Application de la SAA électrothermique a Panalyse des matrices complexes: cas de l'arsenic dans les végétaux

This work shows the possibilities and the analytical limitations of ETA-SAA for arsenic determination in plants. Wet oxidation of these media is quantitative, but the direct determination of arsenic is strongly interferred with the presence of sulphuric acid and, principally, phosphorus, which is contained in plant matrix. In this case, only arsenic concentrations around 100 ng ml^?1 in solution (5 μg g^?1 in dry matter) can be directly determined.Because lower concentrations must be determined in unpolluted samples, two extraction procedures have been developed, both based on a preliminary reduction of As⁵⁺ to As³⁺ and a further extraction in toluene. NH₄I turns out as a better reducing agent than KI.In routine analysis, arsenic concentrations in the vicinity of 20ng g^?1 in dry matter can be easily determined under the adopted conditions.