Melissa Eubanks Chem 4101 December 9, 2011

 Silicones are widely used in the personal care and cosmetics industry  Persistence in environment  Decamethylcyclopentasiloxane (D 5 ) is not toxic to humans but may build up in the marine environment

 Hypothesis:  Decamethylcyclopentasiloxane (D 5 ) is being washed from skin and hair and bioaccumulating in aquatic life.  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

AdvantagesDisadvantages CE High separation Small sample sizes Fast separations Easily coupled to MS Low concentration difficult Reproducibility problems HPLC Speed High resolution Sensitivity Reproducibility Cost Complexity Low sensitivity for some compounds GC Requires small samples Good at separating complex mixtures Results are rapidly obtained Very high precision Sensitivity to detect volatile mixtures of low concentrations Vapor pressures exceeding 10 –10 torr can be analyzed Certain isomeric compounds cannot be distinguished MS Small sample size Large mass Identify isotopes Destroy samples High Cost Interference Fluorescence High Sensitivity Compounds may need to be derivatized

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 Decamethylcyclopentasiloxane ◦ Mass: g/mol ◦ BP: 210°C ◦ Volatile compound  Requires small samples  Separating complex mixtures  Very high precision  Sensitive to detect volatile organic mixtures of low concentrations

 Quadrupole MS Analyzer  Fast scan rate  Inexpensive  Easily interfaced to other Ionization Methods  Electron Ionization 5

 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

 Preparing Sediment for Analysis as raw extract 3 :  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

 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

Multimedia Bioaccumulation Factor (mmBAF)  Use of 13 C labeled D 5 standards  Bioaccumulative in air breathing marine mammals?  Complex bioaccumulation regulations

1.) Reisch, M. Storm Over Silicones. C&EN Northeast News Bureau 2011, 89, pp ) Skoog, D.; Holler, F.; Crouch, S. Principles of Instrumental Analysis, 6 th ed., Thomson Brooks/Cole: Belmont, ) 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, ) 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, ) Pickering, G.; Oliff, C.; Rutt, K., The Mass Spectrometric Behavior of Dimethylcyclosiloxanes. Organic Mass Spectrometry. 1975, 10, ) RCH_CONCAT_PNO|BRAND_KEY&N4=444278|ALDRICH&N25=0&QS=ON &F=SPEC 7.) ) 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,