A novel cloud point extraction method for separation and preconcentration of cadmium and copper from natural waters and their determination by flame atomic absorption spectrometry

Abstract

A sensitive and simple cloud point extraction method was developed for simultaneous separation and preconcentration of cadmium and copper prior to their determination by flame atomic absorption spectrometry. 4-phenyl-3-thiosemicarbazide was used as complexing agent and the cadmium and copper complexes were extracted from the aqueous phase by Triton X-114 surfactant. The effects of parameters such as sample pH, ligand amount, concentration of surfactant, incubation temperature and time were optimized. For 20 mL of preconcentrated solution, the detection limits (3 sigma) were 0.20 and 0.49 mu g L-1, and the enrichment factors were 20.7 and 19.9 for Cd(II) and Cu(II), respectively. In order to verify the accuracy of the developed method, certified reference materials (SLRS-5 river water and SPS-SW2 Batch 127 surface water) were analysed. Results obtained were in good agreement with the certified values. The proposed method was applied to tap water, river water and seawater samples with satisfactory results.