Karimi-Maleh, HassanTahernejad-Javazmi, FahimehAtar, NecipLutfi, MehmetGupta, Vinod KumarEnsafi, Ali A.2025-03-232025-03-2320150888-5885https://doi.org/10.1021/ie504438zhttps://hdl.handle.net/11486/5940A novel and sensitive biosensor employing immobilized DNA on a pencil graphite electrode modified with polypyrrole/functionalized multiwalled carbon nanotubes for the determination of 6-mercaptopurine (6-MP) is presented. In the first step, we modified the pencil graphite surface with polypyrrole and functionalized multiwalled carbon nanotubes (MWCNT/COOH). The developed electrode was characterized by scanning electron microscopy, atomic force microscopy, reflectionabsorption infrared spectroscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. In the other step, we used decreases in the oxidation responses of guanine and adenine as a sign of the interaction of 6-MP with salmon sperm double-stranded DNA using differential pulse voltammetry. The signal of guanine oxidation was linear with respect to the 6-MP concentration in the range of 0.2-100 mu mol L-1 with a detection limit of 0.08 mu mol L-1. The modified electrode was utilized for the determination of 6-MP in real samples.eninfo:eu-repo/semantics/closedAccessSensitive Voltammetric SensorPaste ElectrodeNanoparticlesNanocompositeGlutathioneQuercetinArticle54143634363910.1021/ie504438z2-s2.0-84927944336Q1WOS:000353177800012Q2