Fig. 5
UV/Vis absorption spectra of bare tested solutions: a Sample A b Sample B c Sample C and d Sample D, respectively. The inset figure of Fig. 5a presented the photographs of tested solutions for further detection. UV/Vis absorption spectra of e Sample A f Sample B g Sample C and h Sample D in the presence of LS-AuNP probes, respectively, where the obvious colorimetric detection for selectively sensing Cu2+ ions could be evidenced