VALIDATION OF THE INORGANIC SELENIUM SPECIATION BY THE HG-QFAAS METHOD USING EXPERIMENTAL-DESIGNS

An optimization of the hydride generation quartz furnace atomic absorp tion spectrometry (HG-QFAAS) method used for selenium speciation was p erformed for inorganic Se determination. Experimental designs at two l evels, including five factors, were used. They allowed the evaluation of the influence of each analytical variable on peak area, repeatabili ty and signal-to-noise ratio (S/N). The absolute and relative detectio n limits obtained are respectively 0.7 ng and 0.014 ng.mL(-1) of Se(VI ) (3 sigma). The absorbance is linear over the range 0.7-45 ng. A 5.45 % relative standard deviation is obtained for six determinations of 10 ng of Se(VI) calibrant solution. The analysis of four aqueous samples - synthetic and natural - was carried out in order to validate the op timization. The Se(IV), Se(VI) and total inorganic selenium contents d etermined by the HG-QFAAS method were compared with values given by el ectrothermal atomic absorption spectrometry and differential pulse cat hodic stripping voltammetry.