Detection of organic amines using a ratiometric chromophoric fluorescent probe with a significant emission shift

Abstract

Taking advantages of both the well-known α,β-unsaturated structure and the special nucleophilicity of organic amines toward its acceptor moieties, intramolecular charge transfer as a signaling mechanism is used to design and synthesize a new ratiometric chromophoric fluorescent probe (BI-CA-ID) with large emission shifts toward organic amines. This probe is employed for the detection of organic amines with high selectivity and sensitivity and a “naked-eye” color change (from red to colorless). Ultraviolet–visible and fluorescence spectrometric measurements are used to determine detection limits as low as 0.024 and 0.43 μM. Furthermore, nucleophilic addition of the amine on the α,β-unsaturated of BI-CA-ID indicated that the sensing mechanism occurs via interruption of the π-conjugation.

Enlightening the Path to Protein Engineering: Chemoselective Turn-On Probes for High-Throughput Screening of Enzymatic Activity

“…Another reagent relying on the nucleophilic attack of the amine onto an electrophilic center was developed by Wu et al 669 Their synthetically readily accessible iminium dye BI-CA-ID 39 effectively recognized primary amines upon reaction by ratiometric discoloration of the dye solution and emergence of a blue-shifted fluorescence emission with a peak at 382 nm. The reaction with primary and secondary amines was reported to be instantaneous.…”