Carbon nanotube-coated solid-phase microextraction metal fiber based on sol–gel technique

A novel carbon nanotube (CNT)-coated solid-phase microextraction fiber was prepared based on sol–gel technique. Commonly used fragile fused silica fiber was replaced with stainless steel wire, which made the fiber unbreakable. An approach was also proposed for batch producing, and good reproducibilities for fiber to fiber and between fibers were achieved. Experiments showed that the sol–gel-CNT fiber exhibited high thermal stability to resist 350 °C and excellent solvent durability in methanol and acetonitrile. Compared to commercial polydimethylsiloxane (PDMS) fiber, the sol–gel-CNT fiber represented significantly improved extraction efficiencies for both polar (phenols) and non-polar (benzene, toluene, ethylbenzene, and o-xylene) compounds. Meanwhile, no replacement effect, low carry-over and wide linear range demonstrated that the newly prepared sol–gel-CNT coating has liquid properties, which allow a relatively easy quantification procedure. Moreover, the characterization of the sol–gel-CNT coating was also evaluated with McReynold probe solutes. The results showed that the coating has better affinity for all the five types of solutes compared to commercial 7 μm PDMS fiber, which suggested that the coating has the potential to be developed as GC stationary phase.