Determination of endocrine disruptors in bottom sediments using gas chromatography-mass spectrometry with analyte preconcentration by liquid-liquid and magnetic dispersive solid-phase extraction

A method is proposed for extracting and concentrating six common endocrine disruptors (dimethyl-, diethyl-, dibutyl phthalates, bisphenol A, octyl- and nonylphenols) from river bottom sediments. The analytes were extracted using a two-stage concentration approach. In the first stage, analytes were extracted from aqueous solution using an ionic liquid – 1-hexyl-3-methylimidazolium hexafluorophosphate – in the presence of a surfactant (sodium dodecylsulfonate). The volumes used were 200 μL of extractant and 0.5 mL of 12 % surfactant solution, with a 2-minute extraction time. In the second stage, magnetic dispersed solid-phase extraction was performed using magnetically active plant-based carbon modified with reverse-phase reagents – n-octyltrimethoxysilane and n-octadecyltrimethoxysilane. The analyte recovery was 91–99 % for liquid-liquid extraction and 89–99 % for magnetic dispersed extraction. Two-stage concentration combined with gas chromatography-mass spectrometry allowed detection of endocrine disruptors in bottom sediments at levels of 0.4–0.7 µg/kg.