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  • Development of a Turbidimetric Sequential Injection System to Monitor the Codfish Desalting Process
    Publication . Santos, Inês C.; Mesquita, Raquel B. R.; Galvis-Sánchez, Andrea C.; Delgadillo, Ivonne; Rangel, António Osmaro S. S.
    Salt-cured codfish represents an ancient process of preservation but requires the rehydration of the codfish with the correspondent salt removal. This work describes the development of a sequential injection system for the online turbidimetric determination of chloride during a simulated desalting process. The samples are directly aspirated to the manifold with no need for previous offline treatments; this was possible due to the use on an inline dialysis process; a quantification range from 50.0 mg/L to 20.0 g/L was established using the same manifold configuration. For monitoring the entire process, involving several chloride determinations (ca. 10), less than 3 mL of the desalting water was needed. Furthermore, the overall reagent consumption was quite low: 0.211 mg of AgNO3, 30.6 mg of HNO3, and 31.1 μg of PVA per determination. The accuracy of the system was evaluated by comparison with a potentiometric reference method. The determination rate was 28 and 31 h−1 according to the chloride concentration range. Several simulated desalting processes, under different conditions, were effectively monitored with the developed method.
  • Membrane-based separation in flow analysis for environmental and food applications
    Publication . Santos, Inês C.; Mesquita, Raquel B. R.; Rangel, António O. S. S.
    Membrane-based separation techniques have been used as an efficient process for analyte separation or enrichment and matrix removal. By coupling these techniques to flow-based analysis, sample preparation and analyte detection can be automated and miniaturized. Different membrane separation techniques are available but the most used in flow analysis are gas diffusion, dialysis, supported liquid membranes and polymer inclusion membranes. The current state of the art of membrane-based separations hyphenated with flow techniques is presented along with a discussion of the applications to environmental and food analysis. Moreover, a brief description of gas diffusion, dialysis and membrane extraction techniques is also included.