A highly selective ratiometric fluorescent chemosensor for Cd2+ ions.

A phenanthroxazole-based fluorescent sensor for Cd(2+) has been developed. Of particular significance is the specific ratiometric response of the sensor toward Cd(2+) without interference from other biologically important metal ions including Zn(2+). The test paper made of this sensor exhibits both absorption and fluorescent color changes when exposed to Cd(2+) aqueous solution.