Detection and Characterization of Poly(dimethylsiloxane)s in Biological Tissues by GC/AED and GC/MS

摘要

We have developed a sensitive method for the detection, characterization, and quantitation of low molecular weight silicones using gas chromatography coupled with atomic mission detection (GC/AED) and gas chromatography/ mass spectrometry (GC/MS). Using this approach, we have detected 12 distinct silicon-containing peaks in PDMS-V poly(dimethylsiloxane) oil by GC/AED, and we have used CC/MS analysis to identify some of the abundant peaks by MS spectral matching. Polydimethylpolysiloxanes contain 37.8% silicon; therefore, the amount of po1y(dimethylsiloxane) in each peak can be calculated from its silicon content. The first three GC peaks from PDMS-V were identified as dodecamethylpentasiloxane, tetradecamethylhexasiloxane, and hexadecamethylheptasiloxane using wiley Mass Spectral Library match (> 90%). Peaks 4-12 could not be matched unequivocally with the spectral library but showed ionic fragments characteristic of PDMS (73, 147, 221,281,295, and 369 amu). The detection limit for silicones using GC/AED and GC/MS systems was found to be 80 and 10 pg/μL, respectively. Studies were conducted using mouse liver homogenates spiked with varying amounts of PDMS-V, and the recovery wa, found to be greater than 90% over a wide range of PDMS-V concentrations. This method appears to work equally well for both linear and cyclic poly(dimethylsiloxane)s. THUS, the methodology described here has the potential to allow the measurement of less than 1 μg of silicone/g of biological tissue. The overall goal of this research is to establish and validate a methodology by which the unequivocal identification and quantitation of poly(dimethylsiloxane)s can be accomplished.