Atmospheric carbon dioxide-induced coacervation in long-chain primary amine micellar solution: Automated microextraction of phthalates based on flow system.

This work reports, for the first time, atmospheric carbon dioxide-induced coacervation in a long-chain primary amine micellar solution for supramolecular solvent formation. Based on this phenomenon, a simple automated microextraction procedure has been developed for the preconcentration and determination of phthalates by high-performance liquid chromatography with ultraviolet detection in drinking water samples and extracts obtained from plastic and silicone kitchenware, as well as baby plastic tableware. The microextraction approach proposed enables rapid and efficient preconcentration of phthalates from samples while eliminating the use of additional coacervation agents. The procedure is based on spontaneous phase separation occurring directly within the mixing chamber of flow system without the need for centrifugation. The formation of supramolecular solvent was confirmed by dynamic light scattering. The composition of the solvent was also established. Under optimal conditions, the technique provides limits of detection (based on a blank test using 3σ) of 6 μg L-1 for dimethyl phthalate, 3 μg L-1 for diethyl phthalate and di-n-octyl phthalate, 2 μg L-1 for di-n-butyl phthalate. The technique developed has been successfully applied to controlling drinking water quality and assessment of the safety of plastic/silicone containers used for storing food products.