Prussian blue based impedimetric urea biosensor

Abstract In this research an impedimetric urea biosensor was formed by modifying a fluorine doped tin oxide coated glass slide (glass/FTO) with a layer of PB (glass/FTO/PB), which was further stabilized in ammonium ion-containing medium, and immobilizing urease (glass/FTO/PB/urease) with vapor of glutaric aldehyde. Fast Fourier transform electrochemical impedance spectroscopy (FFT-EIS) investigation of the glass/FTO/PB/urease-based biosensor in urea-containing buffer solution indicated that the glass/FTO/PB/urease-based biosensor exhibits good sensitivity to urea (2.55 Ω cm2 mM−1) and a range of linearly detectable concentrations of urea from 0.1 mM to 5.4 mM (R2 = 0.992). To determine the optimal conditions of PB layer stabilisation, the influence of acidity of NH4Cl solution on the efficiency of cyclic voltammetry-based stabilization of PB layer was investigated in this research as well.