Photochemically induced fluorimetry, UV-Vis spectroscopy, and voltammetry on the DNA/MWCNT/GCE to investigate the interaction of sulfamethazine with DNA: determination of DNA

摘要

In this study the interaction of sulfamethazine with DNA was investigated by photochemically induced fluorescence, UV-Vis spectroscopy, and voltammetry on the glassy carbon electrode modified with DNA-multiwalled carbon nanotubes composite (DNA/MWCNT/GCE). Photochemically induced fluorescence was based on UV irradiation of sulfamethazine in the presence of sodium sulfite as sensitizing reagent for a fixed time. The photochemically induced fluorescence emitted by sulfamethazine at 348 nm could be quenched in B-R buffer solution (pH 7.0, 0.04 mol dm(-3)) when DNA was added, which indicating the interaction of sulfamethazine with DNA. The mechanism of fluorescence quenching was a static quenching according to the Stern-Volmer plot. Furthermore, interaction of sulfamethazine with DNA on DNA/MWCNT/GCE, showing a decrease of peak current of the sulfamethazine oxidation without significant potential shift. The UV spectroscopic data confirmed the intercalative interaction by hypochromism and bathochromic shift of 242 nm absorbance band. The binding constants of the interaction of sulfamethazine with DNA were obtained by all three methods in the range 1.21 x 10(3)-2.2 x 10(3) dm(3) mol(-1). Finally, photochemically induced fluorescence was successfully applied for determination of DNA with satisfactory linearity ranges (0.7-8.1 and 13.1-65.0 mg dm(-3)), admissible limit of detection (0.43 mg dm(-3)), and good repeatability (0.29 %).