Aniline was distilled before use. The platinum working electrode was first polished thoroughly with successive alumina slurries particle size of 1.0, 0.3, and 0.05 mm, and then rinsed with distilled water after each polishing step followed by
10 min sonication with ethanol and then water. The polyaniline (0.2M aniline in 1.0M HCl degassed in argon for 10 min) was electrochemically deposited on the platinum electrode (200mV to þ1100mV at 50 mVs1 for 20 cycles). The PANImodified
electrode was rinsed with water before use. The modified electrode was used in subsequent biosensor fabrication