Dual role of silatranized Schiff base as a fluorimetric probe and a linker to functionalize graphene oxide for the selective detection and adsorption of zinc ions

Abstract

Herein, a Schiff base probe possessing flexible ONNO architecture has been designed and explored for the analysis of metallic species. Simple protocols are illustrated for the syntheses of Schiff base probe (P), a silatranyl incorporated Schiff base probe (P-Silt) and graphene oxide functionalized with Schiff base probe (P@SiO2@GO) for the recognition and adsorption of zinc ions. The Schiff base probe P was derived from the condensation reaction of N-(2-hydroxyethyl)ethylenediamine and 2-hydroxy-4-methoxybenzophenone. It was then derivatized to its silatranyl counterpart (P-Silt) to incorporate a hydrolyzable cage for linking probe P on the surface of graphene oxide. The silatranyl derivative P-Silt displayed a selective spectrofluorimetric signal for zinc ions due to chelation-enhanced fluorescence effect (at 453 nm) which enabled the detection of zinc ions upto 7.09 nM (LOD). In addition, P linked graphene oxide P@SiO2@GO was utilized for the selective removal of zinc ions and proved as a highly efficient adsorbent (Qm = 88.34 mg g−1) even in the presence of co-existing ions. It can be re-used as a sorbent for SPE cartridges up to four cycles with 100% efficiency.