A highly selective fluorescent probe for pyrophosphate detection in aqueous solutions

A novel and simple fluorescence enhancement method is introduced for selective pyrophosphate (PPi) sensing in an aqueous solution. The method is based on a 1:1 metal complex formation between tris(8-hydroxyquinoline-5-sulphonate) thulium(III) [Tm(QS)3] and PPi ion. The linear response covers a concentration range of 1.6 x 10(-7)1.0 x 10(-5) mol/L PPi and the detection limit is 2.3 x 10(-8) mol/L. The association constant of Tm(QS)3PPi complex was calculated as 2.6 x 105mol/L. Tm(QS)3 shows a selective and sensitive fluorescence enhancement toward PPi ion in comparion with I3-, NO3-, CN-, CO32-, Br-, Cl-, F-, H2PO4- and SO42-, which is attributed to higher stability of the inorganic complex between pyrophosphate ion and Tm(QS)3. Copyright (C) 2011 John Wiley & Sons, Ltd.