LAUSR

Abstract A reversible dual-channel chemosensor (W) based on double Schiff-base for ultrasensitive fluorescence detection of Cu2+ in DMSO solution has been designed and synthesized. Upon the addition of Cu2+, the chemosensor W showed visible color changes (from yellow to colorless) and the fluorescence was immediately quenched. The fluorescence spectrum detection limit for Cu2+ was 4.87 nM, which is much better than most reported fluorescent sensors for Cu2+. Interestingly, the sensing behavior was found to be reversible with addition of EDTA, which indicated that W not only could act as a nice candidate for Cu2+ and EDTA controlled “ON-OFF-ON” fluorescence switch, but was utilized as an ultrasensitive IMPLICATION logic gate at the molecular level. More importantly, ion test strips based on W were fabricated, which could act as convenient and efficient test kits to detect Cu2+ for “in-the-field” measurement.