Gold nanoparticles grafted manganese doped Fe3O4 nanoparticles for determination of short-term release of silver and lead from dental amalgam in saliva

Ethylene glycol bisthioglycolate modified gold nanoparticles grafted Mn doped Fe3O4 nanoparticles (Au@Mn-Fe3O4 NPs) adsorbent was synthesized and applied for extraction and preconcentration of trace amounts of Ag+ and Pb2+ ions in artificial and natural saliva. The adsorbent was characterized by transmission electron microscopy (TEM), Brunauer–Emmett–Teller analysis (BET), X-ray diffraction spectroscopy (XRD) and vibrating-sample magnetometer  (VSM) [h1] techniques and Fusayama artificial saliva was prepared and used as a blank sample. Natural saliva samples were collected from nine volunteers who exposed to posterior decayed teeth amalgam filling, and short-term release of heavy metal ions was assessed in 24, 72 and 96 h after filling. The main factors affecting extraction and desorption efficiency of target ions have been investigated. In Optimum conditions, the detection limits of 0.23 and 0.11 ng mL-1 with preconcentration factors of 94 and 95 were obtained for Ag+ and Pb2+ ions, respectively. The results revealed that the adsorbent has high  capacity and good reusability for extraction and preconcentration of target metal ions in relatively high saline solution like biological fluids.