Neutral carrier based ion-selective electrode for the determination of total calcium in blood serum

A simple potentiometric determination of the total calcium concentration in human blood serum using a liquid membrane electrode is described. The bound calcium is displaced from its complexes through acidification of the serum sample with an acetate buffer to pH 3.5. A novel neutral carrier based Ca super(2+)-selective electrode showing a much higher rejection of H super(+) ions in comparison to previously described carrier membranes as well as classical ion-exchanger membranes permits the Ca super(2+) determination at such a low pH value.