TD-DFT method of analysis of fluorescent detection of bisulphite ion in an aqueous solution by a pyrene-based chemodosimeter

A new pyrene-based chemodosimeter (RS3) has been designed and synthesized, which is found to be a promising fluorescent probe for detection of bisulphite ion in DMSO:Na2HPO4/citric acid buffer of pH 5. H-1 NMR titration indicates that nucleophilic addition of HSO3 to vinylic C-atom of RS3 terminates the pi-conjugation and consequently enhanced the fluorescence significantly. The sensing mechanism is further confirmed by density functional theory (DFT) and time dependent density functional theory (TD-DFT) methods. The binding constant of the 1:1 RS3-HSO3 adduct is found to be 0.7 x 10(3) M-1. The probe RS3 exhibits high selectivity towards bisulphite ion with a limit of detection of 0.15 mu M, which is lower than the maximum permissible limit of bisulfite ion (1.25 mu M) in food products required by the European Union Regulations. Further, the probe RS3 has been used for the determination of HSO3 in real samples such as distilled water, tap water, red wine, jaggery and white sugar and also successfully applied for the bio-imaging of HSO3 in live cells. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

A new pyrene-based chemodosimeter (RS3) for the detection of bisulphite ion in DMSO:Na2HPO4/citric acid buffer has been designed and synthesized, showing promising fluorescent properties and high selectivity.