All-solid-state nitrate-selective electrode and its application in drinking water

An all-solid-state nitrate-selective electrode with the implementation of graphene as the ion-to-electron transducer was reported. The charge-transfer process was examined by electrochemical impedance spectroscope and the hydrophobic nature of the graphene film was characterized via the potentiometric water layer test. The analytical performance of the nitrate-selective electrode was investigated by the determination of nitrate in drinking water. The obtained results showed that graphene can significantly facilitate the ion-to-electron transducer and prevent the formation of water layer between the ion-selective membrane and the graphene layer. The fabricated nitrate-selective electrode displayed a Nernstian slope of 57.9 mV per decade of nitrate concentration, a low detection limit of 3 × 10−5 M and a rapid response time (within 10 s) for concentration upon 10−4 M. The determination of real samples indicated that the constructed nitrate-selective electrode was capable of monitoring nitrate in drinking water, providing a handy alternative for routine analysis.