In-situ ionic liquid-dispersive liquid-liquid microextraction method to determine endocrine disrupting phenols in seawaters and industrial effluents

We have evaluated an in-situ ionic liquid-dispersive liquid-liquid microextraction procedure for the determination of six endocrine disrupting phenols in seawaters and industrial effluents using HPLC. The optimized method requires 38 mu L of the water-soluble ionic liquid 1-butyl-3-methylimidazolium chloride, and 5 mL of seawater or industrial effluent. After appropriate work-up, a drop (similar to 10 mu L) of an ionic liquid is formed that contains the analytes of interest. It is diluted with acetonitrile and injected into the HPLC system. This procedure is accomplished without heating or cooling the solutions. The method is characterized by (a) average relative recoveries of 90.2%, (b) enrichment factors ranging from 140 to 989, and (c) precisions (expressed as relative standard deviations) of less than 11% when using a spiking level of 10 ng mL(-1). The limits of detection range from 0.8 ng mL(-1) for 4-cumylphenol to 4.8 ng mL(-1) for bisphenol-A.