Development a robust ionic liquid-based dispersive liquid-liquid microextraction against high concentration of salt combined with flame atomic absorption spectrometry using microsample introduction system for preconcentration and determination of cobalt in water and saline samples

A robust ionic liquid-based method for dispersive liquid-liquid microextraction was developed for the determination of cobalt in saline samples. Its robustness was increased by introducing a common ion of the IL into the sample solution. The concentration of cobalt in the settled phase of the ionic liquid was determined by the FAAS using a homemade microsample injection valve. Under the optimized conditions, the calibration graph was linear in the concentration range from 0.4 to 120 μg L −1 with the detection limit of 0.1 μg L −1 . Accuracy was checked against the ISO standard method. The method was successfully applied to the determination of cobalt in water and saline samples.