| abstract |
A method and apparatus for determining the concentration of a component in a sample, i.e. the concentration of urea in biological fluids, such as blood serum, wherein the sample, upon being introduced into solution with a reagent, reacts therewith, causing a continuing change in a characteristic of the solution, and wherein the rate of the reaction is indicative of the concentration of the component in the sample. A sensor is provided for monitoring the characteristic of the solution and for generating a first electrical output signal proportional thereto. Differentiator circuit means are provided for producing a second electrical signal proportional to the time derivative of the first signal, the time derivative signal being indicative of the concentration of the component in the sample. |