Spectrophotometric study on the reactions of iron(II) with bromopyrogallol red and pyrogallol red in the presence of quaternary ammonium salt

Abstract

Iron(II) in the presence of quaternary ammonium salt reacts with bromopyrogallol red (BPR) and pyrogallol red (PR) to form a ternary complex. The ternary complex Fe(II)-BPR-TDTA is suitable for the determination of trace amounts of iron. The complex has an absorbance maximum at 635 nm with molar absorptivity 5.6 × 10 4 liters mol −1 cm −1, in which the molar ratio of iron(II) to BPR is 1:3. Beer's law is obeyed over the range 0.08–0.5 μg/ml of iron. Masking agents allow most interferences to be suppressed.