A dual-channel chemosensor could successively detect CN^- and HSO₄^- in an aqueous solution and act as a keypad lock

A dual-channel sensor (T) based on a phenazine derivative has been designed and synthesized. The sensor T could successively detect CN^- and HSO₄^- in aqueous solution with high selectivity and sensitivity. Upon the addition of water solution of CN^-, the sensor T showed an immediate visible color changes from yellow to orange, meanwhile, the yellow fluorescence of sensor T quenched. More interestingly, the color and fluorescence could be recovered upon the addition of HSO₄^- into the CN^- contained sensor T solutions. Other anions couldn't induce similar response. The detection limits of T to CN^- and T + CN^- to HSO₄^- were estimated to be 8.90 × 10^-8 M and 1.46 × 10^-10 M, respectively. Notably, this successive response feature of sensor T makes it has a potential utility for CN^- and HSO₄^- detection in aqueous solution.