A new ligandless cloud point extraction method for preconcentration of iron from natural water samples and FAAS detection

Abstract

A simple, efficient and inexpensive ligandless cloud point extraction method was developed for the preconcentration of trace amounts of iron from natural water samples, followed by flame atomic absorption spectrometry detection. The proposed method is based on the extraction of Fe(III) ions at pH 7.0 using the non-ionic surfactant Triton X-114 without the addition of any chelating ligand. The effect of parameters influencing the extraction efficiency such as sample pH, concentration of surfactant, incubation temperature and time, concentration of NaCl and sample volume were investigated and optimized. The effect of potentially interfering ions on the recovery of iron was also examined. Under optimum conditions, the detection limit (3 sigma) was 0.95 mu g L-1 for Fe using a sample volume of 10 mL. A preconcentration factor of 20 was achieved. The accuracy of the method was checked through the analysis of certified reference materials (SLRS-5 river water, SPS-SW2 Batch 127 surface water) and spiked water samples. The percentage recovery values for spiked water samples were between 92% and 101%.