Sulfur-nanoparticle-based method for separation and preconcentration of some heavy metals in marine samples prior to flame atomic absorption spectrometry determination

The application of sulfur-nanoparticle-loaded alumina as an efficient adsorbent for the solid-phase extraction (SPE) and determination of trace amounts of Cd, Cu, Zn, and Pb ions was investigated in marine samples using flame atomic absorption spectrometry (FAAS). The nanometer-sized sulfur particles were synthesized in situ, physically loaded onto alumina microparticles, and the parameters influencing the preconcentration of the analytes, such as the pH, solution flow rate and volume, eluent solution, and interfering ions, were examined. The results showed that the optimal conditions for quantitative recovery of the metal ions by adsorption and elution on the sulfur nanoparticles (SNPs) was achieved by employing a flow rate of 15 mL min−1, a pH of 8.5 for the sample solutions, and an eluent composed of 3.0 mol L−1 HNO3 in methanol. The detection limits of this method for Cd, Zn, Cu, and Pb ions were 0.30, 0.21, 0.24, and 0.63 μg L−1 (n = 10), respectively. Application of the proposed method to the analysis of fish certified reference material (DORM-3) produced results that were in good agreement with the certified values. The proposed method was also successfully applied to the determination of analytes in marine samples, including seawater, fish, and oysters.