Economical Approach for Determination of Kojic Acid by Nanostructured Ionic Liquid-Based Carbon Paste Sensor

An economical and sensitive nanostructured sensor based on carbon paste electrode (CPE) for the determination of kojic acid (KA) was developed in the current work. The applied CPE was modified with 1-butyl-3-methylimidazolium tetrafluoroborate (1B3MITFB) as a conductive binder and NiO nanoparticles (NiO/NPs). The proposed modified ionic liquid-based carbon paste electrode showed satisfactory concentration range and lower detection limit of 5.0-600 mu M and 0.8 mu M at phosphate buffer pH 6.0, respectively. An acceptable reproducibility with a satisfactory analytical characteristic was observed for the proposed sensor in the presence of common interfering compounds. The observed irreversible oxidation behavior of KA at the surface of the NiO/NPs/1B3MITFB/MCPE was controlled under the diffusion step and the diffusion coefficient (D) at the mass transport limited rate found to be 2.3 x 10(-4) cm(2) s(-1). According to the slope of the Tafel plot, the value of 0.625 was calculated for the electron transfer coefficient (alpha). The acquired data from electrochemical impedance spectroscopy studies confirmed that the presence of NiO NPS and 1B3MITFB as a conductive binder resulted in a significant increase in the electro-oxidation signal of KA. The value of 12.3 k omega for the R-ct of unmodified CPE decreased to the value of 1.7 k omega for the modified electrode. The obtained results revealed that the proposed modified ionic liquid-based carbon paste electrode could be applied successfully for the analysis of trace amounts of KA in biological samples such as blood serum, urine, and pharmaceutical samples such as liposome carriers containing KA as well as food samples such as vinegar. The synthesized NiO nanoparticles were characterized using XRD and EDAX analyses. The morphology of NiO/NPs is further characterized by SEM. Electro-oxidation of kojic acid.