Determination of decamethylcyclopentasiloxane in river and estuarine sediments in the UK

Robust analytical procedures for the measurement of decamethylcyclopentasiloxane (D5) in river and estuarine sediments and their application in determining environmental concentrations in the UK are presented for the first time in this work. Novel approaches to minimise commonly reported artefacts are utilised, improving the confidence in the concentrations of D5 reported. Accelerated solvent extraction (ASE) and liquid–solid extraction methods are compared. Both methods use on-column injection gas chromatography/mass spectrometry (GC/MS). Measurements of D5 concentrations in sediments sampled from the river Great Ouse and from the Humber estuary (UK) are also reported. ASE was suitable to measure concentrations of D5 in sediments obtained from the river Great Ouse, UK (186–1450 ng g−1, dry weight) and octamethyltetracyclosiloxane (D4, 12–24 ng g−1, dry weight). C12 linear alkybenzene (C12 LAB), which can be used as a chemical marker for sewage effluent related emissions, was also measured in this analysis. Liquid–solid extraction was optimised to provide more confidence in the lower D5 concentrations measured in the Humber estuary, UK (49–256 ng g−1, dry weight). A Limit of quantitation (LOQ) for D5 of 57–110 and 4 ng g−1 dry weight was determined for ASE and liquid–solid extraction, respectively.