Ion Pair Dispersive Liquid-Liquid Microextraction for the Determination of Trace Amounts of Copper(II) in Soil, Multivitamin Tablet, Tea and Water Samples Using Flame Atomic Absorption Spectrometry

Ion pair dispersive liquid- liquid microextraction (IP-DLLME) method combined with flame atomic absorption spectrometry was proposed for the determination of trace amounts of copper(II). By using pyrocatechol violet as chelating agent and cetyltrimethyl ammonium bromide as an ion pairing agent, the trace amount of copper(II) was extracted in chloroform. The factors influencing the formation copper-ligand complex and the extraction efficiency such as, sample pH, extraction time, type and volume of extraction solvent and dispersive solvent, ion pair and ligand concentration were optimized. Under optimum experimental conditions, the enhancement factor of 10.0 was obtained from only 5.0 ml of aqueous phase. The linear dynamic range and the detection limit were 6.0 - 100 μg l-1 and 3.7 mg l-1, respectively. The relative standard deviation for ten replicate determinations of 40.0 µg l-1 of Cu2+ was 1.9 %. Developed method was successfully applied for determination of copper in soil, multivitamin tablet, tea and water samples with good spike recoveries.