Ultrasensitive detection of aqueous Cu ions by a coumarin-salicylidene based AIEgen

• Published in: Materials chemistry frontiers 2019-11, Vol.3 (11), p.2437-2447
• Main Authors: Padhan, Subrata Kumar, Murmu, Narayan, Mahapatra, Subrat, Dalai, M. K, Sahu, Satya Narayan
• Format: Article
• Language: English
• ISSN: 2052-1537
• DOI: 10.1039/c9qm00394k

This work reports the aggregation induced emission (AIE) behaviour of a coumarin-salicylidene Schiff base probe 3 which shows bright yellow AIE fluorescence in DMSOwater medium ( f w 80%) buffered by 10 mM HEPES at pH 7.4. The aggregated probe ( AIEgen-3 ) selectively discriminates Cu 2+ ions over a series of other interfering metal ions via a fluorescence onoff strategy through a CHEQ process. DLS measurements revealed an average particle size of 372 nm for AIEgen-3 at an 80% water fraction, which dramatically increases to 656 nm in the presence of Cu 2+ ions, indicating the formation of more structured aggregates, which was further supported by TEM and ESI-MS experiments. A comprehensive analysis of the binding characteristics and interference studies of AIEgen-3 with various metal ions have been carried out by fluorescence and UV-visible experiments. AIEgen-3 shows a fluorescence detection limit (LOD) of 24 nM (1.5 ppb) for Cu 2+ ions, which is considerably far below the values of detection limits recently reported for other Cu 2+ ion sensors in aqueous medium. Further, the analytical applications of AIEgen-3 have been demonstrated by the estimation of Cu 2+ ions in tap water and pharmaceutical samples both in solution and the solid phase, which shows the potentiality of the probe for on-site detection of Cu 2+ ions in chemical, environmental and biological samples. This work reports the aggregation induced emission (AIE) behaviour of a coumarin-salicylidene Schiff base probe 3 which demonstrates ultrasensitive detection of aqueous Cu 2+ ions in nanomolar range via a fluorescence onoff strategy.