naked magnetite nanoparticles for both clean-up and solid-phase extraction-trace determination of mercury

A new solid-phase extraction method was developed for trace determination of hg(ii) by using a small amount of naked magnetite nanoparticles as an adsorbent. the magnetite nanoparticles were characterized by x-ray diffraction, scanning electron microscopy and transmission electron microscopy. the adsorbed hg(ii)-dithizone complex was eluted with 1.0 ml aliquot of an acidic 1-propanol solution prior to electrothermal atomic absorption spectrometry. a huge positive effect was found on the mercury adsorption by ionic strength. under optimized condition, a linear calibration curve was obtained for mercury in the range of 0.2–50 ng ml−1 with relative standard deviation in the range of 0.5–2.0%. the limit of detection and enrichment factor were 0.01 ng ml−1 and 98.3, respectively. the effects of coexisting ions were studied extensively, and a new clean-up procedure was used to remove the matrix effects by using a simple sample pretreatment step using a little amount of magnetite nanoparticles. the method was successfully applied to the determination of hg(ii) in different water and human urine samples and a commercial sodium nitrate.