|United States Patent||3,904,373|
|Harper||September 9, 1975|
Indicators insolubilized by covalent bonding to inorganic carriers for indicating the hydrogen ion concentration, oxidation-reduction state or specific ion concentration in liquid media. Since the indicators are insoluble they do not contaminate the solution tested, and they may be used repeatedly in different media. They replace the well known indicator test papers which consists of a substrate dyed with an indicator. Methods of making the indicators are also provided.
|Inventors:||Harper; Gerald Bruce (Toronto, CA)|
|Filed:||October 26, 1973|
|Current U.S. Class:||422/425 ; 436/166; 436/169|
|Current International Class:||G01N 31/22 (20060101); G01n 029/02 (); G01n 031/00 (); G01n 033/00 ()|
|Field of Search:||252/408 23/253TP 424/7|
|3350175||October 1967||McConnaughey et al.|
"New Method Makes Possible Nonbleeding Indicator Paper", Chem. and Engin. News, Vol. 48, No. 10, p. 38 (Mar. 9, 1970). .
"Surface-Produced Alignment of Liquid Crystals", Kahn, F. J., et al., Proc. of The IEEE, Vol. 61, No. 7, pp. 823-828 (July 1973)..