Ratiometric detection of adenosine triphosphate (ATP) in water and real-time monitoring of apyrase activity with a tripodal zinc complex ButlerStephen 2015 Two tripodal fluorescent probes Zn⋅L1,2 have been synthesised, and their anion-binding capabilities were examined by using fluorescence spectroscopy. Probe Zn⋅L1 allows the selective and ratiometric detection of adenosine triphosphate (ATP) at physiological pH, even in the presence of several competing anions, such as ADP, phosphate and bicarbonate. The probe was applied to the real-time monitoring of the apyrase-catalysed hydrolysis of ATP, in a medium that mimics an extracellular fluid.