Supramolecular solvent-based microextraction for the preconcentration of Pb²⁺ and Cd²⁺ prior to spectrophotometric detection

Authors: HUMA ZAFAR, FAHEEM SHAH, RAFAQAT ALI KHAN, ASAD MUHAMMAD KHAN, JAN NISAR, BUSHRA ISMAIL

Abstract: Supramolecular solvent-based dispersive liquid-liquid microextraction technique has been developed as a preconcentration tool for the determination of trace level of Pb²⁺ and Cd²⁺. Dodecanol dispersed in tetrahydrofuran has been utilized as a supramolecular-solvent system for the extraction of analytes prior to their quantitative determination with graphite furnace atomic absorption spectrophotometer. Both Pb²⁺ and Cd²⁺, which were efficiently extracted by supramolecular solvent system, were complexed with dithizone followed by the addition of supramolecular solvent. The experimental variables that could possibly influence the extraction efficiency, i.e. pH value, temperature, sample volume, centrifugation time, rate of centrifugation, ionic strength, etc. were subjected to the optimization step. An interference study was also conducted to check the selectivity of developed method. Limit of detection calculated for Pb²⁺ and Cd²⁺ was 0.015 and 0.061 mg L^-1, respectively. The limit of quantification was 0.05 and 0.2 mg L^-1 for Pb²⁺ and Cd²⁺, respectively. The analytical signal was enhanced to 30 times in case of Pb²⁺ and 27 times in case of Cd²⁺. The results obtained revealed that the developed method is rapid, simple, sensitive, and efficient for the determination of both analytes in real water samples.

Keywords: Supramolecular-solvent, lead, cadmium, microextraction, water

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