Development of novel electrochemical urea biosensor with ferrocene appended polycarbazole

An innovative enzymatic electrochemical urea biosensor has been developed based on a Nafion/Polyaniline (Nf/PANI) composite mechanism combined with ferrocene-appended polycarbazole (FAPCz). Structural and morphological characterisations of the ferrocene-carbazole monomer (FCM) and FAPCz were performed with FTIR, NMR, MALDI-TOF, TGA, SEM-EDX, and XRD analyses. After chemical characterization, the FAPCz was integrated into a Nf/PANI-modified glassy carbon electrode, followed by immobilization of urease (Urs) via glutaraldehyde crosslinking. Optimization studies revealed that the FAPCz provided a significant enhancement in electron transfer and catalytic efficiency. Differential pulse voltammetry (DPV) and cyclic voltammetry (CV) were applied to assess biosensor production and performance. The GCE/Nf/PANI/FAPCz/Urs biosensor demonstrated a linear detection range of 0.62-60.6 mu M, with a detection limit of 0.55 mu M and a quantitation limit of 1.66 mu M using DPV. The sensor demonstrated good selectivity against common interfering ions and bioanalytes, high reproducibility (RSD < 2.00 %), and long-term stability. In addition, the biosensor demonstrated applicability for real soil and water samples, with its analytical accuracy and reliability confirmed by recovery tests and GC-MS analyses.