Quinoline group based fluorescent sensor for detecting zinc ions in aqueous media and its logic gate behaviour

A highly sensitive method for quantitative determination of Zn2+ in water has been developed by using a novel fluorescent sensor NQA: (N-Quinolin-8-yl-2-[(quinolin-8-ylcarbamoylmethyl)-amino]-acetamide). The sensor displays great selectivity for Zn2+ in the presence of other metal ions in aqueous solution and possesses an excellent sensitivity of about 2×10−8 M for Zn2+. The binding stoichiometry, binding affinity, and pH sensitivity of the sensor have also been studied. Furthermore, the fluorescent changes of NQA upon the addition of cations (Cu2+ and Zn2+) are utilized to construct an INHIBIT logic gate at the molecular level, using Cu2+ and Zn2+ as chemical inputs and the fluorescence intensity as output. NQA has ideal chemical and spectroscopic properties that satisfy the criteria for further biological and environmental applications.