Electrospun nanofibrous solid-phase microextraction coatings for preconcentration of pharmaceuticals prior to liquid chromatographic separations.

Electrospun epoxide polymer and carbon nanofiber-based SPME phases were examined for their application to the direct extraction of nonvolatile analytes coupled to liquid chromatography (LC). All of the electrospun nanofiber-coated SPME fibers demonstrated superior extraction efficiencies which were 2-32 times higher than a commercially available SPME fiber, with the electrospun coating processed at 800°C demonstrating the highest extraction efficiency. The carbonized electrospun nanofiber-coated SPME fibers showed no swelling when immersed in a variety of liquids, demonstrating the improved chemical stability these coatings have over traditional polymer-coated SPME fibers, which typically swell during direct extraction. Additionally, these robust coatings exhibit prolonged fiber lifetimes, withstanding up to 100 direct extractions without significant damage or change in nanofiber morphology. The detection limits of the method were found to be 2-3 orders of magnitude lower than those reported when using commercially available polyacrylate (PA) SPME fiber under similar conditions.