We have mentioned in Section

Fig. 2 shows the emission spectra of Fe3O4@MCM-41@R6 turbid solution (5 mg in 10 mL phosphate buffered saline, ╬╗ex = 520 nm) under various Hg(II) concentrations. It is observed that the emission intensity at 571 nm is rather weak in the absence of Hg(II) ions, suggesting that most of the grafted probe TIC10 take the non-emissive spirolactam structure. In the presence of Hg(II) ions, the emission intensity at 571 nm becomes stronger, showing an obvious emission “off-on” effect towards Hg(II) ions.