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Ionic liquid for homogeneous liquid-liquid microextraction separation/preconcentration and determination of cobalt in saline samples


A novel homogeneous liquid-liquid microextraction technique based on use of ionic liquids (ILs), termed in situ solvent formation microextraction (ISFME) is developed for separation/preconcentration of Co(II) ions. In this method, small amount of sodium hexafluorophosphate (NaPF6, as an ion-pairing agent) was added to the sample solution containing very small amount of 1-hexyl-3-methylimidazolium tetrafluoroborate ([Hmim][BF4], as hydrophilic IL). A cloudy solution was formed as a result of formation of fine droplets of 1-hexyl-3-methylimidazolium hexafluorophosphate [Hmim][PF6]. After centrifuging, the fine droplets of the extractant phase settled to the bottom of the conical-bottom glass centrifuge tube. ISFME is a simple and rapid method for extraction and preconcentration of cobalt ions from water samples that can be applied for the sample solutions containing very high concentrations of salt. Furthermore, this technique is much safer in comparison with the organic solvent extraction. Reliability of the introduced methodology was evaluated by analyzing water reference material. ISFME was successfully applied to determining cobalt(II) in real water samples. Schiff base ligand, 3,3′-(1E,1E′)-(propane-1,2-diylbis(azan-1-yl-1-ylidene)bis(methan-1-yl-1-ylidene)bis(4-bromophenol) (L) was chosen as a complexing agent. Analysis was carried out using atomic absorption spectrometry. Type and amount of IL, pH and the other parameters were optimized. Under the optimum conditions, the limit of detection (LOD) was 0.06 ng/mL and the relative standard deviation (RSD) was 1.8% for 10 ng/mL cobalt.

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  1. Moreira, F.R., Maia, C.B., and Avila, A.K., Spectrochim. Acta B, 2002, vol. 57, p. 2141.

    Article  Google Scholar 

  2. Cadore, S., Goi, R.D., and Baccan, N., J. Braz. Chem. Soc., 2005, vol. 16, p. 957.

    CAS  Article  Google Scholar 

  3. Mashhadizadeh, M.H., Azimi, M.S., Pesteh, M., Sheikhshoaei, I., Ardakani, M.M., and Karimi, M.A., Spectrochim. Acta B, 2008, vol. 63, p. 889.

    Article  Google Scholar 

  4. Anastas, P.T. and Kirchhoff, M.M., Acc. Chem. Res., 2002, vol. 35, p. 686.

    CAS  Article  Google Scholar 

  5. Nazari, S., Microchem. J., 2008, vol. 90, p. 112.

    Google Scholar 

  6. Kende, A., Csizmazi, Z., Rikker, T., Angyal, V., and Torkos, K., Microchem. J., 2006, vol. 84, p. 63.

    CAS  Article  Google Scholar 

  7. Zhao, E., Shan, W., Jian, S., Liu, Y., and Zhou, Z., Microchem. J., 2011, vol. 83, p. 105.

    Article  Google Scholar 

  8. Zeng, C., Wen, X., Tan, Z., Cai, P., and Hou, X., Microchem. J., 2010, vol. 96, p. 238.

    CAS  Article  Google Scholar 

  9. Skrlikova, J., Andruch, V., Balogh, I.S., Kocurova, L., Nagy, L., and Bazel, Y., Microchem. J., 2011, vol. 99, p. 40.

    CAS  Article  Google Scholar 

  10. Shamsipur, M., Ramezani, M., and Miran Beigi, A.A., Indian. J. Chem., 2012, vol. 51, p. 825.

    Google Scholar 

  11. Dalali, N., Javadi, N., and Agrawal, Y.K., Turk. J. Chem., 2008, vol. 32, p. 561.

    CAS  Google Scholar 

  12. Hosseini, M., Dalali, N., Karimi, A., and Dastanra, A., Turk. J. Chem., 2010, vol. 32, p. 805.

    Google Scholar 

  13. Hosseini, M., Dalali, N., Mohammadnejad, S., and Jamali, R., J. Braz. Chem. Soc., 2012, vol. 23, p. 78.

    CAS  Article  Google Scholar 

  14. Hosseini, M., Dalali, N., and Mohammadnejad, S., J. Chin. Chem. Soc., 2012, vol. 59, p. 872.

    CAS  Article  Google Scholar 

  15. Galán-Cano, F., Lucena, R., Cárdenas, S., and Valcárcel, M., J. Chromatogr. A, 2012, vol. 1229, p. 48.

    Article  Google Scholar 

  16. Fathi, S.A.M. and Yaftian, M.R., J. Hazard. Mater., 2009, vol. 164, p. 133.

    CAS  Article  Google Scholar 

  17. Marmion, M.E., Woulfe, S.R., Neumann, W.L., Nosco, D.L., and Deutsch, E., Nucle. Medic. Bio., 1999, vol. 26, p. 755.

    CAS  Article  Google Scholar 

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Correspondence to Nasser Dalali.

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Hosseini, M., Dalali, N. & Moghaddasifar, S. Ionic liquid for homogeneous liquid-liquid microextraction separation/preconcentration and determination of cobalt in saline samples. J Anal Chem 69, 1141–1146 (2014).

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  • homogeneous liquid-liquid microextraction
  • Schiff base
  • ionic liquids
  • cobalt