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

• Published in: Journal of Chromatography A Vol. 1148; no. 1; pp. 23 - 30
• Main Authors: Yang, Ze-Yu, Greenstein, Darrin, Zeng, Eddy Y., Maruya, Keith A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 27.04.2007; Elsevier
• Subjects: Analytical chemistry; Carbon Radioisotopes; Chemistry; Chromatographic methods and physical methods associated with chromatography; Dimethylpolysiloxanes - chemistry; Exact sciences and technology; Gas chromatographic methods; Gas Chromatography-Mass Spectrometry; Hydrophobic and Hydrophilic Interactions; Hydrophobic organic chemicals (HOCs); Kinetics; Mass balance; Organic Chemicals - analysis; Organic Chemicals - chemistry; Poly(dimethyl)siloxane (PDMS)–water partition coefficient ( Kf); Radiolabelled analogs; Reproducibility of Results; Solid Phase Microextraction; Solid-phase microextraction (SPME); Water - chemistry; Mass balance; Radiolabelled analogs; Poly(dimethyl)siloxane (PDMS)–water partition coefficient ( K f); Solid-phase microextraction (SPME); Hydrophobic organic chemicals (HOCs); Water; Carbon Isotopes; Partition coefficient; Chemical enrichment; Sample preparation; Organochlorine compounds; Chlorocarbon; Radiopharmaceuticals; Carbon 14; Dimethylsiloxane polymer; Phenanthrene; Hydrocarbon; Coupled method; Hydrophobic compound; Polycyclic aromatic compound; Polychlorobiphenyl; Solid phase microextraction; Gas chromatography; Pollutant; Mass spectrometry; Poly(dimethyl)siloxane (PDMS)-water partition coefficient (Kf)
• ISSN: 0021-9673
• DOI: 10.1016/j.chroma.2007.02.098

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.