Curcumin as a colorimetric and fluorescent chemosensor for selective recognition of fluoride ion

Chemically Tapered Multimode Optical Fiber Probe for Fluoride Detection Based on Fluorescence Quenching of Curcumin

“…5(b). This particular result is ascribed to the energy transfer from Curcumin to the complex formed with fluoride ion [16]. The hydrogen bonding nature of the complex in acetonitrile was also verified by Wu et al [16] using absorption titration with ethanol and also by our group with absorption titration with ethanol and ethylene glycol.…”

“…This particular result is ascribed to the energy transfer from Curcumin to the complex formed with fluoride ion [16]. The hydrogen bonding nature of the complex in acetonitrile was also verified by Wu et al [16] using absorption titration with ethanol and also by our group with absorption titration with ethanol and ethylene glycol. We found that there was indeed a retrace of absorption curves as reported by the aforementioned group in the presence of protic solvents, especially a faster recovery in the case of the strongest protic solvent ethylene glycol as illustrated by the Fig.…”

“…8. In this case also there is a recovery of absorption spectrum of Curcumin [16] with increased addition of protic solvent ethanol (EtOH). This leads to the conclusion that hydrogen bonding does indeed play the major role in complex formation in anisole also.…”

“…Clearly formed isobestic points at 355 nm and 458 nm were also visible in the spectrum. These changes in the absorption behavior can be attributed to the effect of Fforming a complex with OH hydrogen of Curcumin [16]. This complex exists in equilibrium state with the deprotonated form of Curcumin, which is in turn formed in the presence of excess fluoride ion concentration.…”

“…This is owing to the very large hydration energy of fluoride ion, which makes the operation of sensors in aqueous media difficult [15]. An interesting method to detect fluoride ion was reported by Wu et al using Curcumin as the sensing agent [16]. Curcumin responded to fluoride ion via the formation of a hydrogen bonded complex, which led to significant changes in its optical properties.…”