Contriving to selectively separate drugs with a hydrophilic ionic liquid

The potential of a commercially available imidazolium-based ionic liquid (C2C1imC1SO4) to selectively separate two model emerging contaminants, ethynylestradiol and clenbuterol, from aqueous solutions containing non-ionic surfactants (Triton X-100 and Triton X-102) was proved. After a first stage where the binodal curves and tie-lines of the systems were obtained, all the experimental data were suitably correlated with different empirical equations. Then, a 2-step sequential extraction of ethynylestradiol and clenbuterol was investigated by means of a factorial design. In this way, while ethynylestradiol completely partitions to the light layer no matter the operating conditions, clenbuterol extraction can be tuned by a cautious selection of the ionic liquid concentration. Then, while ionic liquid concentrations higher than 70% led to about 4% of clenbuterol extraction in the upper phase, the operation at concentration levels lower than 18% entailed up to 96% of removal. The confirmation of this behavior with synthetic urine proved the relevance of the present data for the implementation of a separation process allowing the selective removal of clenbuterol and ethynylestradiol from aqueous streams, which poses undoubted significant environmental and analytical interest.