BUN is determined electrochemically by coupling the urease reaction to what measurement?

To correctly determine Blood Urea Nitrogen (BUN) levels electrochemically, BUN measurement is often conducted by coupling the urease reaction, which hydrolyzes urea into ammonia and carbon dioxide. The process involves measuring the conductivity of the solution, as the release of ammonia will change the conductivity over time.

When urea is converted to ammonia, this results in the generation of ions that affect the conductivity of the solution. Thus, monitoring the rate of increase in conductivity over a specific period allows for the quantification of the ammonia produced, which is directly related to the amount of urea (and hence BUN) in the sample.

Other options, such as measuring potential with a urea-selective electrode, are associated with ion-selective electrodes rather than conductivity measurements. The oxidation of ammonia refers to a different reaction pathway and does not specifically relate to the typical electrochemical BUN assay. While carbon dioxide is a product of the urease reaction, it does not provide a direct electrochemical measurement for BUN. Conductivity changes due to the formation of ammonia provide the most relevant and straightforward assessment in this context.