Figure 2

(a) Photographic images of colorimetric detection of various metals in water through simple naked-eye analysis. (b) Absorbance changes of the novel rhodamine-based probe in the presence of various metal ions and for example UV–visible spectra in the presence of Ni2+ and Fe3+ (inserted). (c) The UV–visible absorption spectra of the probe in the absence (blue) and presence (red) of Ni2+.