Folic acid electrocatalytic oxidation on the carbon electrode surface modified with ferrocenyl grafted polymethylhydrosiloxane

Abstract

In this research, we synthesized ferrocenyl‐grafted polymethylhydrosiloxane (PMHS) through a hydrosilylation reaction between 3‐butenylferrocene and PMHS. The incorporation of the ferrocenyl derivative into the polymer backbone imparted electrochemical properties to the modified polymer. The modification of the polymer was confirmed by various techniques, including FT‐IR, 1H NMR, and UV–Vis spectroscopy. To prepare the new ferrocenyl polymer, we utilized cross‐linking agents, namely terephthaldehyde (TPA) and fresh egg white (FEW). The resulting polymer was drop‐coated onto a glassy carbon electrode (GCE) surface (5 μL). Electrochemical impedance spectroscopy (EIS) analysis confirmed the successful immobilization of the polymer on the GCE surface. Under physiological pH conditions (pH = 7), the Fc/Fc + couple facilitated the oxidation of folic acid (FA) at a potential of 0.40 V vs. the Ag/AgCl reference electrode. The GC/PMHS‐Fc/(TPA + FEW) electrode exhibited excellent stability, retaining 89% and 90% of its electrocatalytic activity after 500 cycles and 30 days of storage in a refrigerator, respectively. Thus, it shows promising potential for the determination of FA in biological fluids. The ferrocene‐modified electroactive polymer demonstrated satisfactory linear ranges for FA determination (5–150 μM) and a low limit of detection (LOD = 36 nM). These results highlight the effectiveness of the new polymer in detecting FA in biological samples.