Heat sensitive liquid chemical agent and pesticide detector and method of using

Abstract

The device of this invention is used to detect small quantities of liquid emical agents in certain pesticides on the basis of the heat reaction between the liquid agent and a chemical oxidant such as sodium or calcium hypochlorite. The detecting device consists of a thin film of resistance heat sensitive element on top of which porous or fibrous substrate material is mounted. This substrate is impregnated with the oxidant material. As a liquid agent contacts substrate it permeates through the substrate and reacts with the oxidant and generates heat. The output volume from the thin film resistance element increases correspondingly. The time from agent contact until this signal is observed as tested is less than one (1) second. The method is directed to the contacting of the liquid agent against the surface, wherein it permeates through the substrate and reacts with the oxidant and generates heat which change in heat is detected by the detecting device.

What is claimed is: 
     
       1. A device for detecting presence of chemical agents, said agents comprising of organic phosphate materials contacting said device, the device comprising: a base means made of an electrically and thermally insulative material, said base means having an electrode having a defined dimension of height and an upper surface;   an electrode made of a layer of platinum material deposited on the upper surface of said base means; the thickness of said layer being relatively small compared to the height of said base means;   a porous material, embedded with an oxidizing agent, said material vapor deposited over the upper surface of said base means, covering over said electrode;   means for causing a constant current of approximately 4 milliamps direct current to flow through said electrode when the device is in use;   means for constantly measuring the voltage that appears across said electrode, such voltage occurring because of said current flowing in said electrode;   whereby when liquid droplets of organic phosphate chemical agents are deposited onto said porous material, they react with said oxidizing agent causing heat release, whereupon a heating of said electrode occurs within one second which heating leads to a current fluctuation in said electrode, such current fluctuation causes a change in the voltage being measured across the electrode whereupon such voltage change is indicative that such deposited droplets had been chemical agents comprising organic phosphate materials.   
     
     
       2. The device as in claim 1 whereby said base means is made of pyrex material. 
     
     
       3. The device as in claim 2 whereby said porous material comprises a polyethelene substrate. 
     
     
       4. The device as in claim 1 whereby the oxidizing agent is calcium hypochlorite.