A sensor for detecting an analyte in an environment includes a first reaction system including a first enzyme and a substrate for the first enzyme. The analyte inhibits the reaction of the substrate catalyzed by the first enzyme. The sensor further includes at least a second reaction system that reacts to produce a first detectable state when the first enzyme is inhibited. In some embodiments, the reaction of the first reaction system can produce a second detectible state, different from the first detectible state. Another sensor for detecting an analyte in an environment includes a first reaction system including a first enzyme or a first substrate for the first enzyme. In this embodiment, the analyte is either a substrate for the first enzyme or the first enzyme if the first reaction system includes the first substrate. Figure (1) illustrates reaction schematics of one embodiment of a sensor of the present invention for detecting nerve agents.