Chloride ion selective membrane and sensor
A chloride selective electrode membrane comprises a polymeric matrix wherein the matrix comprises an epoxy resin, and an amine agent selected from the group consisting of polyamides, amidoamines and mixtures thereof. The amine agent is present in stoichiometric excess and functions as both curing agent and chloride selective agent.
1. A chloride selective electrode membrane comprising a polymeric matrix wherein said matrix comprises:
an epoxy resin curable by an amine agent; and
an amine curing agent selected from the group consisting of polyamides, amidoamines and mixtures thereof, wherein said amine curing agent is present in stoichiometric excess over the amount required for complete curing of the epoxy resin.
2. A chloride selective electrode membrane according to claim 1 , wherein said amine curing agent is a polyamide.
3. A chloride selective electrode membrane according to claim 2 wherein said polyamide is prepared by reacting an acid component and a polyalkylene polyamine component, said acid component comprising an unsaturated fatty acid dimer.
4. A chloride selective electrode membrane according to claim 3 wherein said unsaturated fatty acid dimer comprises a polyunsaturated fatty acid dimer.
5. A chloride selective electrode membrane according to claim 4 further comprising a monounsaturated fatty acid dimer.
6. A chloride selective electrode membrane according to claim 4 wherein said polyunsaturated fatty acid dimer is a C18 polyunsaturated fatty acid dimer.
7. A chloride selective electrode membrane according to claim 5 wherein said monounsaturated fatty acid dimer is oleic acid dimer.
8. A chloride selective electrode membrane according to claim 3 wherein said unsaturated fatty acid dimer is a dimerized fatty acid from an oil selected from tall oil, castor oil, linseed oil, soybean oil and mixtures thereof.
9. A chloride selective electrode membrane according to claim 3 wherein said polyalkylene polyamine component is selected from the group consisting of diethylene triamine, triethylene tetramine and tetraethylene pentamine, and mixtures thereof.
10. A chloride selective electrode membrane according to claim 1 wherein said polymer matrix further comprises an adhesion promoter selected from the group consisting of clays, silicas, silicates and mixtures thereof.
11. A chloride selective electrode membrane according to claim 1 , wherein said epoxy resin is prepared by reacting bisphenol A and epichlorohydrin.
12. A chloride selective electrode membrane according to claim 1 wherein the amount of said amine curing agent is present in a stoichiometric excess of at least 150%.
13. A chloride selective electrode membrane according to claim 1 wherein said amine curing agent is an amidoamine.
14. A chloride selective electrode membrane according to claim 13 wherein said amidoamine is prepared by reacting an acid component and an amine component, said acid component comprising monomeric saturated and unsaturated fatty acids.
15. A chloride selective electrode membrane according to claim 14 wherein said amine component is selected from the group consisting of alkylene diamines and polyalkylene polyamines and mixtures thereof.
16. A method of applying the chloride selective membrane material of claim 1 to an inert substrate, said method comprising:
dispensing said material to onto said substrate; and
heating the substrate containing dispensed chloride selective material to obtain chloride selective membrane.
17. A chloride selective electrode which comprises a chloride selective electrode membrane comprising a polymeric matrix, wherein said matrix comprises:
an epoxy resin curable by an amine agent; and
an amine curing agent selected from the group consisting of polyamides, amidoamines and mixtures thereof wherein said amine curing agent is present in stoichiometric excess over the amount required for complete curing of the epoxy resin.
18. A system for measuring chloride ion in a fluid, said system comprising: a chloride selective electrode according to claim 17 a reference electrode; and means for measuring the electromotive force between said chloride selective electrode and said reference electrode.
19. A chloride selective electrode membrane according to claim 17 wherein
said amine curing agent is present in a stoichiometric excess of at least 150%.
20. A method of applying the chloride selective membrane material of claim 19 to an inert substrate, said method comprising:
dispensing said material to onto said substrate; and
heating the substrate containing dispensed chloride selective material to obtain chloride selective membrane.
21. A sensor assembly for determining chloride ion in a test liquid, comprising:
an electrically insulated substrate having a surface with a reference electrode and
a chloride selective electrode formed thereon, wherein the chloride selective electrode comprises:
a chloride selective electrode membrane comprising a polymeric matrix wherein said matrix comprises:
an epoxy resin curable by an amine agent; and
an amine curing agent selected from the group consisting of polyamide, amidoamines and mixtures thereof, wherein said amine curing agent is present in stoichiometric excess over the amount required for complete curing of the epoxy resin;
means positioned on the surface of the substrate defining a reference flow channel and a sensor flow channel;
said reference flow channel having means for passing reference liquids over the reference electrode; said sensor flow channel having means for passing test liquid over the sensor electrode; and said reference and sensor flow channels defining a common outlet for removing liquids from the assembly.