A novel sensitive DNA–biosensor for detection of a carcinogen, Sudan II, using electrochemically treated pencil graphite electrode by voltammetric methods

A simple and inexpensive methodology was used to develop a novel electrochemical sensor for the determination of Sudan II. The interaction of Sudan II with salmon sperm ds-DNA on the surface of salmon sperm ds-DNA-modified pencil graphite electrode (PGE) and in solution phase was studied, using differential pulse voltammetry. The difference between adenine and guanine signals of the ds-DNA after and before interaction with Sudan II was directly proportional to Sudan II concentration, which used for quantitative inspections. Using PGE, a linear calibration curve (R2 = 0.9958) was observed with 0.5–6.0 μg mL−1 Sudan II. Furthermore, the LOD of 0.4 μg mL−1 and linear range between 0.5 and 4.0 μg mL−1 were achieved in solution phase. In the second part, Sudan II was determined on a pretreated pencil graphite electrode by means of adsorptive stripping differential pulse voltammetry. The peak current was linearly dependent on Sudan II concentration over the range of 0.0015–0.30 μg mL−1, with a detection limit of 0.00007 μg mL−1 Sudan II. Both ds-DNA-modified PGE and PPGE were applied to analyze Sudan II in real samples.