A Novel Electrochemical Sensing Platform Based on Zn-Co ZIFs/GO Nanocomposite and Ionic Liquid for Sensitive Determination of Methotrexate in the Presence of Calcium Folinate

Herein, the Zn-Co zeolitic imidazolate frameworks/graphene oxide (Zn-Co ZIFs/GO) nanocomposite and an ionic liquid (IL) were used to modify carbon paste electrode (CPE) for the design and preparation of an electrochemical sensing platform for voltammetric determination of methotrexate in the presence of calcium folinate. The facile synthesis of Zn-Co ZIFs/GO nanocomposite has been performed at ambient temperature. The utilization of prepared Zn-Co ZIFs/GO nanocomposite along with IL in modification of CPE facilitates electron transfers, enhances the effective surface areas and electrical conductivity, and thereby improves the performance of the designed sensor towards the oxidation of methotrexate. The investigations of cyclic voltammetry showed a significant improvement in the current response of methotrexate (13.0 μA) was achieved at lower over-potential (740 mV) using Zn-Co ZIFs/GO-ILCPE than that of unmodified CPE, Zn-Co ZIFs/GO-CPE, and ILCPE. Differential pulse voltammetry measurements of the Zn-Co ZIFs/GO-ILCPE response under the optimum conditions displayed a linear detection range for 0.05 to 340.0 μM methotrexate with a detection limit (LOD) of 0.01 ± 0.001 μM (S/N = 3). The Zn-Co ZIFs/GO-ILCPE sensor showed demonstrated well-resolved voltammetric peaks corresponding to the oxidation of methotrexate and calcium folinate, proving the successful determination of methotrexate in the presence of calcium folinate.