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 formed from an electrode material and 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 or dispersed throughout the electrode material of the working electrode.

What is claimed is: 
     
         1 . A electrochemical sensor for the detection and analysis of an analyte in a solution, the electrochemical sensor comprising:
 (i) an electrically non-conductive support;   (ii) a plurality of electrodes on the support, each electrode comprising an electrode material and having a first surface and an opposite second surface, the 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, such that the reagent composition essentially completely covers the second surface of the working electrode or dispersed throughout the electrode material of the working electrode;   wherein the reagent comprises an indicator for the analyte.   
     
     
         2 . The electrochemical sensor according to  claim 1 , comprising one to eight working electrodes. 
     
     
         3 . The electrochemical sensor according to  claim 1 , wherein the reagent composition completely covers the entire second surface of the working electrode. 
     
     
         4 . The electrochemical sensor according to  claim 1 , wherein the indicator is for copper. 
     
     
         5 . The electrochemical sensor according to  claim 4 , wherein the indicator for copper comprises a buffer. 
     
     
         6 . The electrochemical sensor according to  claim 5 , wherein buffer comprises a phthalate buffer, a phosphate buffer, a citrate buffer, or an acetate buffer. 
     
     
         7 . The electrochemical sensor according to  claim 1 , wherein the reagent composition applied to, or dispersed throughout, the working electrode comprises a reagent for analyzing water hardness. 
     
     
         8 . The electrochemical sensor according to  claim 7 , wherein the reagent composition comprises an indicator for calcium, a cation exchange resin, and a polyelectrolyte polymer. 
     
     
         9 . The electrochemical sensor according to  claim 8 , wherein the indicator for calcium is a copper salt. 
     
     
         10 . The electrochemical sensor according to  claim 9 , wherein the copper salt is selected from the group consisting of copper sulfate, copper chloride and copper nitrate. 
     
     
         11 . The electrochemical sensor according to  claim 9 , wherein the copper salt is copper sulfate. 
     
     
         12 . The electrochemical sensor according to  claim 11 , wherein the copper sulfate is copper sulfate heptahydrate. 
     
     
         13 . The electrochemical sensor according to  claim 1 , wherein the reagent comprises a transition metal salt is selected from the group consisting of transition metal sulfates, transition metal nitrates and transition metal chlorides. 
     
     
         14 . The electrochemical sensor according to  claim 13 , wherein the reagent composition further comprises a polyelectrolyte polymer. 
     
     
         15 . The electrochemical sensor according to  claim 14 , wherein the polyelectrolyte polymer comprises sodium alginate, polyethylene glycol, polyvinyl alcohol, or polyvinylpyrrolidone. 
     
     
         16 . The electrochemical sensor according to  claim 13 , wherein the transition metal of the transition metal salt is copper. 
     
     
         17 . 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. 
     
     
         18 . 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. 
     
     
         19 . 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, or dispersed throughout the electrode material of each working electrode, the reagent composition is 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 reagent composition for detecting water hardness, a reagent composition for detecting total alkalinity, a reagent composition for detecting cyanuric acid, and a reagent composition for detecting copper. 
     
     
         20 . A method of analyzing water, the 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 comprising an electrode material and having a first surface and an opposite second surface, the 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, or dispersed throughout the electrode material of the working electrode; and 
   contacting the sample of water with the sensor to measure the analyte.   
     
     
         21 . The method according to  claim 20 , 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, or dispersed throughout the electrode material of each working electrode, the reagent composition is 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 reagent composition for detecting water hardness, a reagent composition for detecting total alkalinity, a reagent composition for detecting cyanuric acid, and a reagent composition for detecting copper.