Angelina Pena | Universidade de Coimbra (original) (raw)

Papers by Angelina Pena

Research paper thumbnail of Assessment of pesticide and tetracycline antibiotic residues in honey samples from portugal and spain

Research paper thumbnail of Metodologias analíticas para a determinação de biomarcadores de fumonisinas em amostras biológicas

Research paper thumbnail of Ochratoxin A in food and urine: a nationwide Portuguese two-year study

World Mycotoxin Journal, 2015

Research paper thumbnail of Contents lists available at ScienceDirect

Research paper thumbnail of Ochratoxin A in nephropathic patients from two cities of central zone in Portugal

Journal of Pharmaceutical and Biomedical Analysis, Jun 1, 2007

Research paper thumbnail of Occurrence, profile and spatial distribution of UV-filters and musk fragrances in mussels from Portuguese coastline

Marine Environmental Research, Jul 1, 2018

Research paper thumbnail of Mussels as bioindicators of diclofenac contamination in coastal environments

Environmental Pollution, Jun 1, 2017

Research paper thumbnail of Validation of an Analytical Methodology for Determination of Oxytetracycline and Tetracycline Residues in Honey by HPLC with Fluorescence Detection

Journal of Agricultural and Food Chemistry, Apr 19, 2005

Research paper thumbnail of Novel IAC-LC–ESI-MS2 analytical set-up for ochratoxin A determination in pork

Food Chemistry, Jun 1, 2013

Research paper thumbnail of Determinants of ochratoxin A exposure—A one year follow-up study of urine levels

International Journal of Hygiene and Environmental Health, Apr 1, 2012

Research paper thumbnail of Determination of fluoroquinolone antibiotics in wastewater using ultra high-performance liquid chromatography with mass spectrometry and fluorescence detection

Journal of Separation Science, Jun 15, 2010

Research paper thumbnail of The potential of citrus by-products in the development of functional food and active packaging

Advances in food and nutrition research, 2023

Research paper thumbnail of By-products of dates, cherries, plums and artichokes: A source of valuable bioactive compounds

Trends in Food Science and Technology, 2023

Research paper thumbnail of Determination of Tetracycline Antibiotics in Salmon Muscle by Liquid Chromatography Using Post-Column Derivatization with Fluorescence Detection

Journal of AOAC International, Sep 1, 2003

Research paper thumbnail of Determination of organochlorine pesticide residues in honey from the central zone of Portugal and the Valencian community of Spain

Journal of Chromatography A, Sep 1, 2004

Research paper thumbnail of Dispersive liquid–liquid microextraction followed by microwave-assisted silylation and gas chromatography-mass spectrometry analysis for simultaneous trace quantification of bisphenol A and 13 ultraviolet filters in wastewaters

Journal of Chromatography A, Oct 1, 2015

A novel multi-residue gas chromatography-mass spectrometry (GC-MS) method was validated for the s... more A novel multi-residue gas chromatography-mass spectrometry (GC-MS) method was validated for the simultaneous determination of trace levels (ng/L) of 13 UV-filters and bisphenol A (BPA) in wastewater samples. It was based on dispersive liquid-liquid microextraction (DLMME) followed by rapid microwave-assisted silylation of the analytes. Several parameters of both extraction and derivatization steps such as type of extractive and dispersive solvents, solvent volumes, pH, salt addition, time and power of microwave were evaluated to achieve the highest yield and to attain the lowest detection limits. Optimized DLLME consisted in the formation of a cloudy solution promoted by the fast addition to the sample (10mL) of a mixture of tetrachloroethylene (50μL, extraction solvent) in acetone (1mL, dispersive solvent). The sedimented phase obtained was evaporated and further silylated under the irradiation of 600W microwave for 5min, being the derivatization yields similar to those obtained after a conventional heating process for 30min at 75°C. Limits of detection and quantification of the method using real samples were 2ng/L and 10ng/L, respectively. Mean extraction efficiency of 82% for three concentrations were achieved, supporting the accuracy of the method. Intra-day and inter-day repeatability of measurements (expressed as relative standard deviation) were lower than 22%. The method was successfully applied to the determination of UV-filters and BPA in samples collected from 15 wastewater treatment plants (WWTPs) in Portugal. Eight analytes were detected, among which 2-hydroxy-4-methoxybenzophenone, 2-ethylhexyl-4-(dimethylamino)benzoate, octocrylene, and BPA were consistently found in the three seasons of collection.

Research paper thumbnail of Occurrence of caffeine, saccharin, benzoic acid and sorbic acid in soft drinks and nectars in Portugal and subsequent exposure assessment

Food Chemistry, Jul 1, 2010

ABSTRACT A reliable method for the determination of benzoic and sorbic acids, caffeine and saccha... more ABSTRACT A reliable method for the determination of benzoic and sorbic acids, caffeine and saccharin in soft drink and nectars using high performance liquid chromatography and UV detection was validated. The chromatographic separation was achieved with a C18 column (250 × 4.6 mm) and one buffered mobile phase, KH2PO4 0.02 M/ACN (90:10)/phosphoric acid at pH 4.2. The effluent was monitored at 220 nm.Benzoic acid was detected in 19 soft drinks, being 11 traditional soft drinks and 8 based on mineral water, with mean concentrations of 158 and 148 mg/L, respectively. Fifteen samples, 7 traditional and 8 based on mineral water, contained sorbic acid, with mean concentrations of 172 and 188 mg/L, respectively.Saccharin and caffeine were not detected in soft drinks based on mineral waters. In contrast, 6 samples of traditional drinks contained both additives, with mean levels of 75 and 97 mg/L, respectively. The four additives were not detected in nectar samples.According to European Union and Portuguese legislation, the maximum permitted level (MPL) for benzoic acid was exceeded in 10 soft drinks, and the MPL for sorbic acid overlapped in 3 samples of the referred samples. Two samples exceeded the MPL for the sum of both preservatives, and in 1 sample the MPL for saccharin was overlapped.The estimated daily intakes (EDI) of benzoic, sorbic acid, and saccharin for the average consumer were below the acceptable daily intakes (ADIs). For benzoic acid, the EDIs were 0.25 and 0.32 mg/kg b.w./day, representing 4.9%, and 6.4% of the ADI, respectively for traditional soft drinks and soft drinks based on mineral water. A similar situation was observed for sorbic acid. In this way, the EDIs were 0.17 and 0.41 mg/kg b.w./day, representing only 0.68% and 1.6% of the ADI for the same kind of drinks. For saccharin, the EDI represents 1.28% of the ADI. The EDI for caffeine was 0.08 mg/kg b.w./day.

Research paper thumbnail of Determination of chlorophenoxy herbicides in waters by capillary gas chromatography with ion trap detection

Journal of Chromatography A, 1997

Research paper thumbnail of Development and Validation of an Analytical Method Based on Quechers Followed by Uhplc-Tof-Ms for the Determination of Tropane Alkaloids in Buckwheat and Buckwheat Products

Research paper thumbnail of Effect of packaging strategy on the shelf life of meat

Alimentación, Equipos y Tecnología, 2010

Research paper thumbnail of Assessment of pesticide and tetracycline antibiotic residues in honey samples from portugal and spain

Research paper thumbnail of Metodologias analíticas para a determinação de biomarcadores de fumonisinas em amostras biológicas

Research paper thumbnail of Ochratoxin A in food and urine: a nationwide Portuguese two-year study

World Mycotoxin Journal, 2015

Research paper thumbnail of Contents lists available at ScienceDirect

Research paper thumbnail of Ochratoxin A in nephropathic patients from two cities of central zone in Portugal

Journal of Pharmaceutical and Biomedical Analysis, Jun 1, 2007

Research paper thumbnail of Occurrence, profile and spatial distribution of UV-filters and musk fragrances in mussels from Portuguese coastline

Marine Environmental Research, Jul 1, 2018

Research paper thumbnail of Mussels as bioindicators of diclofenac contamination in coastal environments

Environmental Pollution, Jun 1, 2017

Research paper thumbnail of Validation of an Analytical Methodology for Determination of Oxytetracycline and Tetracycline Residues in Honey by HPLC with Fluorescence Detection

Journal of Agricultural and Food Chemistry, Apr 19, 2005

Research paper thumbnail of Novel IAC-LC–ESI-MS2 analytical set-up for ochratoxin A determination in pork

Food Chemistry, Jun 1, 2013

Research paper thumbnail of Determinants of ochratoxin A exposure—A one year follow-up study of urine levels

International Journal of Hygiene and Environmental Health, Apr 1, 2012

Research paper thumbnail of Determination of fluoroquinolone antibiotics in wastewater using ultra high-performance liquid chromatography with mass spectrometry and fluorescence detection

Journal of Separation Science, Jun 15, 2010

Research paper thumbnail of The potential of citrus by-products in the development of functional food and active packaging

Advances in food and nutrition research, 2023

Research paper thumbnail of By-products of dates, cherries, plums and artichokes: A source of valuable bioactive compounds

Trends in Food Science and Technology, 2023

Research paper thumbnail of Determination of Tetracycline Antibiotics in Salmon Muscle by Liquid Chromatography Using Post-Column Derivatization with Fluorescence Detection

Journal of AOAC International, Sep 1, 2003

Research paper thumbnail of Determination of organochlorine pesticide residues in honey from the central zone of Portugal and the Valencian community of Spain

Journal of Chromatography A, Sep 1, 2004

Research paper thumbnail of Dispersive liquid–liquid microextraction followed by microwave-assisted silylation and gas chromatography-mass spectrometry analysis for simultaneous trace quantification of bisphenol A and 13 ultraviolet filters in wastewaters

Journal of Chromatography A, Oct 1, 2015

A novel multi-residue gas chromatography-mass spectrometry (GC-MS) method was validated for the s... more A novel multi-residue gas chromatography-mass spectrometry (GC-MS) method was validated for the simultaneous determination of trace levels (ng/L) of 13 UV-filters and bisphenol A (BPA) in wastewater samples. It was based on dispersive liquid-liquid microextraction (DLMME) followed by rapid microwave-assisted silylation of the analytes. Several parameters of both extraction and derivatization steps such as type of extractive and dispersive solvents, solvent volumes, pH, salt addition, time and power of microwave were evaluated to achieve the highest yield and to attain the lowest detection limits. Optimized DLLME consisted in the formation of a cloudy solution promoted by the fast addition to the sample (10mL) of a mixture of tetrachloroethylene (50μL, extraction solvent) in acetone (1mL, dispersive solvent). The sedimented phase obtained was evaporated and further silylated under the irradiation of 600W microwave for 5min, being the derivatization yields similar to those obtained after a conventional heating process for 30min at 75°C. Limits of detection and quantification of the method using real samples were 2ng/L and 10ng/L, respectively. Mean extraction efficiency of 82% for three concentrations were achieved, supporting the accuracy of the method. Intra-day and inter-day repeatability of measurements (expressed as relative standard deviation) were lower than 22%. The method was successfully applied to the determination of UV-filters and BPA in samples collected from 15 wastewater treatment plants (WWTPs) in Portugal. Eight analytes were detected, among which 2-hydroxy-4-methoxybenzophenone, 2-ethylhexyl-4-(dimethylamino)benzoate, octocrylene, and BPA were consistently found in the three seasons of collection.

Research paper thumbnail of Occurrence of caffeine, saccharin, benzoic acid and sorbic acid in soft drinks and nectars in Portugal and subsequent exposure assessment

Food Chemistry, Jul 1, 2010

ABSTRACT A reliable method for the determination of benzoic and sorbic acids, caffeine and saccha... more ABSTRACT A reliable method for the determination of benzoic and sorbic acids, caffeine and saccharin in soft drink and nectars using high performance liquid chromatography and UV detection was validated. The chromatographic separation was achieved with a C18 column (250 × 4.6 mm) and one buffered mobile phase, KH2PO4 0.02 M/ACN (90:10)/phosphoric acid at pH 4.2. The effluent was monitored at 220 nm.Benzoic acid was detected in 19 soft drinks, being 11 traditional soft drinks and 8 based on mineral water, with mean concentrations of 158 and 148 mg/L, respectively. Fifteen samples, 7 traditional and 8 based on mineral water, contained sorbic acid, with mean concentrations of 172 and 188 mg/L, respectively.Saccharin and caffeine were not detected in soft drinks based on mineral waters. In contrast, 6 samples of traditional drinks contained both additives, with mean levels of 75 and 97 mg/L, respectively. The four additives were not detected in nectar samples.According to European Union and Portuguese legislation, the maximum permitted level (MPL) for benzoic acid was exceeded in 10 soft drinks, and the MPL for sorbic acid overlapped in 3 samples of the referred samples. Two samples exceeded the MPL for the sum of both preservatives, and in 1 sample the MPL for saccharin was overlapped.The estimated daily intakes (EDI) of benzoic, sorbic acid, and saccharin for the average consumer were below the acceptable daily intakes (ADIs). For benzoic acid, the EDIs were 0.25 and 0.32 mg/kg b.w./day, representing 4.9%, and 6.4% of the ADI, respectively for traditional soft drinks and soft drinks based on mineral water. A similar situation was observed for sorbic acid. In this way, the EDIs were 0.17 and 0.41 mg/kg b.w./day, representing only 0.68% and 1.6% of the ADI for the same kind of drinks. For saccharin, the EDI represents 1.28% of the ADI. The EDI for caffeine was 0.08 mg/kg b.w./day.

Research paper thumbnail of Determination of chlorophenoxy herbicides in waters by capillary gas chromatography with ion trap detection

Journal of Chromatography A, 1997

Research paper thumbnail of Development and Validation of an Analytical Method Based on Quechers Followed by Uhplc-Tof-Ms for the Determination of Tropane Alkaloids in Buckwheat and Buckwheat Products

Research paper thumbnail of Effect of packaging strategy on the shelf life of meat

Alimentación, Equipos y Tecnología, 2010