Fast and sensitive determination of doxorubicin using multi-walled carbon nanotubes as a sensor and CoFe₂O₄ magnetic nanoparticles as a mediator

Spinel-structured cobalt ferrite (CoFe₂O₄) magnetic nanoparticles (MNPs) were synthesized by a modified chemical coprecipitation method. The MNPs were characterized by X-ray diffraction, field emission scanning electron microscopy and Fourier transform infrared spectroscopy. Then, a doxorubicin sensor was constructed by modifying a carbon paste electrode with multi-walled carbon nanotubes (MWCNTs) and the MNPs. Under optimized conditions, the differential pulse voltammetric response of the modified electrode at a working voltage of 0.46 V vs. Ag/AgCl is related to the concentration of doxorubicin in the 0.05–1150 nM range, with a 10 pM detection limit at a signal-to-noise ratio of 3. (author)