A Colorimetric Method for Determination of Serum Chloride.

HAVE INSTITUTED a colorimetric chloride procedure which has been in use for 3 years in our laboratory and has met with great success. This colorimetric method is based on a procedure used in automated syStems* (2, 3). It is extremely simple, quite accurate, and gives highly reproducible results even in the hands of student technicians. Those laboratories not having access to a chloridometer or automated systems, or even those not wanting to burden their automated systems with more work, may find this method suitable for their needs. Basically, the method consists of the addition of chloride ions to a solution of mercuric thiocyanate and ferric nitrate. The chloride ions upset an equilibrium established between the latter two salts, thereby allowing the formation of a brown ferric thiocyanate complex which is quantitatively proportional to the amount of chloride added.