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A dry reagent delivery system with membrane having porosity gradient

  • US 4,774,192 A
  • Filed: 01/28/1987
  • Issued: 09/27/1988
  • Est. Priority Date: 01/28/1987
  • Status: Expired due to Term
First Claim
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1. A method for the preparation of a dry chemistry reagent system for analysis of heterogenous fluid samples, said method comprising:

  • (a) providing a porous membrane having an essentially uniform composition, said porous membrane being characterized as having two planar surfaces and a porosity gradient from one planar surface to the other, the inherent porosity on at least one of said planar surfaces being essentially exclusive of particulate matter on the order of magnitude of cells present in biological fluid samples;

    (b) sequentially imbibing into said porous membrane (i) an indicator and (ii) a reagent cocktail specific for reaction with an analyte believed to be present in the fluid sample; and

    (c) contacting said porous membrane with an absorption effective amount of conditioning agent, said conditioning agent enhancing the absorption characteristics of the porous membrane to fluid samples, said contact of said porous membrane with a conditioning agent occurring either independent of and prior to time to contact of said porous membrane with an indicator or subsequent to contact of said porous membrane with said indicator.

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