Separation/preconcentration and speciation of very low amounts of selenium using modified magnetite nanoparticles before electrothermal atomic absorption spectrometric determination in water

A new, simple, fast and reliable procedure for the speciation of selenium(iv)and selenium(vi) using solid-phase extraction (spe) with ammonium pyrrolidine dithiocarbamate/sodium dodecyl sulfate immobilized on alumina-coated magnetite nanoparticles(apdc/sds-acmnps), followed by electrothermal atomic absorption measurement, isproposed. the method is based on the adsorption of se(iv) on modied acmnps. totalselenium concentration in dierent samples was determined as se(iv), after reduction ofse(iv) to se(vi), by heating the samples in a microwave oven with 4.0 mol l??1 hcl. se(vi)concentration was calculated as the dierence between the total selenium content andse(iv) content. the eect of parameters such as ph, amount of adsorbent, contact time,sample volume, eluent type, and hcl and apdc/sds concentration ratios as modiers,on the quantitative recovery of se(iv), was investigated. under optimal experimentalconditions, the preconcentration factor, detection limit, linear range and relative standarddeviation (rsd) of se(iv) were 125 (for 250 ml of sample solution), 0.05 ng ml??1, 0.1-8.0 ng ml??1 and 4.1% (for 5.0 ng ml??1; n = 7), respectively. this method avoided thetime-consuming column-passing process of loading large volume samples in traditional spethrough the rapid isolation of apdc/sds-acmnps with an adscititious magnet. theproposed method was successfully applied to the determination and speciation of seleniumin dierent water samples and suitable recoveries were obtained.