid especially in the second generation were noted.

2019-10-12Journal article

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