Ammonia detection and measurement device

Abstract

There is disclosed an apparatus and method for detecting and measuring volatile acidic or basic components including ammonia, ammonium, or volatile amines (compound) in a gas or liquid state fluid. Specifically, the present invention provides a PTFE-carrier solid phase indicator film having an ammonia-sensitive indicator dye embedded therein, such that the dye moiety changes color or spectral properties upon exposure to the compound to be detected.

1 . A sensor composition for detecting and measuring volatile acidic or basic compounds in a gas or liquid state fluid, comprising an ammonia-sensitive indicator dye having measurable spectral characteristics immobilized in or on a polytetrafluoroethylene (PTFE) solid substrate, whereby exposure to a volatile acidic or basic compound causes a change in spectral characteristics of the ammonia-sensitive indicator dye. 
     
     
         2 . The sensor composition of  claim 1  wherein the volatile acidic or basic compound is selected from the group consisting of hydrochloric acid, ammonia, ammonium, volatile amines, glacial acetic acid, and combinations thereof. 
     
     
         3 . The sensor composition of  claim 2  wherein the volatile amines are trimethylamine, dimethylamine, or combinations thereof. 
     
     
         4 . The sensor composition of  claim 1  wherein the PTFE solid substrate is in the form of a gas-permeable film. 
     
     
         5 . The sensor composition of  claim 1  wherein the ammonia-sensitive indicator dye is selected from the group consisting of bromophenol-blue, bromocreosol green, thymol blue, methyl crystal purple, chlorophenol red, tetraphenylporphyrin (H 2 TPP), and combinations thereof. 
     
     
         6 . The sensor composition of  claim 1  wherein the solid substrate is particulate PTFE and the sensor composition is suspended in a paste or paint solution for application onto a surface. 
     
     
         7 . A method for detecting and measuring volatile acidic or basic chemical compounds in a gas or liquid state fluid, comprising:
 (a) placing a sensor composition in a environment for detecting volatile acidic or basic chemical compounds, wherein the sensor composition comprises an ammonia-sensitive indicator dye having measurable spectral characteristics, immobilized in or on a solid substrate;   (b) determining the amount of volatile acidic or basic chemical compound present by measuring spectral change in the wavelengths of light (electromagnetic radiation) that are absorbed or emitted by the ammonia-sensitive indicator dye, or by observing a color change.   
     
     
         8 . The method of  claim 7  wherein the volatile acidic or basic chemical compound is selected from the group consisting of ammonia, ammonium, volatile amines, glacial acetic acid, and combinations thereof. 
     
     
         9 . The method of  claim 7  wherein the presence of ammonia, ammonium, or volatile amines present on the sensor composition is determined via a fiberoptic probe placed on the sensor composition. 
     
     
         10 . The method of  claim 7  wherein the absorbance or luminescent measurement of spectral change is determined with a spectrophotometer.