A Highly Sensitive and Selective Colorimetric Hg²⁺ Ion Probe Using Gold Nanoparticles Functionalized with Polyethyleneimine

Figure 1

(a) UV-Vis absorption spectra of (1) AuNPs (black line), (2) PEI-AuNPs (red line), and (3) PEI-AuNPs conjugated with Hg²⁺ (green line). (b) TEM image of PEI-AuNPs (left) and the corresponding particle-size distribution histogram (right). (c) TEM image of PEI-AuNPs conjugated with Hg²⁺ (left) and particle-size distribution histogram (right).

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