Spectrofluorimetric quantification of bilirubin using yttrium-norfloxacin complex as a fluorescence probe in serum samples

► Weak FL signal of NFLX was enhanced at 419 nm by forming binary complex with Y3+. ► The FL intensity of Y3+-NFLX complex was quenched markedly in the presence of ATP. ► NFLX can transfer energy to Y3+ and BR and form the Y3+-NFLX-ATP ternary complex. ► The reduced FL intensity of the system was correlated with the concentration of BR. ► The method is applied to determine BR at low concentration (2.8 ng mL−1) in serum.