TETRAMETHYLBENZIDINE - SUBSTITUTE FOR BENZIDINE IN HEMOGLOBIN ANALYSIS

Abstract

Plasma Hb is routinely measured by some modification of the benzidine-H2O2 method, particularly at low concentrations. Because benzidine is carcinogenic, and thus impractical for clinical use under current restrictions, the identification of a noncarcinogenic benzidine derivative has become important. 3,3'',5,5''-Tetramethylbenzidine [TMB] fulfilled this criterion. A method was described which used it for Hb determinations in the range of 1-100 mg/dl. Absorption spectra showed this method to be far less influenced by [human] plasma proteins and other substances than the benzidine method, and the sensitivity of TMB was at least 7 times that of benzidine under comparable conditions.