Dispersive liquid–liquid microextraction of cadmium(II) for preconcentration prior to flame atomic absorption spectrometric detection in water

Abstract

A dispersive liquid–liquid microextraction procedure for cadmium(II) as its 2-(5-bromo-2-pyridylazo)-5-diethylamino-phenol chelate is presented. Carbon tetrachloride and methanol were used as extraction and dispersive solvents, respectively. After phase separation, the preconcentrated-separated cadmium(II) is determined by flame atomic absorption spectrometry with a microinjection technique. The factors which affected the extraction efficiency, i.e. the pH of the sample solution and the volumes of reagent and sample were investigated. The effects of some alkali, alkali earth, and transition metal ions, and of some anions on the recovery of cadmium were also studied. A preconcentration factor of 250 was obtained for a sample volume of 50 mL under optimum conditions. The method was validated by analysis of certified reference materials and applied to some water samples from Turkey.

Keywords:

• preconcentration
• cadmium(II)
• 2-(5-bromo-2-pyridylazo)-5-diethylamino-phenol
• dispersive liquid–liquid microextraction
• flame atomic absorption spectrometry
• natural waters

Acknowledgments

The authors are grateful to the Unit of the Scientific Research Projects of Erciyes University for the financial support. The authors thank TUBITAK (the Scientific and Technical Research Council of Turkey) for providing Perkin-Elmer 3110 flame atomic absorption spectrometer used in this study. Dr M. Soylak thanks King Saud University for Visiting Professor Program.