Digestion programmes for different types of samples (milk, sausage and lyophilized pig kidney certified reference material) have been developed using a focused microwave digestor prior to the determination of selenium. The digestion step does not alter the oxidation state of the analyte; thus, the speciation of the target analyte is also achieved with the help of the microwave digestor, which facilitates a subsequent on-line reduction step in a flow injection (FI) manifold before determination by FI cathodic stripping voltammetry. Excellent recoveries for the spiked and certified values were obtained using digestion programmes which varied from 20-45 min. The on-line microwave procedure for the reduction of Se-VI affords good sensitivity and linearity (3-120 mu g l(-1), r = 0.994) of the over-all determination method, and dramatically reduces the time necessary for Se-VI reduction.
