Figure 4: The time resolved fluorescence decay profiles of HSA in absence and presence of 5-FU in Tris–HCl buffer of pH 7.4 various concentration of λex=280 nm and λem=345 nm. HSA concentration was fixed at 1 × 106 M. In (1–3) 5-FU concentrations were of 0, 10 and 80 × 106 M.