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  • Determination of mercury in...
    da Silva, Maria José; Paim, Ana Paula S.; Pimentel, Maria Fernanda; Cervera, M. Luisa; de la Guardia, Miguel

    Analytica chimica acta, 05/2010, Volume: 667, Issue: 1
    Journal Article

    A cold vapor atomic fluorescence spectrometry method (CV-AFS) has been developed for the determination of Hg in rice samples at a few ng g −1 concentration level. The method is based on the previous digestion of samples in a microwave oven with HNO 3 and H 2O 2 followed by dilution with water containing KBr/KBrO 3 and hydroxylamine and reduction with SnCl 2 in HCl using external calibration. The matrix interferences and the effect of nitrogen oxide vapors have been evaluated and the method validated using a certified reference material. The limit of detection of the method was 0.9 ng g −1 with a recovery percentage of 95 ± 4% at an added concentration of 5 ng g −1. The concentration level of Hg found in 24 natural rice samples from different origin ranged between 1.3 and 7.8 ng g −1.