Determination of poly(dimethyl)siloxane–water partition coefficients for selected hydrophobic organic chemicals using ¹⁴C-labeled analogs

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• 作者：Ze-Yu Yang ; Darrin Greenstein ; Eddy Y. Zeng ; Keith A. Maruya
• 关键词：Solid-phase microextraction (SPME) ; Poly(dimethyl)siloxane (PDMS)– ; water partition coefficient (K_f) ; Hydrophobic organic chemicals (HOCs) ; Radiolabelled analogs ; Mass balance
• 刊名：Journal of Chromatography A
• 出版年：2007
• 出版时间：27 April 2007
• 年：2007
• 卷：1148
• 期：1
• 页码：23-30
• 全文大小：461 K

文摘

Aqueous solutions of ¹⁴C-labeled analogs of seven hydrophobic organic chemicals (HOCs) were subject to solid-phase microextraction (SPME) under static conditions to assess their multi-compartment distribution and to compare poly(dimethyl)siloxane (PDMS)–water partition coefficients (K_f values) with previously reported values. To accomplish this, a protocol for quantitative desorption of radiolabelled HOCs from SPME fibers using hexane was developed. Time series extractions indicated that loading of SPME fibers had reached steady-state by day 8 for PCBs 52, 77 and 153, phenanthrene, benzo[a]pyrene, p,p′-DDT and p,p′-DDE. The recovery of spiked radioactivity among the (residual) aqueous phase, the PDMS coating, and all remaining wetted experimental surfaces ranged between 80 and 120 % . K_f values based on ¹⁴C-labeled analogs were in good agreement with previously published values that were determined at (or closely approaching) equilibrium conditions and without significant chemical depletion and/or uncorrected system losses. Because it allows for the direct determination of HOCs associated with the residual aqueous and experimental surface compartments, the use of radiolabelled HOC analogs is a powerful tool in discriminating among competing sorptive compartments encountered in most SPME fiber calibration methodologies employed to date.