Development of novel Mn-zeolite/graphite modified Screen-printed Carbon Electrode for ultrasensitive and selective determination of folic acid

This paper reports the fabrication of a new, portable, and user-friendly zeolite-based sensor - the Mn-zeolite/ graphite modified Screen-printed Carbon Electrode (MnZG-SPCE) and its application in the highly-sensitive determination of folic acid (FA) by differential pulse voltammetry (DPV). The X-ray spectroscopy measurements proved the incorporation of Mn cations into the zeolite framework, whereas the SEM images and cyclic voltammograms provided intel about morphology and electrochemical properties of the modifying layer. The developed method for FA determination exhibited the linear response from 0.004 to 0.99 mg L-1 (R = 0.9998) and the limit of detection (LOD, S/N = 3) of 1.3 ug L-1 (2.9 nM). The major improvement was observed in the sensitivity equaled 6.93 mu A L mg-1, which translates into a higher resolution, thus the possibility to detect small changes in FA concentration. Employment of MnZG-SPCE in the determination of FA in pharmaceuticals delivered reliable results, as verified by the reference method (UV-Vis spectroscopy).