A highly sensitive, simple determination of serum iron using chromazurol B.

A highly sensitive, simple determination of serum iron and binding capacity is described. FeIII/FeII reacts with chromazurol B (CAB) and cetyltrimethyl ammonium bromide (CTMA), the resulting substance being a highly coloured ternary complex. Maximal absorbance of the complex occurs at pH 4.6--5.5 at 630 nm. Lambert Beer's law holds between 0 and 80 mumol Fe/l. Molar absorptivity is 1.68 X 10(5) 1 . mol-1 . cm-1 at 630 nm. Interference by other serum components is negligible even at high concentrations.