applicants have produced a chromophore and a polymer that are highly sensitive to the presence of various agents , including organophosphates , pesticides , neurotoxins , metal ions , some explosives , and biological toxins . the detection is accomplished by detecting a change in the fluorescence characteristics of the chromophore or polymer when in the presence of the agent to be detected . the chromophore and polymer may be incorporated into sensors of various types , and they are adaptable for potential field use in areas where detection of these types of agents is desired .