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 (Y3+)-norfloxacin (NFLX) complex as a fluorescence (FL) probe. NFLX can form a stable binary complex with Y3+ and markedly enhances the weak FL signal of the NFLX. The FL intensity of the Y3+-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 mu g 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 mu g mL(-1) BR. The presented method offers higher sensitivity with simple instrumentation and was applied successfully in detecting BR at low concentrations. (C) 2012 Elsevier B.V. All rights reserved.