SPECTROPHOTOMETRIC DETERMINATION OF FE(III) WITH TIRON IN THE PRESENCE OF CATIONIC SURFACTANT AND ITS APPLICATION FOR THE DETERMINATION OF IRON IN AL-ALLOYS AND CU-BASED ALLOYS

A sensitive spectrophotometric method for the determination of iron wi th tiron and a cationic surfactant, cetylpyridinium chloride, at pH 5. 6 is reported. The complex is extracted into a chloroform-propan-2-ol (4:1) mixture and shows maximum absorbance at 520 nm. Beer's law is ob eyed in the range 1-14 mu g/ml with an average molar absorptivity of 1 58001 mol(-1) cm(-1). The molar ratio as determined by Job's method fo r Fe:tiron:CPC is 1:4:3. Interferences by various ions are examined. Z r,Ti and Mo interfere heavily. The method is applied for the determina tion of iron in Al-based and Cu-based alloys, using appropriate maskin g agents.