Triazole functionalized gold nanoparticles for colorimetric Cr3+ sensing

Triazole functionalized gold nanoparticles (NTP@AuNPs) were synthesized through a click reaction and have been developed for sensitive and selective colorimetric Cr3+ detection. Gold nanoparticles were prepared by reducing HAuCl4 with sodium citrate and then using 4-(prop-2-ynyloxy)pyridine (PP) as the capping agent. The acetylene part of PP and the azide part of 1-(azidomethyl)-4-nitrobenzene were combined to form a triazole structure through a click reaction. Aggregation of NTP@AuNPs was induced immediately in the presence of Cr3+ ions, yielding a color change from red to purple. This Cr3+-induced aggregation of NTP@AuNPs was first monitored using the naked eye and then UV–vis spectroscopy with a detection limit of 1.4 μM. In addition, NTP@AuNPs were also used to detect Cr3+ in lake water samples, with low interference.