Simultaneous and selective electrochemical sensing of methotrexate and folic acid in biological fluids and pharmaceutical samples using Fe3O4/ppy/Pd nanocomposite modified screen printed graphite electrode

The purpose of this study was to fabricate an electrochemical sensor for the detection of methotrexate and folic acid based on a screen-printed graphite electrode (SPGE) modified with prepared iron oxide (Fe3O4)/polypyrrole (ppy)/Palladium (Pd) nanocomposite. Transmission electron microscopy (TEM), energy-dispersive X-ray spec-troscopy (EDX), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR) techniques were employed to characterize the Fe3O4/ppy/Pd nanocomposite. The produced modifier was used to induce a remarkable electrocatalytic impact relative to the oxidation of methotrexate, which caused the potential peak shift to a less positive amount (from 800 mV to about 500 mV) and improved the peak current (from 5.3 mu A to about 16 mu A). Methotrexate peak current was linearly dependent on its concentration from 0.03100.0 mu M and the limit of detection (LOD) was estimated at 7.0 nM. The methotrexate and folic acid were co-detected by the proposed sensor. The experimental results indicated that the oxidation peaks of methotrexate and folic acid were separated about 200 mV in phosphate buffer solution (PBS) at pH 7.0. Fe3O4/ppy/Pd/SPGE was successfully able to detect methotrexate and folic acid in pharmaceutical and biological samples with excellent recovery.

Automated summary

An electrochemical sensor was successfully fabricated using a modified screen-printed graphite electrode (SPGE) with Fe3O4/ppy/Pd nanocomposite for the detection of methotrexate and folic acid. The nanocomposite exhibited remarkable electrocatalytic activity for the oxidation of methotrexate, resulting in improved peak current and shifted peak potential. The proposed sensor showed excellent performance in detecting methotrexate and folic acid in pharmaceutical and biological samples.