ENZYMATIC DETERMINATION OF UREA IN SERUM BASED ON PH MEASUREMENT WITH THE FLOW INJECTION METHOD

A method based on the Flow Injection Analysis system incorporating a flow-through capillary pH-electrode is described and used for the enzymatic determination of urea in aqueous and serum samples. By maintaining a constant buffering capacity of the carrier stream solution, a linear relationship between the recorded pH signal and the urea content is obtained. Attaining the analytical readout within 30 s of sample introduction, the sampling rate was 60 samples per hour and the reproducibility of measurement was. 0029 pH unit corresponding to. 52%. When soluble urease was used in the carrier stream, the consumption was 25 units per analysis. The possibility of further reducing the enzyme consumption by using the merging zone principle in the Flow Injection stop-flow system is discussed. © 1979, American Chemical Society. All rights reserved.