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Browsing by Issue Date, starting with "2004-06"

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  • Acção social nas comunidades cristãs
    Publication . Dias, Antonino
    A acção social nas comunidades cristãs transforma a fé em caridade e promove a evangelização. Os Centros Sociais institucionalizam esta dinâmica.
    2004-06Journal article Open access Show more
  • Determination of aluminum (III) in crystallized fruit samples using a multicommutated flow system
    Publication . Tóth, Ildikó V.; Rangel, António O. S. S.; Santos, João L. M.; Lima, José L. F. C.
    A multicommutated flow system was developed for the determination of aluminum in crystallized fruit samples. Spectrophotometric determination is based on the reaction of aluminum with chrome azurol S. The binary sampling technique was implemented to improve mixing conditions and to minimize reagent consumption. Three different working zones were established (0.5-5.0, 5.0-25.0, and 10.0-100 ppm) using the zone sampling approach, allowing us to adapt the extent of the in-line dilution. The influence of the chemical and physical parameters on the performance of the system was studied. Detection limits of 0.1, 0.6, and 0.8 ppm were obtained for the lowest, the medium, and the highest dispersion system, respectively. The procedure was applied to the determination of aluminum in crystallized fruit extracts. The results were in agreement with those obtained by the reference flame atomic absorption procedure at a 95% confidence level. Repeatability (RSD) was better than 2.4% in all of the three application zones.
    2004-06Journal article Restricted access Show more