The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 06, 1976
Filed:
Jul. 11, 1974
John P Cummings, Bloomington, MN (US);
Robert B Koch, Starkville, MS (US);
Honeywell Inc., Minneapolis, MN (US);
Abstract
A continuous method and apparatus for the determination of urea in a biological fluid such as blood, for example, is disclosed. In a continuously flowing system, the biological sample is introduced into a buffered carrier solution of low electrical conductance and is caused to flow into a chamber containing an immobilized enzyme which catalyzes a specific reaction which changes the electrical properties of the solution by increasing the dissociated ion concentration therein. This increase in dissociated ion concentration is directly proportional to the original concentration of urea in the biological sample; and any one of the several conventional electrical measurements may be made to determine the increase in such concentration or the rate of increase in such concentration and thereby determine the concentration of urea in the original biological sample. The buffered carrier solution containing the products of the enzyme-catalyzed reaction is reclaimed by circulating it through a deionization, purification stage in which the solution conductivity is substantially returned to the prereaction value. The carrier solution is recirculated and used for processing additional samples. The enzyme, urease, is immobilized in a manner which allows many tests to be run without any significant loss thereof. The savings in enzyme requirements and the savings accomplished by recirculating the buffered carrier solution greatly reduces the cost of analysis.