orthogonal array design optimisation of an in situ ionic liquid dispersive liquid–liquid microextraction for the detection of phenol and endocrine-disrupting phenols in aqueous samples

In this paper, a dispersive liquid–liquid microextraction (dllme) based on the application of in situ ionic liquids (in situ ionic liquid dllme) was developed for preconcentration and determination of trace amount of phenol and endocrine-disrupting phenols in aqueous samples. the experimental parameters of an in situ ionic liquid dllme method were investigated and optimised using an orthogonal array design. several factors affecting extraction efficiency, including percentage concentration of the ionic liquid, the ratio of ionic liquid to the ion exchanger, extraction time as well as centrifugation time, were investigated and optimised. under the optimal conditions, percentage concentration of the ionic liquid of 5%, the ratio of ionic liquid to the ion exchanger of 1–2, the extraction time of 5 min and centrifugation time of 1 min, the method affords satisfactory recoveries in the range of 99–100%. consistent repeatability (rsd ≤ 5%) with satisfactory linearity (0.9993 ≥ r2 ≤ 0.9999) of results illustrated a good performance of the present method. the method was applied to the determination of endocrine-disrupting phenols in real seawater samples. the relative recovery of spiked, natural seawater samples was higher than 97%.