抄録
In the present work a reliable and highly sensitivity method for selenium speciation, based on sorbent pre-concentration using a mini column of anionic exchanger (LC-SAX) coupled in line to Graphite Furnace Atomic Absorption Spectrometry (GFAAS) is described. Chemometric approaches for those factors that exert influence on pre-concentration has been employed using a full 23 factorial design. Under acid medium (pH 2) only Se(VI) was determined while in the pH range of 6 up to 8, both Se(IV) and Se(VI) can be determined. Unlike from some previously published methods for selenium speciation, in which Se(VI) is determined by subtracting Se (IV) from total selenium, in the present work a system with three equations was proposed and this system was based on the principle of additivity of absorbances. The limit of detection and quantification for Se(IV) were 3.1 x 10-2 μg L-1 and 1.0 x 10-1 μg L-1 , respectively and for Se(VI) were 4.9 x 10-2 μg L-1 and 1.6 x 10-1 μg L-1, respectively.
