This research introduced a sensitive and novel electrochemical DNA-based biosensor for the measurement of naringin and glutathione using differential pulse voltammetry (DPV). This biosensor was based on ds-DNA / poly (diallyldimethylammonium chloride) (PDDA)/ multiwall carbon nanotubes (MWCNTs) modified pencil graphite electrode (PGE) for monitoring the guanine and adenine oxidation signals. The surface morphology of these modified electrode was studied with scanning electron microscopy (SEM). The results showed that the chemically modified electrode exhibited considerable sensitivity. Different parameters on the response of measurement of naringin and glutathione such as concentration of ds-DNA, time of interaction between ds-DNA and mentioned materials, type of buffer and other parameters are optimized. Under the optimized conditions using differential pulse voltammetry two linear segments were obtained for naringin. First segment from 0.058 to 5.80 mg.L-1 and the second one was from 5.80 to 580.0 mg.L-1, with a detection limit of 0.0103 mg.L-1. The relative standard deviation of five repeated measurements of 5.80 mg.L-1 naringin was 3.78 and 4.23 % for oxidation signal of guanine and adenine, respectively. The interference of foreign substances was investigated. This electrochemical biosensor was applied to analyze naringin in various citrus juices.
Finally, the determination of glutathione also have been studied at the modified pencil graphite electrode with dsDNA/MWCNTs-PDDA using DPV. After interaction of dsDNA with glutathione by using of increscent of oxidation signals of guanine and adenine was measured glutathione. The detection limit was obtained 0.0071 mg.L-1. The proposed method was used for determination of glutathione in plasma and urine.
Naringin, Glutathione, Pencil Graphite Electrode, Multiwall Carbon Nanotubes, PDDA, Differential Pulse Voltammetry