Determination of Fe (III) with 1-nitroso-2-naphthol in Micellar Medium by Derivative Spectrophotometry

摘要

A spectrophotometeric and first derivative spectrophotometeric determination of iron(III) is carried out with 1-nitroso-2-naphthol as complexing reagent in aqueous phase using non-ionic surfactant Tween 40.The iron is 'determined in the range 1.7-120 ng mL~(-1) with detection limit (2sigma) of 1.7 ng mL~(-1) The molar absorptivity and Sandell's sensitivity are 1.69 x (10~4 mol~(-1) cm~(-1)) and 7.9 ngcm~(-2) at 446 nm.The optimum pH of the complex is 1.The critical micelle concentration (cmc) of Tween 40 is 5 %.Absorption studies in the first derivative mode is carried out to determine the absorption maximum of the complex for higher sensitivity and to overcome interference due to the presence of certain metal ions.The present method is compared with that of AAS and no significant difference is noted between the two methods at 95 % confidence level.The method has been applied for the determination of Fe(III) in industrial waste water and steel samples.