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

A simple and sensitive spectrofluorimetric method was developed to determine trace amounts of bilirubin (BR) using yttrium (Y ³)- norfloxacin (NFLX) complex as a fluorescence (FL) probe. NFLX can form a stable binary complex with Y ³ and markedly enhances the weak FL signal of the NFLX. The FL intensity of the Y ³-NFLX complex decreased significantly in the presence of BR in a buffer solution at pH=7.2. Under optimal conditions, the FL intensity decreased according to the BR concentration and showed a good linear relationship in the range of 0.03-2.3 μg mL ^-1 of BR with a correlation coefficient of 0.9988. The limit of detection for the determination of BR was 2.8 ng mL ^-1 with a relative standard deviation (RSD) of 1.55% for five replicate determination of 0.05 μg mL ^-1 BR. The presented method offers higher sensitivity with simple instrumentation and was applied successfully in detecting BR at low concentrations.