A bifunctional sensor based on Au-Fe3O4 nanoparticles (NPs) modified by ethyl 1-(2-(3
,4
-
dihydroxyphenyl)-2-oxoethyl)-1H-1,2,3-triazole-4-carboxylate (ETC) was developed. Due to the
coordination interaction between cadmium (Cd2+) and ETC, Cd2+ induced the aggregation of Au-Fe3O4
NPs from dispersion, concomitant with a change in UV–vis spectra and transverse relaxation time (T2).
The combined signals provided high selectively for Cd2+ ions.