Electrochemical determination of purine and pyrimidine bases using a 1,10-phenanthroline–Fe3O4 nanoparticles–graphene oxide–chitosan nanocomposite

Abstract

A 1,10-phenanthroline–Fe₃O₄ nanoparticles–graphene oxide–chitosan nanocomposite (Phen–Fe₃O₄ NPs–GO–Chi) was fabricated and used to modify a glassy carbon (GC) electrode. The modified surface of the electrode was characterized by field emission-scanning electrochemical microscopy. Then, the prepared electrode was used as a sensor for simultaneous determination of purine and pyrimidine bases in DNA. The Phen–Fe₃O₄ NPs–GO–Chi composite modified electrode showed excellent response toward guanine (G), adenine (A), thymine (T) and cytosine (C). The sensor displayed higher effective surface, an appropriate peak-to-peak separation, and a larger peak current compared to the bare electrode. The evaluated detection limits of G, A, T, and C concentrations are 12, 4, 22, and 9 μM over the concentration range of 15–500, 15–400, 40–1000 and 40–1400 μM, respectively. In addition, the results show that the modified electrode is stable for 7 days and has good repeatability and interfering molecules and ions have no significant effect on peak current. The proposed method was successfully applied for the determination of purine and pyrimidine bases in a fish DNA sperm sample as a real sample.