Honeywell G.m.b.h.

Robert B Koch

John D Skogen

John P Cummings

A continuous-flow method and apparatus for the determination of alcohol in a biological fluid such as blood is disclosed. A packed column containing the enzyme alcohol dehydrogenase physically entrapped in a acrylamide gel together with other special ingredients which extend the active life of the enzyme in the test environment is provided. Downstream of the packed column a transparent measurement cell is provided in conjunction with a fluorescence spectrophotometer which is utilized to measure the fluorescence of the effluent which is directly related to the amount of ethyl alcohol in the original sample. The fluorescence measurement is electrically transformed by conventional means into a direct readout of the alcohol content of the sample. This obtains from the fact that alcohol dehydrogenase catalyzes the oxidation of ethyl alcohol in the presence of non-fluorescening NAD to produce acetaldehyde and fluorescing NADH.sub.2. The alcohol dehydrogenase is immobilized and its activity preserved in a manner which allows many tests to be run without any significant loss of enzyme or enzyme activity thereby accomplishing considerable cost reduction in the procedure.

Blood alcohol analyzer

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.

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Starkville, MS, United States of America

Robert B Koch