Electrochemical sensors for testing water

Abstract

An electrochemical sensor for the detection and analysis of an analyte in a solution is disclosed. The electrochemical sensor has an electrically non-conductive support; a plurality of electrodes on the support, each electrode having a first surface and an opposite second surface, said first surface facing towards the support and the second surface facing away from the support. The plurality of electrodes includes a reference electrode, a counter electrode, and a working electrode. The working electrode has a reagent composition containing a reagent for detecting an analyte applied directly to the second surface of the working electrode.

What is claimed is: 
     
         1 . A electrochemical sensor for the detection and analysis of analyte in a solution, said electrochemical sensor comprising:
 (i) an electrically non-conductive support;   (ii) a plurality of electrodes on the support, each electrode having a first surface and an opposite second surface, said first surface facing towards the support and the second surface facing away from the support, the plurality of electrodes comprising
 a. a reference electrode, 
 b. a counter electrode, and 
 c. a working electrode; and 
   (iii) a reagent composition containing a reagent for detecting an analyte applied directly to the second surface of the working electrode.   
     
     
         2 . The electrochemical sensor according to  claim 1 , wherein the electrode comprises one to eight working electrodes. 
     
     
         3 . The electrochemical sensor according to  claim 1 , wherein the reagent composition essentially completely covers the entire second surface of the working electrodes. 
     
     
         4 . The electrochemical sensor according to  claim 1 , wherein the reagent composition applied to the working electrode comprises a reagent for analyzing free chlorine. 
     
     
         5 . The electrochemical sensor according to  claim 4 , wherein the reagent composition comprises a redox indicator reagent, a buffer and a polymeric material. 
     
     
         6 . The electrochemical sensor according to  claim 5 , wherein the redox indicator reagent comprises an agent selected from the group consisting of p-phenylenediamine salts, N,N-diethyl-p-phenylenediamine sulfate salt, N,N-dimethyl-p-phenylenediamine sulfate salt, and N,N,N′N′-tetramethyl-p-phenylenediamine. 
     
     
         7 . The electrochemical sensor according to  claim 5 , wherein buffer comprises a phthalate buffer or a phosphate buffer. 
     
     
         8 . The electrochemical sensor according to  claim 5 , wherein the polymeric material comprises polyethylene glycol, sodium alginate, polyvinyl alcohol, or polyvinylpyrrolidone. 
     
     
         9 . The electrochemical sensor according to  claim 5 , wherein the redox indicator reagent comprises N,N-diethyl-p-phenylenediamine sulfate salt, the buffer comprises a phosphate buffer and the polymeric material comprises polyethylene glycol. 
     
     
         10 . The electrochemical sensor according to  claim 1 , wherein the reagent composition applied to the working electrode comprises reagent for analyzing total chlorine. 
     
     
         11 . The electrochemical sensor according to  claim 10 , wherein the reagent composition comprises a metal halide salt as the reagent, a buffer and a polyelectrolyte polymer. 
     
     
         12 . The electrochemical sensor according to  claim 11 , wherein the metal halide salt comprises potassium bromide. 
     
     
         13 . The electrochemical sensor according to  claim 11 , wherein the buffer comprises a phthalate buffer or a phosphate buffer. 
     
     
         14 . The electrochemical sensor according to  claim 11 , wherein the polyelectrolyte polymer comprises sodium alginate, polyvinyl alcohol, or polyvinylpyrrolidone. 
     
     
         15 . The electrochemical sensor according to  claim 11 , wherein the metal halide comprises potassium bromide, the buffer comprises potassium hydrogen phthalate, and the polyelectrolyte comprises sodium alginate. 
     
     
         16 . The electrochemical sensor according to  claim 1 , wherein the reagent composition applied to the working electrode comprises a reagent for analyzing water hardness. 
     
     
         17 . The electrochemical sensor according to  claim 16 , wherein the reagent composition comprises reagent which is an indicator for calcium, a buffer and a polyelectrolyte polymer. 
     
     
         18 . The electrochemical sensor according to  claim 17 , wherein the reagent which is an indicator for calcium is selected from the group consisting of Alizarin Red, Alizarin Yellow CG, Alizarin Green, Alizarin Blue Black B, and Eriochrome Black T. 
     
     
         19 . The electrochemical sensor according to  claim 11 , wherein the buffer comprises a phthalate buffer, a phosphate buffer or an acetate buffer. 
     
     
         20 . The electrochemical sensor according to  claim 11 , wherein the polyelectrolyte polymer comprises sodium alginate, polyvinyl alcohol, or polyvinylpyrrolidone. 
     
     
         21 . The electrochemical sensor according to  claim 11 , wherein the reagent which is an indicator for calcium comprises Alizarin Red S, the buffer comprises potassium hydrogen phthalate, and the polyelectrolyte comprises sodium alginate. 
     
     
         22 . The electrochemical sensor according to  claim 1 , further comprising a plurality of electrical contacts, wherein each of the electrodes is electrically connected with a separate contact. 
     
     
         23 . The electrochemical sensor according to  claim 1 , wherein the reference electrode comprises a silver/silver chloride electrode, the counter electrode comprises a carbon electrode and the working electrode comprises a carbon electrode. 
     
     
         24 . The electrochemical sensor according to  claim 1 , wherein there are a plurality of working electrodes, wherein the working electrodes each have a reagent composition applied to the second surface of each working electrode, the reagent composition selected from the group consisting of a composition containing a reagent for detecting free chlorine, a composition containing a reagent for detecting total chlorine, a composition containing a reagent for detecting total chlorine, and a reagent composition for detecting water hardness and a reagent composition for detecting total alkalinity. 
     
     
         25 . The electrochemical sensor according to  claim 24 , wherein the plurality of working electrodes comprises two working electrodes, a first working electrode and a second working electrode, wherein the first electrode has a reagent composition containing a reagent for detecting free chlorine applied to the second surface of the first working electrode and the second working electrode has a reagent composition containing a reagent for detecting total chlorine applied to the second surface of the second working electrode. 
     
     
         26 . The electrochemical sensor according to  claim 25 , further comprising a third working electrode, and the third working electrode has a reagent composition for detecting water hardness applied to the second surface of the third working electrode. 
     
     
         27 . The electrochemical sensor according to  claim 26 , further comprising a fourth working electrode, and the fourth working electrode has a reagent composition for detecting water total alkalinity applied to the second surface of the fourth working electrode. 
     
     
         28 . The electrochemical sensor according to  claim 24 , the working electrode comprises two working electrodes, a first working electrode and a second working electrode, wherein the first electrode has a reagent composition for detecting water hardness applied to the second surface of the first working electrode and the second working electrode has a reagent composition for detecting total alkalinity applied to the second surface of the second working electrode. 
     
     
         29 . The electrochemical sensor according to  claim 25 , wherein the reagent composition containing a reagent for detecting free chlorine comprises N,N-diethyl-p-phenylenediamine sulfate salt, the buffer comprises a phosphate buffer and the polymeric material comprises polyethylene glycol and the reagent composition containing a reagent for detecting total chlorine comprises potassium bromide, potassium hydrogen phthalate, and sodium alginate. 
     
     
         30 . The electrochemical sensor according to  claim 26 , wherein the reagent composition containing a reagent for detecting free chlorine comprises N,N-diethyl-p-phenylenediamine sulfate salt, the buffer comprises a phosphate buffer and the polymeric material comprises polyethylene glycol, the reagent composition containing a reagent for detecting total chlorine comprises potassium bromide, potassium hydrogen phthalate, and sodium alginate; and the reagent composition for detecting water hardness comprises Alizarin Red S, potassium hydrogen phthalate, and sodium alginate. 
     
     
         31 . The electrochemical sensor according to  claim 27 , wherein the reagent composition containing a reagent for detecting free chlorine comprises N,N-diethyl-p-phenylenediamine sulfate salt, the buffer comprises a phosphate buffer and the polymeric material comprises polyethylene glycol; the reagent composition containing a reagent for detecting total chlorine comprises potassium bromide, potassium hydrogen phthalate, and sodium alginate; the reagent composition for detecting water hardness comprises Alizarin Red S, potassium hydrogen phthalate, and sodium alginate; and the reagent composition for detecting total alkalinity comprises manganese perchlorate and polyvinylpyrrolidone. 
     
     
         32 . A method of analyzing water, said method comprising:
 providing a sample of water containing an analyte to be measured;   providing, in a display device, an electrochemical sensor including,
 (i) an electrically non-conductive support; 
 (ii) a plurality of electrodes on the support, each electrode having a first surface and an opposite second surface, said first surface facing towards the support and the second surface facing away from the support, the plurality of electrodes including
 a. a reference electrode, 
 b. a counter electrode, and 
 c. a working electrode; and 
 
 (iii) a reagent composition containing a reagent for detecting an analyte applied directly to the second surface of the working electrode; and 
   contacting the sample of water with the sensor to measure the analyte.   
     
     
         33 . The method according to  claim 32 , wherein there are a plurality of working electrodes, wherein the working electrodes each have a reagent composition applied to the second surface of each working electrode, the reagent composition selected from the group consisting of a composition containing a reagent for detecting free chlorine, a composition containing a reagent for detecting total chlorine, and a reagent composition for detecting water hardness and a reagent composition for detecting total alkalinity. 
     
     
         34 . The method according to  claim 33 , wherein the working electrode comprises two working electrodes, a first working electrode and a second working electrode, wherein the first electrode has a reagent composition containing a reagent for detecting free chlorine applied to the second surface of the first working electrode and the second working electrode has a reagent composition containing a reagent for detecting total chlorine applied to the second surface of the second working electrode. 
     
     
         35 . The method according to  claim 34 , further comprising a third working electrode, and the third working electrode has a reagent composition for detecting water hardness applied to the second surface of the third working electrode. 
     
     
         36 . The method according to  claim 35 , further comprising a fourth working electrode, and the fourth working electrode has a reagent composition for detecting water total alkalinity applied to the second surface of the fourth working electrode.