A Reversible Bis(Salamo)-Based Fluorescence Sensor for Selective Detection of Cd(2+) in Water-Containing Systems and Food Samples

A novel, simple, highly selective, and sensitive fluorescence chemosensor for detecting Cd(2+) that was constructed from a bis(salamo)-type compound (H(4)L) with two N(2)O(2) chelating moieties as ionophore was successfully developed. Sensor H(4)L could show fluorescence turn-on response rapidly and significant selectivity to Cd(2+) over many other metallic ions (Cu(2+), Ba(2+), Ca(2+), K(+), Cr(3+), Mn(2+), Sr(2+), Co(2+), Na(+), Li(+), Ni(2+), Ag(+), and Zn(2+)), and a clear change in color from colorless to yellow that can be very easily observed via the naked eyes in the existence of Cd(2+), while other metallic ions do not induce such a change. Interestingly, its fluorescent intensity was increased sharply with the increased concentration of Cd(2+). The detection limit of sensor H(4)L towards Cd(2+) was down to 8.61 × 10(−7) M.