Browsing by Author "Nunes, Maria J. M."
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- Evaluating the effectiveness of four preservatives in enhancing the shelf life and safety of meat analoguesPublication . Nunes, Maria J. M.; Escobar, Luis; Noronha, Lúcia; Cruz, Inês; Komora, Norton; Barbosa, Joana; Carvalho, Fátima; Teixeira, Paula
- Impact of nitrite reduction on the microbiological safety of cooked pork hamPublication . Nunes, Maria J. M.; Noronha, Lúcia; Cruz, Inês; Komora, Norton; Pereira, Rui; Barbosa, Joana; Carvalho, Fátima; Teixeira, Paula
- Impact of nitrite reduction on the technological evaluation of cooked porked hamPublication . Nunes, Maria J. M.; Noronha, Lúcia; Cruz, Inês; Komora, Norton; Barbosa, Joana; Carvalho, Fátima; Teixeira, Paula
- Multiparametric sequential injection system for the determination of nutrients in soil leachatesPublication . Nunes, Maria J. M.; Mesquita, Raquel B. R.; Ribas, Tânia C. F.; Rangel, António O. S. S.
- Redução dos nitritos em produtos de charcutaria: uma “alternativa” saudável e segura?Publication . Nunes, Maria J. M.; Noronha, Lúcia; Cruz, Inês; Carvalho, Fátima; Teixeira, Paula
- Sequential injection method for bi-parametric determination of iron and manganese in soil leachatesPublication . Mesquita, Raquel B. R.; Moniz, Tânia; Nunes, Maria J. M.; Mesquita, Letícia S.; Rangel, Maria; Rangel, António O. S. S.The aim of this work was to develop a sequential injection (SI) method for the determination of the micronutrients iron and manganese, in soil leachates, as a tool to assess potential groundwater contamination. The described sequential injection method was based on the reaction of iron with chelator MRB12, a greener alternative chromogenic reagent, and the reaction of manganese with zincon, within a single manifold. The developed SI method enabled the determination of iron in the range 0.10-1.00 mg L-1, and manganese in the range 0.25-2.5 mg L-1 with a limit of detection of 0.08 mg L-1 for iron and 0.24 mg L-1 for manganese. The determination of both parameters was made in 6 minutes, in triplicate. The application to monitor laboratory scale soil core columns (LSSCs), as a simulation of the soil leaching process, proved its efficiency to assess potential contamination of ground waters. Iron and manganese contents were effectively analysed in two different scenarios to mimic the leaching process with rainwater and fertilizer.
- Sequential injection method for the determination of macro and micro nutrients in soilsPublication . Nunes, Maria J. M.; Mesquita, Raquel B. R.; Ribas, Tânia C. F.; Rangel, António O. S. S.The objective was to devise a single flow analysis manifold able to monitor macro and micro nutrients in soil leachates and extracts. Several analytes were targeted, namely nitrate, nitrite (1) and phosphate (2) as essential nutrients, followed by some metal ions such as calcium, magnesium (3) , iron and manganese (4) . The sequential injection systems for the individual determinations were already reported, and now a single manifold (Figure) for a multiparametric determination is proposed.
- Single flow-based system for the automatic multiparametric nutrients (NPK & Fe) assessment in soil leachatesPublication . Ribas, Tânia C. F.; Nunes, Maria J. M.; Mesquita, Raquel B. R.; Rangel, António O. S. S.A multiparametric sequential injection system for the determination of phosphate, nitrite, nitrate, potassium, and iron(III) in a single manifold was developed. The main goal of the proposed method was to develop an efficient tool to assess a number of essential chemical compounds in soils, providing the corresponding information on soil fertility and, additionally, information on possible groundwater contamination. The method was applied for the quantification of the aforementioned parameters in simulated leachates produced in laboratory-scale core columns. The relative standard deviations of ten replicate analyses of a standard were: 6% for phosphate; 2% for nitrite; 2% for nitrate; 5% for potassium; and 6% for iron(III). The limits of detection and quantification were: 2.15 and 7.18 μmol/L for phosphate determination; 0.22 and 0.73 μmol/L for nitrite determination; 3.42 and 8.00 μmol/L for nitrate determination; 39 μmol/L (limit of detection) for potassium determination; and 0.46 and 1.85 μmol/L for iron(III) determination. The sequential injection system was successfully applied for the quantification of multiple soil chemical components (PO43−, NO2−, NO3−, K+, and Fe3+) in soil leachates. The analysis of a sample, involving all the analytes, has a duration of 28 min.