Electrometric method for the determination of chloride in serum and other biologic fluids.

N THE SEARCH for an accurate, rapid, versatile micromethod for chloride determination attention was focused on the simple but interesting dissimilar electrodes of Clark (1). Cunningham and coworkers (2) adapted these electrodes to measure 0-1 sMol of chloride with an error of less than 1 per cent. The chloride in a solution of sulfuric acid was titrated with standardized silver nitrate. The end point was detected with a sensitive galvanometer which measured the current produced by the dissimilar electrodes when the first excess of silver appeared. Unfortunately, the time for equilibration after addition of each increment of silver nitrate was 30 seconds, which prolonged the time for an entire analysis. This problem has been overcome by using a special titrating table which makes equilibrium possible in 2 to 3 seconds after each addition of silver. A special electrical circuit and a Scholander (4) microburet enhance both accuracy and speed (5).