A new strategy for the ratiometric fluorescence detection of Zn(II) in the surfactant solution

A new strategy derived from the intramolecular charge transfer mechanism was employed to create a ratiometric sensing system for Zn2+ in aqueous solution by using sodium dodecyl sulfate (SDS) micelles as the scaffold. The amphiphilic carboxamidoquinoline-based sensor (AQZ2Cl) was simultaneously solubilized at different locations in the SDS micelle. Some AQZ2Cl molecules were adsorbed at the micelle–water interface and emitted a fluorescence-enhancing and red-shifted signal upon binding Zn2+. And the others were incorporated into the palisade layer of the micelle, in which the produced bands had no appreciable changes with the addition of Zn2+, thus acting as an internal standard and allowing AQZ2Cl as a ratiometric sensor for the detection of Zn2+.

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► A strategy for the ratiometric Zn2+ detection was described in the micellar solution.
► Two emission bands of the Zn2+-free and bound sensor can coexist in the SDS solution.
► The band of the Zn2+-free sensor acted as an internal standard during the titration.