Determination of copper from tea samples by dispersive liquid-liquid microextraction method

In this study, copper was enriched in dry tea samples by dispersive liquid-liquid microextraction (DLLME) method using 1-(2-pyridylazo)-2-naphthol (PAN) as ligand and determined by flame atomic absorption spectrophotometer (FAAS). A new method has been developed using central composite design (CCD) which combined with response surface methodology (RSM). The optimum experimental conditions (pH, extraction solvent amount, dispersive solvent amount, vortex time and centrifugation time) were determined using the RSM and applicability of the developed DLLME method to the determination of Cu2+ ions in real samples was investigated. For this purpose, the conditions for the formation of complex and extraction yields (pH, extraction solvent amount, dispersive solvent amount, vortex time and centrifugation time) were optimized by using different concentrations of solutions containing synthetic Cu2+ ion. The obtained data showed that the optimized experimental conditions and the developed method could be applied analytically for the determination of Cu2+ ions in different dry tea samples. The validity and accuracy of the developed and optimized method was checked using a certified standard reference material (NIST SRM 1547 peach leaves) and the data obtained were found to be consistent with the certified values. The recovery values obtained by applying the DLLME method developed under the optimized conditions to SRM found as 98%.