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Bioaccumulation of Decamethylcyclopentasiloxane

Bioaccumulation of Decamethylcyclopentasiloxane. Melissa Eubanks Chem 4101 December 9, 2011. The Problem. Silicones are widely used in the personal care and cosmetics industry Persistence in environment

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Bioaccumulation of Decamethylcyclopentasiloxane

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  1. Bioaccumulation of Decamethylcyclopentasiloxane Melissa Eubanks Chem 4101 December 9, 2011

  2. The Problem • Silicones are widely used in the personal care and cosmetics industry • Persistence in environment • Decamethylcyclopentasiloxane (D5) is not toxic to humans but may build up in the marine environment

  3. Importance of Solving the Problem: • Many companies worry about going silicone free • Influence product performance and cost • Regulate the use of silicones in personal care products • Stop possible effects on environment • Hypothesis: • Decamethylcyclopentasiloxane (D5) is being washed from skin and hair and bioaccumulating in aquatic life.

  4. GC/MS 2

  5. Gas Chromatography • Decamethylcyclopentasiloxane • Mass: 370.77g/mol • BP: 210°C • Volatile compound • Requires small samples • Separating complex mixtures • Very high precision • Sensitive to detect volatile organic mixtures of low concentrations

  6. Mass Spectrometry • Quadrupole MS Analyzer • Fast scan rate • Inexpensive • Easily interfaced to • other Ionization • Methods • Electron Ionization 5

  7. Description of Instrument • Gas Chromatography coupled with Mass Spectrometry • Trace GC Ultra • MD800 MS detector • Electron Ionization • Splitless injector with microseal septum • 5µL sample injection • Injector temperature of 220°C • Carrier Gas: Helium

  8. Experimental Design • Preparing Sediment for Analysis as raw extract3: • Top layer undisturbed sediment collected • Extraction by Sedimentation • Centrifugation • Liquid phase separated from solid • Extraction and centrifuge repeated with remaining solid phase • Liquid phases combined • Wash liquid phases • Centrifugation • Liquid phase separated from any remaining large particles

  9. Preparing Fish Samples • Rinse, wrap and seal in bags, freeze at -17°C • Frozen dorsal fillet • Cold solvent extraction • Centrifuge and repeat extraction • 4mL acetone, 2mL n-hexane • Addition on 20mL water and 0.1g sodium chloride • Centrifugation for 10min • Inject sample into GC/MS

  10. Discussion Multimedia Bioaccumulation Factor (mmBAF) • Use of 13C labeled D5 standards • Bioaccumulative in air breathing marine mammals? • Complex bioaccumulation regulations

  11. References 1.)  Reisch, M. Storm Over Silicones. C&EN Northeast News Bureau 2011, 89, pp 10-13. 2.) Skoog, D.; Holler, F.; Crouch, S. Principles of Instrumental Analysis, 6th ed., Thomson Brooks/Cole: Belmont, 2007. 3.)  Kierkegaard, A.; van Egmond, R.; McLachlan, M. S; Cyclic Volatile Methylsiloxane Bioaccumulation in Flounder and Ragworm in the Humber Estuary. Environmental Science and Technology. 2011, 5936-5942. 4.) Kierkegaard, A.; van Egmond, R.; McLachlan, M. S; Determination of Cyclic Volatile Methylsiloxanes in Biota with a Purge and Trap Method. Anal. Chem. 2010, 82, 9573-9578. 5.) Pickering, G.; Oliff, C.; Rutt, K., The Mass Spectrometric Behavior of Dimethylcyclosiloxanes. Organic Mass Spectrometry. 1975, 10, 1035-1045. 6.)http://www.sigmaaldrich.com/catalog/ProductDetail.do?D7=0&N5=SEARCH_CONCAT_PNO|BRAND_KEY&N4=444278|ALDRICH&N25=0&QS=ON&F=SPEC 7.)http://www.spexcertiprep.com/products/product_organic.aspx?part=S-1110 8.) Almond, M. Becerra, R. Bowes, S. Cannady, J. Ogden, S. Young, N and Walsh R. A Mechanistic Study of the Low Pressure Pyrolysis of Linear Siloxanes. Physical Chemistry Chemical Physics. 2008, 11, 6856-6861

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