A Simple Flow Injection Spectrophotometric Determination of Iron Using Nitroso-R Salt as Complexing Agent

Abstract

Flow injection (FI) spectrophotometric method for iron (III) determination using Disodium-1-nitroso-2-naphthol-3,6disulphonate (nitroso-R salt) is performed. It is based on the measurement of Fe(III)-nitroso-R salt complex at 720 nm formed by the reaction between Fe(III) and nitroso-R salt in an acetate buffer solution pH 5. The FI parameters that affect the signal response have been optimized in order to get the better sensitivity and low standard deviation. The linear range for determination of iron in water samples was over the range of 0.05- 4.0 μg mL -1 with a correlation coefficient (r 2 ) of 0.9997. The limit of detection (3σ) was 0.011 μg mL −1 with sample throughput of 110 samples h -1 . The repeatability measured from three standard Fe (III) (0.1, 2.0 and 4.0 μg mL −1 ) were 1.42, 1.29 and 1.01% (n = 11) respectively. The proposed method was successfully applied to determination of Fe (III) in water samples and found to be in good agreement with those obtained by flame atomic absorption spectrophotometric (FAAS) method.