One aspect of the present invention relates to a method for detecting the presence of an analyte by comparing the conductivity of a mixture containing an analyte and a sensor to the conductivity of the sensor in the absence of analyte. In certain embodiments, the sensor of the present invention consists of a complexing domain comprising a metal ion and a complexing agent and a conducting polymer, wherein the redox potential of the metal ion is similar to the redox potential of the conducting polymer. In one preferred embodiment, the presence of nitric oxide is detected by measuring the conducting change of a sensor comprising poly N,N'-ethylenebis(salicylidenimine) and cobalt. The poly N,N'-ethylenebis(salicylidenimine) cobalt sensors of the present invention are not adversely effected by the presence of water or oxygen.