In this research, the sol–gel technology was applied for the preparation of solid-phase microextraction fibers for extracting of methyl tert-butyl ether (MTBE) from environmental water samples. For this purpose, two different polymers such as poly(ethylene glycol) (PEG) and combination of PEG and multiwall carbon nanotubes (MWCNTs) were prepared using sol–gel technology as coating procedure for the fibers. The pre-concentration process followed by GC–FID determination was used and the results evidenced that pre-concentration factor for PEG/CNTs fiber was approximately five times higher than PEG. Parameters affecting the extraction efficiency such as temperature, extraction time, stirring speed and salt effect for each fiber were investigated and optimized. On the optimal conditions, the linear range for MTBE with PEG and PEG/CNT fibers were 10–3,000 and 1–1,000 ng mL-1 and the detection limits (S/N = 3) were 1.0 and 0.3 ng mL-1, respectively. The sol–gel PEG/ CNTs fiber has good performance and therefore relatively better figures of merit and experimental results such as thermal stability (up to 320 C), average of life time (over 150 times) and repeatability (RSD < 4) in comparison to conventional PDMS/Carboxen fiber, which was already reported for determination of MTBE.

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