SELECTIVE DETERMINATION OF ANTIMONY(III) AND ANTIMONY(V) IN LIVER-TISSUE BY MICROWAVE-ASSISTED MINERALIZATION AND HYDRIDE GENERATION ATOMIC-ABSORPTION SPECTROMETRY

Antimony(III) and antimony(V) species have been selectively determined in liver tissues by optimizing the acidic conditions for the evolutio n of stibine using the reduction with sodium borohydride. The results show that a response for Sb(III) of 0.5 to 20 mu g l(-1) was selective ly obtained from samples in a 1 mol l(-1) acetic acid medium. The best response for total antimony from 1 to 20 mu g l(-1) is obtained after sample treatment with a 0.5 mol l(-1) sulfuric acid and 10% w/v potas sium iodide. Microwave digestion has been necessary to release quantit atively antimony species from sample slurries. The amount of Sb(V) was calculated from the difference between the value for total antimony a nd Sb(III) concentrations. A relative standard deviation from 2.9 to 3 .1% and a detection limit of 0.15 and 0.10 mu g l(-1) for Sb(III) and total Sb has been obtained. The average accuracy exceeded 95% in all c ases comparing the results obtained from recovery studies, electrother mal atomic absorption spectrometry and the analysis of certified refer ence materials.