Bismuth-nanocomposites modified SPCEs for non-enzymatic electrochemical sensors

We present newly developed electrochemical sensors based on screen-printed carbon electrodes functionalized with HO-BiONO3, polyethylene glycol coated HO-BiONO3, and Bi5O7NO3. The performance of these sensors has been studied by cyclic voltammetry experiments and compared in terms of the kinetic rate constant, the sensitivity, and the limit of detection. The polyethylene glycol coated HO-BiONO3 sensor was found with higher oxidation peak current, lower oxidation peak potential, and assured a faster paracetamol reaction due to a higher kinetic rate constant of 42.0 ± 9.8 ms-1. This sensor also possessed lesser peak-to-peak separation (ΔEp) of 243 ± 10 mV with a higher chance of reversible reaction compared to other developed sensors. The polyethylene glycol coated HO-BiONO3 sensor also registered a sensitivity of 43.50 ± 0.54 μA/mM with a relative standard deviation of 1.24 %, which is more than double compared to the bare screen-printed electrode with a limit of detection of 2.24 ± 0.03 μM (R2 = 0.998, n=3). HO-BiONO3 and Bi5O7NO3 sensors also performed much better with slightly higher kinetic rate constant and higher sensitivity than the bare screen-printed electrode sensor.