Complexometric Titration of Calcium and Magnesium by a Semiautomated Procedure

Abstract
A semiautomatic procedure for the direct estimation of both serum calcium and magnesium is described. The indicator used, Eriochrome blue SE (EBSE), has the advantage of stability and freedom from interference by naturally occurring substances. The procedure requires 3-5 min. per sample and is very reproducible. The values obtained agree with those obtained by back-titration of excess chelator and are consistently 0.3 mg./100 ml. less than those obtained by a standard oxalate precipitation method.