Better Sampling Captures Ubiquitous Methylsiloxanes

Environmental researchers in Sweden have developed an improved method to measure trace amounts of cyclic volatile methylsiloxanes (cVMS) in worms, fish, birds, and other animals (Anal. Chem., DOI: 10.1021/ac102406a). These compounds are widely used to make silicone polymers and as solvents for personal care and household products, but they have come under regulatory scrutiny in Canada, the U.K., and the U.S. for being persistent and bioaccumulative in the environment. Studying the presence of cVMS molecules, in particular decamethylcyclopentasiloxane, known as D5 (shown here), in animals is difficult. One problem is the compounds’ ubiquitous nature: They are found in deodorant and in silicone-based lab equipment, which means that sample contamination can occur easily. Another problem is that the molecules are volatile enough to evaporate from prepared samples before measurements can be made. Amelie Kierkegaard, Margaretha Adolfsson-Erici, and Michael S. McLachlan at Stockholm University devised a “purge and trap” method that minimizes handling and environmental exposure of the compounds as they are extracted from animal tissue, trapped in concentrated form, and analyzed by mass spectrometry.