A new electrochemical sensor based on porous silicon supported Pt–Pd nanoalloy for simultaneous determination of adenine and guanine

• A new nanocomposite was synthesized by loading of Pt–Pd nanoparticles on porous silicon.
• Pt–Pd/porous silicon nanocomposite was incorporated in carbon nanotube paste electrode.
• The modified electrode was used for simultaneous determination of adenine and guanine.
• Voltammetric method was used for quantitative detection of adenine and guanine.
• Adenine and guanine could be detect as low as 30 and 20 nmol L−1, respectively.

A new nanocomposite (porous silicon supported Pt–Pd nanoalloy) was prepared and used as an electrode material for simultaneous determination of adenine and guanine. For this purpose, Pt–Pd nanoparticles were supported on porous silicon microparticles by a simple galvanic reaction in a HF solution. The nanocomposite was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction spectroscopy and cyclic voltammetry. Incorporation of Pt–Pd/porous silicon (Pt–Pd/PSi) nanocomposite in the carbon nanotube paste electrode (CNTPE) increased the oxidation peak currents (about 3 folds) and reduced the overpotential of adenine and guanine. The effects of different parameters such as pH, accumulation time, accumulation potential, and potential scan rate on the sensitivity were investigated. The new developed sensor was then employed for simultaneous determination of purine bases with linear ranges of 0.10–10.0 μmol L−1, using differential pulse voltammetry. Detection limits of 30 and 20 nmol L−1 were achieved for adenine and guanine, respectively. Individual determination of purine bases were performed by amperometric technique with a linear range of 60.0 nmol L−1–55.0 μmol L−1 and detection limit of 30 nmol L−1 for adenine, while the linear range of 40.0 nmol L−1–53.4 μmol L−1 with detection limit of 10 nmol L−1 was achieved for guanine. Finally, the proposed electrochemical sensor was employed to determine adenine and guanine in single-strand deoxyribonucleic acid (ssDNA) samples.

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