Effect of bromide and iodide on chloride methodologies in plasma or serum

The effect of adding known amounts of bromide and iodide to a plasma pool an several methodologies for measuring chloride ion has been studied. Methods evaluated were coulometric, colorimetric, and ion-specific electrode. Three different types of electrodes were evaluated in order to assess any improvements which might have been made in recent years. The older electrode methodology showed an extremely large positive error in apparent chloride ion concentration in presence of very small amounts of bromide and iodide. Also, there was a delayed return to normal response by this electrode after exposure to bromide or iodide. Both of these problems have essentially been eliminated by the newer electrodes which show responses to added bromide or iodide which are similar to the coulometric and colorimetric methods.