A modified spectrophotometric method for the determination of trace amounts of phenol in water

Abstract

A modified spectrophotometric method has been developed for the determination of phenol in water. The method is based on the reaction between phenol, sodium nitroprusside and hydroxylamine hydrochloride in a buffer medium of pH 10.6–11.8. The linear dynamic range is 0.05–5.0 mg l−1. The optimum determination wavelength is at 700 nm. The molar absorptivity is 1.23×104 mol l−1 cm−1. The relative standard deviation of the standard solution of phenol is 1.3% (n=10, C=0.5 mg l−1). The average recovery of water samples spiked with phenol of 2.0 mg l−1 is 98.8% (n=10). The relative error of standard sample (C=0.394±0.003 mg l−1) is 2.0%. F values of the statistical analysis show that there is no significant difference between the proposed method and the 4-aminoantipyrine method. The crystal of the product of the colored reaction was synthesized. According to its IR spectrum, Raman spectrum, Mössbauer spectrum and elemental analysis, the composition and structure of the product have been deduced and the mechanism of the colored reaction has also been investigated.