The preparation of novel triphenylamine-based AIE-effect fluorescent probe for selectively detecting mercury(ii) ion in aqueous solution

Abstract

A TPA-ME fluorescent probe, based on triphenylamine derivative TPA-CHO, has been designed, synthesized and characterized by different spectroscopic methods successfully. TPA-ME and TPA-CHO present similar aggregation-induced emission (AIE) effects under same conditions. Due to the deprotection reaction of mercaptal promoted by mercury ions (Hg²⁺), TPA-ME exhibits excellent selectivity and anti-inference properties over other tested ions in the DMF/H₂O (f_w 70%, pH 6.8) medium. Upon increasing Hg²⁺, the fluorescence of the TPA-ME probe shows an obvious red-shift from blue to green. The fluorescence intensity has a good linearity toward Hg²⁺, with the limit of detection (LOD) below 1.23 × 10⁻⁷ mol L⁻¹. A theoretical calculation was carried out to understand the difference between TPA-ME and TPA-CHO, and experimental results have been met with simulation calculations. Along with the result of the fluorescence change, Hg²⁺ can be easily tested through a conveniently prepared test paper.