Application of conventional and modified cloud point extraction for simultaneous enrichment of cadmium, lead and copper in lake water and fish muscles

• The extraction efficiency of metals is improved by modified cloud point extraction (m-CPE) as compared to conventional approach (c–CPE).
• The preconcentration and enhancement factors obtained by m-CPE were 25–56% increased as compared to c-CPE.
• The elimination of surfactant effects via aqueous media, proposed by m-CPE, boosts up the selectivity of method.
• The analytes in aqueous media is well-matched with the conditions of atomic absorption spectrometry.

A new method based on modification of cloud point extraction for simultaneous enrichment of cadmium, lead and copper in water and fish muscle samples was proposed. The extraction efficiency by modified cloud point extraction (m-CPE) was compared with conventional cloud point extraction (c-CPE) method. The procedure for both CPE methods was comprised of formation of metal complexes with a hydrophobic chelating agent, dithizone, followed by entrapment of the chelates in a nonionic surfactant, Triton X-114. For c-CPE, the surfactant rich phase was treated with ethanolic solution of nitric acid and analyzed by flame atomic absorption spectrometer (FAAS). Whereas for m-CPE, aqueous nitric acid was used to back extract the metal ions from the surfactant rich phase and finally determined. The efficiency of the methods was tested by analyzing certified reference material and standard addition to a real sample. All the experimental parameters were optimized. At optimized experimental conditions, preconcentration and enhancement factors were 62.5 and 78.0 to 83.0 respectively for m-CPE, 25.0 and 56.0% higher than that of c-CPE. This improvement might be due to elimination of the effects of surfactant on the signal of analytes by FAAS. The developed method of m-CPE was applied successfully for analysis of the selected heavy metals in water and muscle tissues samples of fish of different lakes in Sindh, Pakistan.

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