Biochemistry & Analytical Biochemistry

Abstract

A Photo-Induced Electron Transfer Based Chemosensor for the Selective Detection of Zn2+ Ions

Narendra Reddy Chereddy, Sathiah Thennarasu and Asit Baran Mandal

Aim: The chemosensors permitting naked eye detection of toxic metal ions are user-friendly, portable and obviate the requirement of sophisticated equipments. The objective of the present study was to develop a PET (photoinduced electron transfer) based chemosensor for Zn2+ that changes its color upon binding to Zn2+ allowing naked eye detection.

Methods: A new 4-piperazino-1,8-naphthalimide based fluorescent probe 1 was synthesized and its structure was determined using NMR and XRD techniques. The solvatochromic effects on the absorbance and fluorescence characteristics of 1 in aqueous and non-aqueous media were explored. Metal ion competition experiements were performed to monitor the interference of common ions like Li+, Na+, K+, Cu2+, Mg2+, Ca2+, Cr3+, Mn2+, Fe2+, Co2+, Ni2+, Zn2+, Cd2+, Hg2+ and Pb2+.

Results and conclusion: The significance of the solvatochromic effect in colorimetric and fluorometric detection of Zn2+, and turn-off sensing of Cu2+ via metal ion displacement have been emphasized. In non-aqueous environment, probe 1 acts as a turn-on chemosensor for Zn2+ and as a turn-off chemosensor towards Cu2+ and thereby, enables the detection of Zn2+ and Cu2+ ions in two different modes. In aqueous environment, the probe 1 acts only as a turn-off chemosensor for Cu2+ ion