Ligandless-dispersive liquid-liquid microextraction of trace amount of copper ions.

In the present work, a new ligandless-dispersive liquid-liquid microextraction (LL-DLLME) method has been developed for preconcentration trace amounts of copper as a prior step to its determination by flame atomic absorption spectrometry. In the proposed approach 1,2-dicholorobenzene and ethanol were used as extraction and dispersive solvents, respectively. Some factors influencing on the extraction efficiency of copper and its subsequent determination were studied and optimized, such as the extraction and dispersive solvent type and volume, pH of sample solution, extraction time and salting out effect. Under the optimal conditions, the calibration curve was linear in the range of 1.0 ng mL(-1)-0.6 microg mL(-1) of copper with R(2)=0.9985. Detection limit was 0.5 ng mL(-1) in original solution (3S(b)/m) and the relative standard deviation for seven replicate determination of 0.2 microg mL(-1) copper was +/-1.4%. The proposed method has been applied for determination of copper in standard and water samples with satisfactory results.