Potassium-doped graphene for simultaneous determination of nitrite and sulfite in polluted water

Potassium (K) doping plays a critical role in adjusting the electronic properties of carbon materials. In this work, K-doped graphene, as a new electrode material, was used to modify glassy carbon electrode (GCE) for the simultaneous determination of nitrite (NO2-) and sulfite (SO32-) under neutral conditions. The advantages of K-doped graphene/GCE are illustrated from comparison with the graphene/GCE, K-doped multi-walled carbon nanotubes (MWNTs)/GCE, MWNTs/GCE, graphite/GCE and bare/GCE for electrocatalytic and sensing applications. It exhibited a linear response over the concentration range from 0.5 mu m to 3.9 mM, with a detection limit of 0.2 mu M (S/N = 3) for NO2- and a corresponding linear range of 2.5 mu M to 10.3 mM, with a detection limit of 1.0 mu M (S/N = 3) for SO32-. The proposed sensor could be successfully applied in the simultaneous detection of residual NO2- and SO32- in polluted water accurately and precisely. (C) 2012 Elsevier B.V. All rights reserved.