Preconcentration and Determination of Cd, Co, Cu, Ni, Pb, and Zn in Water Samples Using Cloud Point Extraction and Ultrasonic Nebulization Coupled With Inductively Coupled Plasma Optical Emission Spectrometry

Abstract

In this work, the ions of Cd2+, Co2+, Cu2+, Ni2+, Pb2+, and Zn2+ in different natural water samples were separated and pre-concentrated using cloud point extraction and determined in combination with an ultrasonic nebulizer and inductively coupled plasma optic emission spectrometry (USN-ICP-OES). The complexing agents of 1,5-di-phenylthiocarbazone (dithizone) and the Triton X-114 surfactant of (1,1,3,3-tetramethylbutyl) phenyl-polyethylene glycol) were used. Phase separation was observed at pH=7 and the surfactant-rich phase was diluted with 2 mL 2 M HNO3. The ligand concentration, surfactant concentration, pH, ionic strength, interferences, and equilibration of the temperature and time parameters were optimized. Under the optimized conditions, the enrichment factor was calculated for Cd2+ as 12.4, Co2+ as 7.5, Cu2+ as 5, Ni2+ as 9.3, Pb2+ as 9.6, and Zn2+ as 9.2. The limit of detection for Cd2+ was 0.009, Co2+ at 0.01, Cu2+ at 0.01, Ni2+ at 0.01, Pb2+ at 0.012, and Zn2+ at 0.02 ng mL(-1). The method was successfully applied to the analysis of natural water samples.