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Patent US4548906A successfully refreshed from Google Patents.
US4548906A
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Integral multilayer analytical element for the analysis of ammonia or an ammonia forming substrate and a method for the detection thereof using the same
Assignee: Fujifilm Holdings Corp
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Filing: 1984-05-11
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Granted: 1985-10-22
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Expires: 2004-05-11
Abstract
Abstract An integral multilayer analytical element for the analysis of ammonia or an ammonia forming substrate in a liquid sample is disclosed. The element comprises a transparent support on which an indicator layer for ammonia, a liquid blocking layer, a reagent layer incorporated with a reagent which may react with the substrate to form ammonia, and a spreading layer, are integrally superposed in this order. The improvement is that the liquid blocking layer is made of a porous material which is permeable to ammonia but substantially impermeable to liquids.
Inventors
- 👤 Nobuyoshi Sekikawa
- 👤 Harumi Katsuyama
- 👤 Asaji Kondo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:54
CPC Classifications
C; C12; C12Q; C12Q1/00; C12Q1/34; C12Q1/58; G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/52; G01N33/525; G01N33/526; G01N33/62; G01N2333/00; G01N2333/90; G01N2333/914; G01N2333/978; Y; Y10; Y10S; Y10S435/00; Y10S435/805; Y10S435/807; Y10T; Y10T436/00; Y10T436/17; Y10T436/173845; Y10T436/175383
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
176 words
An integral multilayer analytical element for the analysis of ammonia or an ammonia forming substrate in a liquid sample, said element comprising a transparent support including thereon integrally superposed from the support upward (i) an indicator layer for gaseous ammonia, said indicator layer being visible through said transparent support, (ii) a membrane filter as a liquid blocking layer, said membrane filter being composed of a porous material having voids which are permeable to gaseous ammonia but substantially impermeable to liquid under conditions of use thereof, said porous material being a hydrophobic or hydrophobed material in which no substantial capillary action by water occurs, and said membrane filter being 30 to 300 μm in thickness, having a porosity of more than 25% and a mean pore diameter of from 0.01 to 20 μm, (iii) a reagent layer comprising a water soluble binder and a reagent which may react with the substrate to form ammonia and (iv) a spreading layer, the adhesive strength between said membrane filter and said reagent layer being sufficient to provide an integral unit.
Claim 2
Dependent Claim
176 words
An integral multilayer analytical element for the analysis of ammonia or an ammonia forming substrate in a liquid sample, said element comprising a transparent support including thereon integrally superposed from the support upward (i) an indicator layer for gaseous ammonia, said indicator layer being visible through said transparent support, (ii) a membrane filter as a liquid blocking layer, said membrane filter being composed of a porous material having voids which are permeable to gaseous ammonia but substantially impermeable to liquid under conditions of use thereof, said porous material being a hydrophobic or hydrophobed material in which no substantial capillary action by water occurs, and said membrane filter being 30 to 300 μm in thickness, having a porosity of more than 25% and a mean pore diameter of from 0.01 to 20 μm, (iii) a reagent layer comprising a water soluble binder and a reagent which may react with the substrate to form ammonia and (iv) a spreading layer, the adhesive strength between said membrane filter and said reagent layer being sufficient to provide an integral unit.
Claim 3
Dependent Claim
28 words
The analytical element as defined in claim 1 wherein said ammonia forming substrate is urea and said reagent which reacts with said substrate to form ammonia is urease.
Claim 4
Dependent Claim
29 words
The analytical element as defined in claim 1 wherein said ammonia forming substrate is creatinine and said reagent which reacts with said substrate to form ammonia is creatinine deiminase.
Claim 5
Dependent Claim
21 words
The analytical element as defined in claim 1 wherein said reagent layer further includes a stabilizer and a surface active agent.
Claim 6
Dependent Claim
25 words
The analytical element as defined in claim 1 wherein said indicator layer includes a dye precursor which forms a dye in the presence of ammonia.
Claim 7
Independent Claim
242 words
A method for the detection of ammonia or an ammonia forming substrate in a liquid sample, which comprises: providing an integral multilayer analytical element for the analysis of ammonia or the ammonia forming substrate, said element comprising a transparent support including thereon integrally superposed from the support upward (i) an indicator layer for gaseous ammonia, said indicator layer being visible through said transparent support, (ii) a membrane filter as a liquid blocking layer, said membrane filter being composed of a porous material having voids which are permeable to gaseous ammonia but substantially impermeable to liquid under conditions of use thereof, said porous material being a hydrophobic or hydrophobed material in which no substantial capillary action by water occurs, and said membrane filter being 30 to 300 μm in thickness, having a porosity of more than 25% and a pore diameter of from 0.01 to 20 μm, (iii) a reagent layer comprising a water soluble binder and a reagent which may react with the substrate to form ammonia and, (iv) a spreading layer, the adhesive strength between said membrane filter and said reagent layer being sufficient to provide an integral unit, spotting said sample on said spreading layer of said element, and measuring visually or photometrically through the transparent support the development or fading of color in the indicator layer resulting from the reaction between the indicator and ammonia which was formed in the reagent layer and passed through the liquid blocking layer.
Claim 8
Independent Claim
242 words
A method for the detection of ammonia or an ammonia forming substrate in a liquid sample, which comprises: providing an integral multilayer analytical element for the analysis of ammonia or the ammonia forming substrate, said element comprising a transparent support including thereon integrally superposed from the support upward (i) an indicator layer for gaseous ammonia, said indicator layer being visible through said transparent support, (ii) a membrane filter as a liquid blocking layer, said membrane filter being composed of a porous material having voids which are permeable to gaseous ammonia but substantially impermeable to liquid under conditions of use thereof, said porous material being a hydrophobic or hydrophobed material in which no substantial capillary action by water occurs, and said membrane filter being 30 to 300 μm in thickness, having a porosity of more than 25% and a pore diameter of from 0.01 to 20 μm, (iii) a reagent layer comprising a water soluble binder and a reagent which may react with the substrate to form ammonia and, (iv) a spreading layer, the adhesive strength between said membrane filter and said reagent layer being sufficient to provide an integral unit, spotting said sample on said spreading layer of said element, and measuring visually or photometrically through the transparent support the development or fading of color in the indicator layer resulting from the reaction between the indicator and ammonia which was formed in the reagent layer and passed through the liquid blocking layer.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-10-21 | 1989-04-22 | 1989-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-21 | 1993-04-22 | 1993-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-21 | 1997-04-22 | 1997-10-22 | $7700.00 | Window Closed / Lapsed |