Quantitative analysis of trace- and ultratrace-level Dimethylsilanediol (DMSD) in water, soil, sediment and biosolids by liquid chromatography-triple quadrupole tandem mass spectrometry

Dimethylsilanediol (DMSD) is a highly water-soluble degradation product of dimethylsiloxane oligomer and polymer materials that may be found in the environment. In this project, we have developed a water analysis method for DMSD based on liquid chromatography-triple quadrupole tandem mass spectrometry (LC/QQQ MS/MS) using C-13-DMSD as an internal standard with and without solid phase extraction (SPE). This included the modification of SPE extraction method for water samples with colloidal particles that may plug the SPE cartridge, the use of a water-based solvent mixture for DMSD elution to promote better ionisation in instrumental analysis and optimisation of instrumental operation conditions for higher sensitivity in QQQ MS/MS analysis. The water method was successfully applied for analysis of DMSD in soil, sediment and biosolids by coupling the water extraction of DMSD from solid samples with the pre-column SPE extraction of the water extracts. The method detection limit (MDL) for direct water analysis was found to be as low as 2 mu g L-1, while the current MDLs for sediment, soil and biosolids are in the range of 10 to 100 ng g(-1) dw. The matrix spike recovery varied from 79% to 99% for all samples, confirming its general validity of the method. Compared with the published methods, this method requires less sample processing and has lower MDLs for DMSD analysis in environmental samples.