Highly Selective and Sensitive Luminescent Turn-On Probe for Pyrophosphate Detection in Aqueous Solution

In this work, a luminescent probe (RuE, the abbreviation of Ru(bpy)(2)(E)Cl-2, where bpy=2,2'-bipyridine, E=N,N'-5,6-(1,10-phenanthroline)-bis(2-hydroxy benzaldehyde)diamine) based on the ruthenium(II) bipyridyl complex conjugated with functionalized Schiff bases, which revealed a highly selective luminescence quenching by Cu2+ in aqueous solution was prepared. Because of the quenching effect of copper ions, the luminescence of RuE-Cu(II) solution was weak. However, in the presence of pyrophosphate (P 2O4- 7, PPi), the strong binding ability of PPi to Cu2+ can promote the break up of RuE-Cu(II) complex and then recover the luminescence. Most of other potential interfering anions, including strong interfering substance, like phosphate, ATP, ADP and AMP can not enhance the luminescence apparently. Therefore, the RuE-Cu(II) ensemble can act as an excellently selective and sensitive turn-on probe for the sequential determination of PPi in aqueous solution. The detection limit of the probe for PPi was 0.58 nM and the linear concentration range was 0-16 mu M. In addition, the potential applicability of this probe has been demonstrated by the successful detection of PPi in human urine samples.