Electrochemical detection of peroxide-containing compounds

Abstract

A sensing electrode, and an electrochemical system and method utilizing same for detecting peroxide-containing compounds in a sample, are provided. The sensing electrode is a carbon electrode having ions of a metal that promotes decomposition of a peroxide absorbed to its surface, optionally along with a solid electrolyte membrane.

What is claimed is: 
     
         1 . A sensing electrode comprising a carbon electrode and a functional moiety being in association with at least a portion of a surface of said electrode, said functional moiety comprising at least one metal species that promotes decomposition of hydrogen peroxide. 
     
     
         2 . The electrode of  claim 1 , wherein said electrode is a carbon fiber microelectrode. 
     
     
         3 . The electrode of  claim 1 , wherein said carbon electrode is gas-permeable. 
     
     
         4 . The electrode of  claim 1 , wherein said functional moiety comprises metal ions. 
     
     
         5 . The electrode of  claim 4 , wherein said metal ions undergo reduction to thereby provide metal particles, upon application of a potential in a range of from about −0.05 to about 2 volts. 
     
     
         6 . The electrode of  claim 4 , wherein said functional moiety further comprises particles of said metal. 
     
     
         7 . The electrode of  claim 6 , wherein an amount of said particles of said metal is less than 70 mol %, or less than 65 mol %, of the total number of moles of said metal in said functional moiety. 
     
     
         8 . The electrode of  claim 6 , wherein a mol ratio of said metal ions and said particles of said metal ranges from 70:30 to 30:70. 
     
     
         9 . The electrode of  claim 1 , wherein said metal is silver. 
     
     
         10 . The electrode of  claim 1 , wherein said functional moiety comprises at least one metal species having an organic moiety associated therewith. 
     
     
         11 . The electrode of  claim 10 , wherein said at least one metal species having an organic moiety associated therewith is an organic salt of said metal, comprising a metal ion and an organic anion. 
     
     
         12 . The electrode of  claim 11 , wherein said metal is silver and said organic salt of said metal is silver benzoate. 
     
     
         13 . The electrode of  claim 1 , further comprising an ion-permeable material absorbed to said surface. 
     
     
         14 . The electrode of  claim 1 , usable for determining a presence and/or level of a peroxide-containing compound in a sample. 
     
     
         15 . A sensing system comprising a sensing electrode according to  claim 1 , the sensing electrode being connectable to a power source. 
     
     
         16 . The sensing system of  claim 15 , wherein said sensing electrode forms a part of an electrochemical cell. 
     
     
         17 . The system of  claim 16 , wherein said electrochemical cell further comprises an electrolyte, and wherein at least a portion of said sensing electrode contacts said electrolyte. 
     
     
         18 . The system of  claim 17 , wherein said electrolyte features an alkaline pH. 
     
     
         19 . The system of  claim 15 , being devoid of means for deaerating the electrochemical cell prior to contacting the system with a sample. 
     
     
         20 . The system of  claim 15 , further comprising a device for measuring an electrochemical parameter of said sensing electrode. 
     
     
         21 . The system of  claim 15 , being configured such that upon application of a potential, a portion of said metal species is in a form of metal particles, said portion being no more than 70 mol % of the total amount of said metal species. 
     
     
         22 . The system of  claim 15 , wherein said functional moiety comprises metal ions and wherein upon application of a potential, a portion of said metal ions is converted into said metal particles, said portion being no more than 50 mol % of the amount of said metal ions. 
     
     
         23 . The system of  claim 15 , being configured such that upon contacting a sample containing a peroxide-containing compound with said sensing electrode, a presence and/or level of an electrochemical parameter generated in response to applying potential to said sensing electrode is indicative of a presence and/or level of the peroxide-containing compound. 
     
     
         24 . A method of detecting a peroxide-containing compound in a sample, the method comprising:
 contacting the sample with a sensing electrode according to  claim 1 ;   applying a potential to the sensing electrode; and   measuring an electrochemical parameter of said sensing electrode, wherein a presence and/or level of said parameter is indicative of a presence and/or level of the peroxide-containing compound in the sample.   
     
     
         25 . The method of  claim 24 , wherein said electrochemical parameter comprises an electrical current generated at said sensing electrode, wherein a presence and/or level of said electrical current is indicative of a presence and/or level of the peroxide-containing compound. 
     
     
         26 . The method of  claim 24 , being devoid of deaerating the system. 
     
     
         27 . The method of  claim 24 , wherein the sample comprises oxygen. 
     
     
         28 . The method of  claim 24 , further comprising, prior to introducing said sample, repetitively applying said potential for at least 5 consecutive times. 
     
     
         29 . The method of  claim 28 , wherein repetitively applying said potential is performed such that a portion of said metal species is converted to metal particles, said portion being no more than 50 mol % of the total amount of said metal species.