Absorption of hydrophobic compounds into the poly(dimethylsiloxane) coating of solid-phase microextraction fibers: high partition coefficients and fluorescence microscopy images.

摘要

The use of solid-phase microextraction with poly(dimethylsiloxane) (PDMS)-coated glass fibres for the extraction and analysis of hydrophobic organic analytes is increasing. A new method, which minimizes the impact of experimental artifacts was applied to determine PDMS water partition coefficients of 17 hydrophobic analytes including chlorinated benzenes, PCBs, PAHs, and p,p'-DDE. These partition coefficients are several orders of magnitude higher than some reported values. Two observations strongly suggested that the retention of hydrophobic organic substances is governed by partitioning into the PDMS coating. The partition coefficients were proportional with octanol/water partition coefficients. The fluorescence of fluoranthene was observed to be homogeneously distributed within the polymer coating when studied by means of fluorescence microscopy. The implications of these findings for the application of solid-phase microextraction with respect to potential detection limits, with respect to biomimetic extraction, and with respect to measurements in multicompartment systems are discussed.