Indicator device

• US 6,436,347 B1
• Filed: 05/30/2000
• Issued: 08/20/2002
• Est. Priority Date: 01/21/1999
• Status: Expired due to Term

• Current Assignee: Vital Signs Incorporated (Becton, Dickinson & Co)
• Original Assignee: Mincor AB
• Inventors: Cedeon, Andras
• Primary Examiner(s): Warden, Jill
• Assistant Examiner(s): CROSS, LATOYA I
• Application Number:
  US09/580,438
• Time in Patent Office: 812 Days
• Field of Search: 422/55, 422/57, 422/56, 436/127, 436/133, 128/205.23
• US Class Current: 422/429
• CPC Class Codes: G01N 31/223 for investigating presence of specific gases or aerosols G01N31/221, G01N31/222 take precedence; actuation of fire alarm by presence of smoke or gases G08B17/10
• CPC Class Codes: Y10T 436/20 Oxygen containing
• CPC Class Codes: Y10T 436/204998 Inorganic carbon compounds

Abstract

A fast-response colorimetric carbon dioxide indicator device which is substantially insensitive to humidity and comprises a chemically inert substrate and an indicator composition supported by the substrate and responsive to exposure to carbon dioxide in expired respiratory air to undergo a color changing reaction. The indicator composition includes a pH sensitive dye and a basic substance having the general formula

in which

X is a nitrogen or phosphorus atom,

each of R₁, R₂, R₃ and R₄ is an alkyl,

Y⁻ is an anion selected from the group consisting of hydroxide, fluoride, chloride, bromide, iodide, carbonate, and tetrafluoroborate,

at least one of the alkyls R₁, R₂, R₃ and R₄ having at least 13 carbon atoms and at least one of the other alkyls having from 6 to 8 carbon atoms, the remaining alkyls, if any, having from 1 to 12 carbon atoms.

Claims

1. A fast-response calorimetric carbon dioxide indicator device which is substantially insensitive to humidity and comprises a chemically inert substrate and an indicator composition supported by the substrate and responsive to exposure to carbon dioxide in expired respiratory air to undergo a colour changing reaction, said indicator composition including pH sensitive dye and a basic substance having the general formula

in which

X is nitrogen or phosphorus atom,

each of R₁, R₂, R₃, and R₄ is an alkyl,

Y⁻

is an anion selected from the group consisting of hydroxide, fluoride, chloride, bromide, iodide, carbonate, and tetrafluoroborate,

at least one of the alkyls R₁, R₂, R₃ and R₄ having at least 13 carbon atoms and at least one of the other alkyls having from 6 to 8 carbon atoms, the remaining alkyls, if any, having from 1 to 12 carbon atoms;

the remaining alkyls, if any, is any alkyl in the formula that does not have at least 13 carbon atoms or 6-8 carbon atoms.

2. A fast-response calorimetric carbon dioxide indicator device as claimed in claim 1, in which only one of the alkyls has 14 carbon atoms and each of the other three alkyls has 6 carbon atoms.

3. A fast-response calorimetric carbon dioxide indicator device as claimed in claim 1, in which the indicator composition includes no additional substance affecting the hydrophilic properties of the indicator composition or the permeability thereof to carbon dioxide.

4. A fast-response calorimetric carbon dioxide indicator device as claimed in claim 1, in which the indicator composition is applied as a coating to the substrate.