This document specifies a method for the quantitative determination of selected cyclic volatile methylsiloxanes (cVMS) in non-filtered water samples by purge and trap extraction with isotope dilution gas chromatography-mass spectrometry (GC-MS).

This method is applicable to the determination of individual cVMS, including:

— octamethylcyclotetrasiloxane (D4);

— decamethylcyclopentasiloxane (D5);

— dodecamethylcyclohexasiloxane (D6);

in surface water, ground water, and wastewater. It can be applied to samples within the concentration range of 0,01 µg/l to 1 µg/l of each of the target compounds. Depending on the matrix, the method may also be applicable to higher concentrations ranging from 1 µg/l to 100 µg/l after suitable dilution of the sample or reduction in sample size.