A polarographic micromethod for the determination of blood chloride.

Because of the inherent sensitivity of the dropping mercury electrode when used for the quantitative analysis of inorganic ions, the present study was undertaken to determine whether sufficient accuracy and simplicity of operation could be attained to justify its employment as a micromethod for the determination of chloride in blood. Since it was desired to work with such samples as can be conveniently obtained from small laboratory animals for serial analyses, a method has been developed for 0.02 and 0.05 ml. samples of whole blood, plasma, and serum. Kolthoff and Miller (1) have shown that the concentration of chloride ion in a solution can be determined by measurement of the diffusion current of the anodic depolarization wave produced at the dropping mercury electrode. Using 0.1 M potassium nitrate as supporting electrolyte, they found that the diffusion current was directly proportional to chloride concentrations between 10s4 and 2 X lo-’ equivalent per liter. The electrode reaction is