Figure 3.

Elemental distribution analysis of EDTA•2Na@SiO₂‐Au chelates and investigation of the efficacy of EDTA•2Na on sequestering Au³⁺ ions by ICP‐MS technique. a) TEM image of EDTA•2Na@SiO₂‐Au chelates. b–d) EDX mapping image of EDTA•2Na@SiO₂‐Au chelates (blue = Si, yellow = Au). 500 µL of HAuCl₄ (2 × 10⁻³ m) were added to EDTA•2Na@SiO₂ solutions for chelation and detected through X‐ray (EDX) mapping. e,f) 500 µL of HAuCl₄ (0.00638 g L⁻¹) were added to EDTA•2Na@SiO₂ solutions for chelation and after centrifugation the changes in Au contents were detected through ICP‐MS. g) The precipitates of EDTA•2Na@SiO₂‐Au chelates obtained from (b) were redispersed in water and further incubated with 500 µL of trisodium citrate solution (2 × 10⁻³ m). The contents of Au in supernatant after centrifugation were detected through ICP‐MS. h) UV–vis spectra of HAuCl₄, EDTA•2Na, and their mixture.