Detection of cyanide and sulfide ions by different mechanisms using a fluorescent chemical sensor containing a fluorophore and a potential ligand for metal complexes

Abstract

Here, we present a fluorescent chemical sensor for the simultaneous detection of CN- and S2- ions, which are highly toxic to humans and the environment. When the BPMA-Flu-Cu2+ complex comprising BPMA-Flu, a fluorophore combined with Cu2+, was used, the fluorescence was turned off. However, the fluorescence was turned on again by the addition of CN- and S2- ions. BPMA-Flu is a unique compound containing both a fluorophore and a ligand coordinated to a metal ion. This strategy using the proposed BPMA-Flu-Cu2+-based fluorescent chemical sensor facilitated quantitative analysis of CN- and S2- ions with high selectivity and sensitivity, despite varying detection mechanisms. The detection limit was as low as 290 nM and 74 nM for CN- and S2- ions, respectively. The sensor was selective and excluded other anions at concentrations 10-fold higher than those of CN- and S2- ions. The recovery rates did not exceed 10% of the original values for the detection of CN- ions in rainwater and tap water. These results indicate acceptable accuracy and precision for practical applications. A fluorescent chemical sensor for the detection of CN- and S2- was demonstrated based on BPMA-Flu-Cu2+ complex. Addition of Cu2+ to BPMA-Flu quenches fluorescence, but addition of CN- and S2- restores fluorescence.