Polysiloxane coated steel fibers for solid-phase microextraction of chlorobenzenes

We report on a nanostructured polysiloxane as a coating for solid-phase microextraction (SPME) of chlorobenzenes from water, wastewater, sludge and sediment samples. Methyltriethoxysilane was used to prepare the nanostructured fibrous polysiloxane coatings, which were deposited onto a stainless steel wire. Headspace SPME, followed by GC with electron capture detection was applied for separation and quantitation. The effects of stirring rate, salt concentration, equilibrium and extraction time, extraction temperature, desorption time and temperature were optimized. The extraction efficiency of the analytes using the new fiber was 5-10 and 10-30 times better than those obtained by using the commercial PDMS fiber and nonfibrous polysiloxane fiber, respectively. The relative standard deviations for intra- and inter-day precision for a single fiber were below 6 %. The fiber to fiber reproducibility was in the range of 3.3-9.7 % (for n = 3). The detection limits were between 0.15 and 75 ng L-1. The relative recoveries for water, wastewater, sludge, and sediment samples were in the range from 90 to 99 %.