Reaction-based fluorescent detection of diamines via tuning the probe aggregation

A key factor in enhancing molecular-level detection is the analyte's potential to direct a visible photophysical characteristic. Here, we describe a molecular probe, Xanth-CHO, and studies on how ethylenediamine (EDA) and 1,3-diaminopropane (DAP) cause fluorescence turn-on reactions that allow their detection in an aqueous buffer. Since Xanth-CHO is in an aggregate state in the aqueous buffer, the presence of EDA or DAP modifies this state and causes the probe to undergo radiative decay by producing imine products of Xanth-CHO. The fluorescence intensity rises linearly with increasing EDA or DAP concentrations, permitting detection limit at the nanomolar level. The efficiency of Xanth-CHO in detecting EDA or DAP has been demonstrated by the competitive analysis and evaluation of real water samples. Further, probe-coated TLC strips, as a low-cost detection tool, were deployed for the vapor phase recognition of EDA and DAP vapors during fish spoilage.