Spectrophotometric study on surfactant sensitizing the chromogenic reaction of Fe(II)with o-phenanthroline

The chromogenic reaction of Fe(Ⅱ) with o-phenan throline was studied in the presence of reductant such as ascorbic acid and positive ion surfactant CTMAB,Fe(Ⅱ) was capable of reacting with o-phenanthroline to form a stable,positively charged,orange complex in the pH range 3.0 to 4.0.The complex had a 3∶1molar ratio for o-phenanthroline and Fe(Ⅱ).In the presence of positive ion surfactant CTMAB,the sensitivity of chromogenic reaction was largely improved.At the maximum absorption wavelength of 510nm,the apparent molar absorptivity was 1.0×105L·mol -1·cm -1.Beer′s law was obeyed in the range of 0.2 to 10μg/mL Fe(Ⅱ).Satisfactory result was achieved in applying the method to determination of trace iron in water.