Analysis of linear and cyclic methylsiloxanes in water by headspace-solid phase microextraction and gas chromatography–mass spectrometry

This paper proposes a new method for the analysis of linear and cyclic methylsiloxanes in water samples based on headspace-solid phase microextraction (HS-SPME) coupled to gas chromatography–mass spectrometry (GC–MS). The extraction efficiency of four commercially available SPME-fibres was evaluated and it was found that a 65 μm polydimethylsiloxane/divinylbenzene (PDMS/DVB) coating was the most suitable for the extraction of siloxanes. The method provided good linearity (r > 0.999) and precision (RSD % <17%), and low limits of quantification ranging from 0.01 to 0.74 ng L−1 for linear siloxanes and between 18 and 34 ng L−1 for cyclic siloxanes. The HS-SPME-GC–MS method was applied to the analysis of linear and cyclic siloxanes in river waters from Catalonia (NE, Spain) and the results showed concentrations of linear and cyclic siloxanes ranging from 0.09 to 3.94 ng L−1 and 22.2 to 58.5 ng L−1, respectively.