Determination of Total Iron in Environmental Samples by Solid Phase Extraction with Dimethyl(E)-2-(2-methoxyphenoxy)-2-butenedioate

A novel solid phase extraction technique for determination of total iron in environmental water samples was developed. The method is based on sorption of Fe(III) ions on octadecyl silica membrane disk modified with a new synthetic ligand dimethyl(E)-2-(2-methoxyphenoxy)-2-butenedioate (I). Iron(III) is quantitatively retained on the disk in the pH range of 3-7 at a flow rate of 1-7 mL min(-1). The Fe(III) eluted with 10 mL of 0.01 M EDTA and than was measured by flame atomic absorption spectrometry (FAAS) at 248.3 nm. The maximum capacity disk modified by 7 mg of ligand was found to be 197 +/- 2 mu g of iron(III). The breakthrough volume was greater than 2000 mL. The iron(III) was completely recovered (> 99%) from water with a preconcentration factor of more than 200. The limit of detection of the proposed method was 1.00 ng mL(-1). The various cationic and anionic interferences had no effect on the recovery of iron(III) from the binary mixtures. The proposed method was successfully applied to determination of total iron from three different water samples.