Microwave-assisted extraction followed by gas chromatography-mass spectrometry for the determination of endocrine disrupting chemicals in river sediments

In this study, microwave assisted extraction (MAE) followed by gas chromatography (GC)-mass spectrometry (MS) analysis has been successfully developed for the simultaneous extraction and determination of contrasting endocrine disrupting chemicals (EDCs) including 17N2-estradiol, estrone, 17a-ethynylestradiol, 16a-hydroxyestrone, 4-nonylphenol, 4-tert-octylphenol and bisphenol A in river sediments. For MAE, the effects of various parameters on the extraction efficiency were investigated. It is shown that the most efficient extraction (recovery >74%) of the target compounds was achieved by using methanol as the solvent, an extraction temperature of 110B:C and 15 min of holding time. The cleanup of extracts was carried out by passage through a non-deactivated silica gel column, and a satisfactory elution efficiency of all compounds was achieved using a solvent mixture of ethyl acetate - hexane (4:6, v/v). The spiking experiments show that the mean recovery of the target compounds exceeded 61% at a spiking level of 5 ng/g, and 73% at 10, 40 and 100 ng/g with a good reproducibility. The method developed was applied to the determination of target EDCs in river sediments collected from rivers Uck and Ouse, UK, and results revealed the presence of the chosen compounds at low ng/g level.