Determination of isoniazid by a copper-based metal-organic frameworks/carbon nitride quantum dots modified pencil graphite electrode as a highly sensitive and selective sensor

Abstract In this work, a particular electrochemical sensor for analysis of isoniazid (INZ), a tuberculostatic drug, was presented. The electrotreated pencil graphite electrode (ETPGE) was modified by a nanocomposite of the copper-based metal-organic frameworks (Cu-MOFs)/carbon nitride quantum dots (CNQDs), Cu-MOFs/CNQDs/ETPGE, and was utilized for electroanalysis of INZ. Physicochemical characteristics and analytical performance of the Cu-MOFs/CNQDs/ETPGE were investigated through relevant instruments. Compared with bare PGE, ETPGE, CNQDs/ETPGE, and Cu-MOFs/ETPGE, the Cu-MOFs/CNQDs/ETPGE showed strong electrocatalytic activity for oxidation of the INZ and exhibited a well-defined anodic peak at a low potential of +0.364 V versus Ag/AgCl in pH 7.0 medium due to its high specific surface area, high conductivity and fast charge transfer ability. The experimental results demonstrated that the Cu-MOFs/CNQDs/ETPGE has a promising potential candidate as a stable and efficient electrochemical sensor for determination of INZ. Under the optimized experimental conditions, the designed sensor presented a wide linear response range for INZ concentration (0.1 μM to 65.0 μM) with a low practical detection limit (0.0675 μM), limit of quantification (LOQ) (0.225 μM), high sensitivity (1.507 A mol−1 L cm−2) and excellent repeatability in differential pulse voltammetry. Further, the suggested method was employed successfully for determination of INZ in drug and biological samples with satisfactory recovery values.