This document specifies a method for the determination of certain cyclic volatile methylsiloxanes (cVMS) in environmental water samples with low density polyethylene (LDPE) as a preservative and subsequent liquid-liquid extraction with hexane containing ¹³C-labeled cVMS as internal standards. The extract is then analysed by gas chromatography-mass spectrometry (GC-MS).

NOTE Using the ¹³C-labeled, chemically identical substances as internal standards with the same properties as the corresponding analytes, minimizes possible substance-specific discrimination in calibrations. Since these substances are least soluble in water, they are introduced via the extraction solvent hexane into the system.