In the first part of this thesis, the interaction of ds-DNA and sudan II dye was iected. For this purpose, pencil graphite electrode (PGE) and differential pulse voltammetry (DPV) technique were used. Using adsorptive stripping voltammetry, ds-DNA in acetate buffer solution was immobilized on the surface of the electrode. Furthermore, using DPV method, guanine and adenine signals after interaction of ds-DNA and sudan II were achieved. Under the optimum condition, with following the guanine and adenine signals, a linear dynamic range (LDR) between 0.5-6.0 µg mL -1 was achieved. The limit of detection (LOD) based on guanine and adenine signals were 0.43 and 0.48 µg mL -1 respectively. In order to investigate the mechanism of interaction, DPV and UV-vis methods were used. These investigations showed that the type of interaction is intercalation. Finally, the effect of interference species was investigated and the amount of sudan II in chili and ketchup souses were determined. In the second section of this thesis, the amount of sudan II was determined using DPV method and PGE. Using this method, LDR between 0.0015-3.0000 µg mL -1 and LOD 0.70 ng mL -1 were achieved. In second stage of this investigation, interaction between amitrole and ds-DNA using differential pulse voltammetry (DPV) technique were used. Under the optimum condition, LDR between 0.025-2.400 ng mL -1 and LOD 0.017 ng mL-1 were achieved. In the third section, ds-DNA damage due to Cr(VI)/GSH/H 2 O 2 was investigated. In order to optimize the parameters and ds-DNA damage iections, DPV method and PGE were used. In order to follow the ds-DNA damage, methylene blue as an electroactive probe was used. To investigate the amount of ds-DNA damage, the ratio of MB signal before and after damage was iected. Finally the time constant of ds-DNA damage was calculated. In the fourth section, ds-DNA damage due to catechol in presence of metal ions was investigated. In order to investigate the ds-DNA damage, electrochemical impedance spectroscopy (EIS) method and modified PGE were used. To follow the ds-DNA damage, modified electrode was immersed in solution containing metal ions and impedance spectra of electrode before and after ds-DNA damage were recorded. In the final stage of this investigation, the ds-DNA damage due to mitomycine C (MMC) was investigated. In order to investigate the damage, the ds-DNA damage due to reduced MMC and activated MMC in acidic solution were studied. Furthermore different parameters such as pH, time of interaction, concentration of MMC and applied potential were inspected.
