DETERMINATION OF CADMIUM AND ZINC IN WATER SAMPLES BY FLAME ATOMIC ABSORPTION SPECTROMETRY AFTER CLOUD POINT EXTRACTION

摘要

The phase-separation phenomenon of non-ionic surfactants occurring in aqueous solution was used for the extraction of Cd and Zn from water samples After complexation with 6-(4-mtrophenyl)-2,4-diphenyl-3,5-diaza-bicyc-lo[3,1,0]hex-2-ene (NDDBH) in hydrochloric acid medium (pH 1), the analytes were quantitatively extracted after centrifugation, into the phase rich in the non-ionic surfactant octylphenoxypolyethoxyethanol (Tnton X-114). let-rahydrofuran acidified with 0.1 M HC1 was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry. The adopted concentrations for NDDBH, Triton X-l 14 and hydrochloric acid were all optimized. Detection limits (3 omega) of 0.33 and 0 85 ng/mL along with enrichment factors of157 and 118 for Cd and Zn, respectively, were achieved. The proposed method was applied to the determination of Cd and Zn in acidic solutions of certified reference materials. Comparison with certified values was performed for accuracy evaluation, resulting in good agreement according to the r-test at a 95% confidence level. The high efficiency of cloud point extraction to carry out the determination of the studied analytes in complex matrices was, therefore, demonstrated.