Sensitive determination of adenosine disodium triphosphate in soil, milk, and pharmaceutical formulation by enoxacin-europium (III) fluorescence complex in solution

► Weak luminescence of Eu3+ was enhanced at 614 nm after formation of complex with ENX. ► Energy transfer occurs through FRET from ENX to Eu3+ upon excitation. ► Luminescence signal was further enhanced when ATP conjugates with ENX-Eu3+ complex. ► Luminescence intensity of Eu3+ at 614 nm was correlated with concentration of ATP. ► The method was applied to determine ATP in soil, milk, and pharmaceutical samples.