Sensitized chemiluminescence determination of fluorouracil in pharmaceutical and biological fluids based on potassium permanganate oxidation in the presence of formaldehyde

A novel chemiluminescence (CL) reaction system was established for the anticancer drug fluorouracil (5‐FU). We developed a formaldehyde‐sensitized CL emission mechanism for 5‐FU‐KMnO 4 ‐HCl systems by comparing the fluorescence emission with CL spectra. The illuminant was the singlet‐state bimolecular oxygen 1 O 2 1 O 2 ( 1 Δ g 1 Δ g ), which is from 1 O 2 ( 1 Δ g ) produced in the reaction system, and emits CL spectra at 639 nm. The presence of formaldehyde can sensitize CL emission by accelerating the generation of 1 O 2 ( 1 Δ g ). The optimum conditions for CL emission were investigated. The relationship between the relative CL intensity and the concentration of the analyte showed good linearity. The determination limit was 3 × 10 −8  g mL −1 . The relative standard deviation (SD) was 1.8%. The proposed method was applied to the determination of fluorouracil in pharmaceutical preparations and biological fluids, and satisfactory results were obtained. J. Clin. Lab. Anal. 21:213–219, 2007. © 2007 Wiley‐Liss, Inc.