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US4961834A Expired / Lapsed US ⏱️ 0.0 years remaining

Electrochemical measuring cell for amperometrically determining ammonia and derivatives thereof

Assignee: Draegerwerk AG and Co KGaA
•
Filing: 1989-12-11
•
Granted: 1990-10-09
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Expires: 2009-12-11
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Abstract

Abstract The invention is directed to an electrochemical measuring cell for determining ammonia and its derivatives in a gaseous or liquid measuring sample. The measuring cell has at least one anode and at least one cathode which are disposed in an electrolyte chamber filled with a soluble electrolyte. The electrolyte chamber is closed off in the direction facing toward the measuring sample by a permeable membrane. The measuring cell provides a more selective ammonia sensor having the following advantages: a short response time, a linear response and exhibits the lowest possible tendency toward drift. The electrolyte of the measuring cell is so configured that the reaction products of the measuring reaction do not affect subsequent measurements. For this purpose the measuring cell, which operates in an amperometric measuring mode, contains a soluble non-oxidizable reagent in the electrolyte which reacts completely with ammonia to form an oxidizable product which is convertible by its oxidation into non-oxidizable soluble secondary products which are chemically and electrochemically inert.

Inventors

  • 👤 Uwe Kuhn
  • 👤 Christiane Roocks
  • 👤 Herbert Kiesele

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-03 18:38
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/404; G01N27/4045; G01N33/00; G01N33/0004; G01N33/0009; G01N33/0027; G01N33/0036; G01N33/0054; Y; Y02; Y02A; Y02A50/00; Y02A50/20

Claims Analysis

Total Claims: 11
Claim 1
Independent Claim 101 words
An electrochemical measuring cell for determining the content of ammonia and the derivatives thereof in a fluid measuring sample, the measuring cell comprising: a housing having an opening directed toward the sample to be measured and defining an electrolyte chamber; a permeable membrane mounted on said housing for closing off said chamber; an anode and a cathode disposed in said chamber so as to be in spaced relationship to each other; and, a non-oxidizable soluble reagent contained in said electrolyte for completely reacting with ammonia while forming an oxidizable product which oxidizes into non-oxidizable, soluble, chemically and electrochemically inert secondary products.
Claim 2
Dependent Claim 101 words
An electrochemical measuring cell for determining the content of ammonia and the derivatives thereof in a fluid measuring sample, the measuring cell comprising: a housing having an opening directed toward the sample to be measured and defining an electrolyte chamber; a permeable membrane mounted on said housing for closing off said chamber; an anode and a cathode disposed in said chamber so as to be in spaced relationship to each other; and, a non-oxidizable soluble reagent contained in said electrolyte for completely reacting with ammonia while forming an oxidizable product which oxidizes into non-oxidizable, soluble, chemically and electrochemically inert secondary products.
Claim 3
Dependent Claim 22 words
The electrochemical measuring cell of claim 1, said reagent being an organic ammonium salt which reacts with ammonia to form an amine.
Claim 4
Dependent Claim 15 words
The electrochemical measuring cell of claim 1, said electrolyte containing a zwitterionic buffer (Good buffer).
Claim 5
Dependent Claim 12 words
The electrochemical measuring cell of claim 1, said reagent being trishydroxymethylaminomethanehydrochloride (TRIS-hydrochloride).
Claim 6
Dependent Claim 13 words
The electrochemical measuring cell of claim 1, said electrolyte including a hygroscopic additive.
Claim 7
Dependent Claim 22 words
The electrochemical measuring cell of claim 5, said hygroscopic additive being an additive selected from the group consisting of tetramethylammoniumchloride and lithiumchloride.
Claim 8
Dependent Claim 25 words
The electrochemical measuring cell of claim 1, said measuring electrode comprising amorphous gold containing rhodium and sintered with PTFE powder as a hydrophobic binding agent.
Claim 9
Dependent Claim 25 words
The electrochemical measuring cell of claim 1, said measuring electrode comprising amorphous gold containing rhodium and sintered with polypropylene powder as a hydrophobic binding agent.
Claim 10
Dependent Claim 28 words
The electrochemical measuring cell of claim 1, said reference electrode and said counter electrode being made of sintered iridium finely distributed in PTFE as a hydrophobic binding agent.
Claim 11
Dependent Claim 28 words
The electrochemical measuring cell of claim 1, said reference electrode and said counter electrode being made of sintered iridium finely distributed in polypropylene as a hydrophobic binding agent.

References Cited (Backward Citations)

US3649505A Cited
US3830718A Cited
US3869354A Cited
US4297173A Cited
US4842697A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1993-10-08 1994-04-09 1994-10-09 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1997-10-08 1998-04-09 1998-10-09 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2001-10-08 2002-04-09 2002-10-09 $7700.00 Window Closed / Lapsed

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