Determination of Distribution Constants between a Liquid Polymeric Coating and Water by a Solid-Phase Microextraction Technique with a Flow-Through Standard Water System

摘要

This paper describes an optimized experimental system for determining water/polymer coating distribution con-stants and discusses the mechanism of extraction of high molecular weight compounds by poly(dimethylsiloxane) (PDMS). The proposed flow-through standard water gen-erator eliminates errors associated with both losses of analytes to the system surfaces and limited sample volume. In addition, the errors caused by partial precipi-tation or poor dissolution of highly hydrophobic analytes during spiking of water when producing calibration stan-dards are also eliminated. The target analytes are a range of polycydic aromatic hydrocarbons (PAils). The results demonstrate that absorption partitioning is the predomi-nant mechanism of extraction of analytes into PDMS-coated fibers for all PAHs investigated regardless of molecular weight There is a strong correlation between determined PDMS/water distribution constants (I4~) and literature K~ values for all PAHs.