Amperometric nitrite sensor based on a glassy carbon electrode modified with electrodeposited poly(3,4-ethylenedioxythiophene) doped with a polyacenic semiconductor

The paper describes an electrochemical nitrite sensor based on the use of a nanocomposite consisting of poly(3,4-ethylenedioxythiophene) (PEDOT) doped with polyacenic semiconductor (PAS), a quasi-graphene carbon material. The composite possesses a large specific surface area and a large number of active sites. It shows high catalytic activity towards the oxidation of nitrite. Such activity is not observed in the individual components. Nitrite provides a well-defined oxidation peak at 0.80 V (vs. Ag/AgCl) at a pH value of 7.4. The influence of many possible ionic interferents was found to be negligible. In addition, the oxidation peaks of dopamine hydrochloride, ascorbic acid, uric acid and nitrite are well separated from each other. Under optimized experimental conditions, anodic peak currents are linearly related to nitrite concentrations in the range from 0.3 mu M to 6.6 mM, and the detection limit is 98 nM (at an S/N ratio of 3). The sensor was used to quantify nitrite in (spiked) tap water and sausage samples, where it gave acceptable recoveries.