LAUSR

Biosensing of urea by a biosensor as a direct detection method at ambient temperature and pressure instead of chromatography leads to a significant reduction in processing costs. Amperometric biosensors based on urease immobilization on macroporous polypyrrole (MPPy) and pyrrole on the surface of a Pt electrode were developed. Applying cyclic voltammetry (CV), we demonstrated the synthesis of MPPy using monodispersed polystyrene spheres (460 nm) as a template. CV and chronoamperometric studies were conducted to evaluate the electrochemical current of the modified electrodes. For the electrode with polypyrrole (PPy), the biosensor response was linear in the range of 1.67–8.32 mM (R = 0.99). Sensitivity, detection limit, and response time of this biosensor were 0.0035 mA mM−1 , 2.57 mM, and ∼7 s, respectively. For the electrode with MPPy, the linear range was 0.5–10.82 mM (R = 0.99). For this biosensor, sensitivity, detection limit (S/N = 3), and response time were 0.0432 mA mM−1 , 0.208 mM, and ∼5 s, respectively. The modified biosensor with MPPy showed high stability and desirable selectivity for urea.