Factors affecting the determination of iron species in the presence of ferric iron

The high concentration Fe 3+ in sample had interference on the determination of iron species by spectrophotometric method in which 1,10-phenanthroline was used to as a chromogenic agent. The F − could mask absolutely the effect of Fe 3+ when F − /Fe 3+ molar concentration ratio was 13.3. The temperature or light did not affect the masking action of F − . Low temperature and dark conditions favored the stability of chromophoric complex. This method is suitable for the measure of iron species where the concentration of Fe 3+ is far more than that of Fe 2+ in samples.