Fluorometric sensor based on bisterpyridine metallopolymer: detection of cyanide and phosphates in water

A poly(ethylene glycol) (PEG) decorated bis(terpyridine) zinc coordination polymer acts as an anion-responsive material in 100% aqueous solution. Depending on the binding and association constants to Zn(II), the addition of different anions leads to increased emission intensity and/or a shift of the emission wavelength. The sensor was addressed with a collection of common salts to survey the selectivity of the emission response. Phosphate and cyanide, representing the strongest anion binding to zinc(II), were detected even in the presence of other ions in tap water. Biologically relevant phosphates such as diphosphates and adenosine-5'-triphosphate (ATP) also produced a strong response. Because the binding constants with Zn(II) are very high, anion concentrations in the range of 10(-6) to 10(-7) M are sufficient.