A simple fluorophore/surfactant ensemble as single discriminative sensor platform: Identifying multiple metal ions in aqueous solution

• SDS assemblies can modulate fluorescence emission of mono-pyrene derivative.
• SDS assemblies realizes monomer-excimer co-emission of mono-pyrene fluorophore in aqueous solution.
• Fluorophore/SDS ensemble exhibits cross-reactive responses to metal ions.
• Single supramolecular sensor system can discriminate 6 quenching metal ions at same or different concentration.

A simple imidazolium-modified mono-pyrene derivative (Py-IM) is synthesized. SDS assemblies modulate its fluorescence emission from monomer emission in neat aqueous solution to monomer-excimer co-emission in pre-micelles and to monomer emission again in micellar solutions. The ensemble based on Py-IM and SDS assemblies exhibiting both monomer and excimer emission displays multiple-wavelength cross-reactive responses to cationic metal ions. This single sensor system could well discriminate 6 quenching metal ions (Fe3+, Cu2+, Pb2+, Ni2+, Co2+, and Mn2+) through principal component analysis method. Control experiments with Py-IM in the absence of SDS assemblies and in SDS micellar solutions reveal that the modulation effect of surfactant assemblies plays an important role in the cross-reactive responses of the cationic probe, which provides a general way of fabricating discriminative single sensor systems.

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