Linear and cyclic methylsiloxanes in air by concurrent solvent recondensation–large volume injection–gas chromatography–mass spectrometry

•A simple method for the analysis of volatile methylsiloxane in air is proposed.•The method is based on active sampling combined with CSR–LVI–GC–MS.•The method provided good precision (RSD<9%) and low LOQs (0.03–0.45 ng m−3).•Methylsiloxane concentrations in indoor air ranged from 3.9 to 292668 ng m−3.•Levels of methylsiloxanes in urban air were found from 2.2 to 439 ng m−3.

In the present work, a simple and fast method for the analysis of linear and cyclic methylsiloxanes in ambient air based on active sampling combined with gas chromatography – mass spectrometry (GC–MS) was developed. The retention efficiency of five sampling sorbents (activated coconut charcoal, Carbopack B, Cromosorb 102, Cromosorb 106 and Isolute ENV+) was evaluated and Isolute ENV+ was found to be the most effective. A volume of 2700 L of air can be sampled without significant losses of the most volatile methylsiloxanes. To improve the sensitivity of the GC–MS method, concurrent solvent recondensation – large volume injection (CSR–LVI), using volumes up to 30 µl of sample extract, is proposed and limits of quantification down to 0.03–0.45 ng m−3, good linearity (r>0.999) and precision (RSD %<9%) were obtained. The developed method was applied to the analysis of ambient air. Concentrations of linear and cyclic methylsiloxanes in indoor air ranging from 3.9 to 319 ng m−3 and between 48 and 292668 ng m−3, were obtained, respectively, while levels from 6 to 22 ng m−3 for linear and between 2.2 and 439 ng m−3 for cyclic methylsiloxanes in outdoor air from Barcelona (Spain), were found.