Novel amperometric sensors for nitrite detection using electrodes modified with PEDOT prepared in ionic liquids

Novel amperometric sensors based on poly-3,4-ethylenedioxythiophene (PEDOT) were prepared and characterized for nitrite detection. An experimental matrix of two substrate materials (glassy carbon and gold) and four electrolytes used for preparation of electrodes (water, acetonitrile, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide) were investigated for the preparation of the sensors. The obtained films were characterized using scanning electron microscopy, cyclic voltammetry, amperometry, and electrochemical quartz crystal microbalance. Both glassy carbon and gold electrodes modified with PEDOT showed excellent electrocatalytic activity toward nitrite oxidation. An improved influence of the electrodes prepared in ionic liquids could be observed for the detection of nitrite, expressed by higher electrocatalytic activity and better sensitivities. The sensors showed good stability, while only weak interferences with selected cations, anions, and small biomolecules were detected.