Electrochemical behavior of methylene blue at bare and DNA-modified silver solid amalgam electrodes

• Published in: Journal of solid state electrochemistry 2022-11, Vol.26 (11), p.2491-2499
• Main Authors: Svitková, Veronika, Vyskočil, Vlastimil
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Biosensors; Characterization and Evaluation of Materials; Charge transfer; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Electrochemical analysis; Electrochemical impedance spectroscopy; Electrochemistry; Electrodes; Energy Storage; Methylene blue; Nyquist plots; Original Paper; Physical Chemistry; Voltammetry
• ISSN: 1432-8488; 1433-0768
• DOI: 10.1007/s10008-022-05270-3

Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used for a voltammetric study of methylene blue (MB) at a mercury meniscus-modified silver solid amalgam electrode (m-AgSAE). Electrochemical impedance spectroscopy (EIS) was used for the verification and comparison of results. DPV offered sensitive detection of MB (in 0.1 mol L −1 phosphate buffer of pH 7.0) at both a bare and a DNA-modified silver amalgam electrode. MB gives a specific cathodic signal related to the reduction of this redox intercalator. This signal is significantly higher at the DNA-modified than at the unmodified silver amalgam electrode, which is in correspondence with the changes in charge transfer resistance values obtained from Nyquist plots. The concentration of double-stranded DNA (dsDNA) to form a layer (0.1 mg mL −1 ), the time of the dsDNA spontaneous immobilization on the surface of the electrode (1 min), the concentration of MB (1 × 10 −5  mol L −1 ), and the time of the accumulation of MB into the dsDNA layer (1 min) were optimized for further biosensor development and applications. Graphical abstract