An ultrasensitive and preprocessing-free electrochemical platform for the detection of doxorubicin based on tryptophan/polyethylene glycol-cobalt ferrite nanoparticles modified electrodes

[Display omitted] •An electrochemical sensor was designed for sensitive detection sensing of DOX.•The surface of the GCE electrode was modified by tryptophan/PEGylated-CoFe2O4 NPs.•This sensor was showed a specific manner towards DOX in unprocessed plasma samples.•PEGs provide an antifouling effect to stabilize the probe function. Doxorubicin (DOX) is an anticancer drug which can effectively inhibit the growth of cancer cells and aids the immune-mediated elimination of tumoral cells. Developing a new technique for analysis of DOX in clinical fluids is highly required. Here, a novel electrochemical sensor was designed using tryptophan (Trp)/(polyethylene glycol)PEGylated-CoFe2O4 nanoparticles to modify glassy carbon electrodes’ surface and was utilized to determine DOX in unprocessed human plasma samples. PEGylated-CoFe2O4 nanoparticles were coated on the surface of the glassy carbon electrode to provide the PEGylated-CoFe2O4/GCE probe. Under optimized conditions, the low limit of quantification (LLOQ) of the proposed sensor was 30 ng/mL and the linear ranges for the determination of DOX were 30 ng/mL to 1.0 μg/mL and 1.0 μg/mL to 5.0 μg/mL, respectively. PEG molecules provided an antifouling effect to prevent precipitation of the macromolecules on the surface of the fabricated electrode. Obtained results indicated that the suggested electrochemical sensor can be utilized for specific and sensitive determination of DOX in plasma samples.