Interference studies were performed by spiking some cations,
Ca2+, Mg2+, Co2+, Ni
2+, Cr3+, Cu2+ and Mn2+ into Fe(III) 10 ppm
solutions at the final concentration of 1, 5 and 10 ppm (10:1, 2:1
and 1:1 concentration ratios of Fe(III):interference ion). Peak
heights obtained from these solutions were compared with
standard Fe(III), 10 ppm. It was found that the system could
tolerate these cations at least up to 1:1 concentration ratio
(10 ppm Fe:10 ppm interference ion). Higher interference
ratios were not studied because pharmaceutical preparations
normally do not contain these minerals at higher amounts.