In the present study, a new biosensor for 5-Fluorouracil was described using modified goldelectrode and Fast Fourier transform square wave voltammetry (FFT SWV). Calf thymus DNAimmobilization was on a gold electrode decorated with polyaniline and gold nanoparticles. Theelectrochemical characteristics of the electrodes were investigated by cyclic voltammetry, andelectrochemical impedance spectroscopy. After interaction DNA with the analyte, a dramaticdecline in [Fe(CN)6]/[Fe(CN)6]]3-/4- signal was observed which could be used as the signal. Theimportant parameters of the detection system, such as, pH were optimized. The linear dynamicrange of the biosensor was1×10-9 to 1×10-6 M (r2=0.996) limits of detection of2.5×10−10 M. In addition to the wide linear range response, the proposed method demonstratedacceptable sensitivity, repeatability and long-term stability. Future experiments could be performedto examine several other effective factors so as to decrease the influence of the environment andinvestigate its application to FFTSWV detection. پرونده مقاله