A turn-on hydrazide oxidative decomposition-based fluorescence probe for highly selective detection of Cu2+ in tap water as well as cell imaging

Copper (II) is one of the most important metal ions for the human body that act as a catalytic cofactor for many metalloenzymes and proteins, and its homeostasis disruption could lead to many neurological diseases. The reported probes for Cu (II) determination are mostly based on fluorescence quenching mechanism, which provides low precision and reliability. In the present work, a turn-on fluorescence probe, (Z)-1-[2-oxo-2-[2-[1oxoaceanthrylen-2 (1H)-ylidene]hydrazinyl]ethyl]-pyridinium (OAHP), for highly selective detection of Cu2+ was developed. Hydrazide moiety of OAHP quenches probe fluorescence; however, upon its reaction with Cu, oxidative cleavage of the hydrazide moiety and intramolecular cyclization occurs, forming oxadiazole derivative with strong fluorescent properties. In this context, OAHP displayed significant fluorescence enhancement with increasing levels of Cu2+. OAHP could detect Cu2+ selectively with a detection limit of 18 nM (1.1 ppb). This is the first report for a probe that uses the ability of Cu2+ to induce oxidative decomposition of hydrazide with intramolecular cyclization, and it showed exceptional selective performance and exquisite sensitivity. Next, the method was applied successfully for monitoring Cu2+ in tap water samples with good accuracy (found% of

Automated summary

Copper (II) is an important metal ion for the human body and disruption of its homeostasis can lead to neurological diseases. Most reported probes for Cu (II) determination are based on fluorescence quenching mechanism, which has low precision and reliability. In this study, a new turn-on fluorescence probe with high selectivity and sensitivity for Cu2+ detection has been developed and successfully applied for monitoring Cu2+ in tap water.