UV–vis spectrophotometry is known as a simple and sensitive method for routine analysis of iron. 2-(5-bromo-2-pyridylazo)-5-(diethyl amino) phenol (5-Br-PADAP) is one of a powerful pyridylazo-based chelating reagents and can form highly colored and stable complexes with a series of metals. It is favorable to be used as a colorimetric reagent for spectrophotometry determination of metal ions for many years. 5-Br-PADAP can react with Fe(II) ion to form a purple-colored complex which has two absorption peaks at 555 and 742 nm