Poly-epsilon-caprolactone nanofibrous polymers: A simple alternative to restricted access media for extraction of small molecules from biological matrixes.

Poly-epsilon-caprolactone nanofibrous polymer has been used as an alternative to restricted access media for extraction of proteins-containing biological samples and direct transfer in the chromatographic system. Three commercial cartridges differing in length and i.d. have been manually packed with the composite material prepared from poly-epsilon-caprolactone nanofibers coated on poly-epsilon-caprolactone microfibrous scaffold and connected to the column-switching chromatographic system. The bovine milk and human serum (25 microL) spiked with a mixture of methyl-, ethyl-, propyl-, and butylparaben in a concentration range of 1-100 microg mL-1 were on-line extracted using the cartridge containing fibers. Then, 5 and 20% (v/v) aqueous methanol was applied as the washing mobile phase. While the ballast protein macromolecules were quantitatively eluted from the nano-/microfibrous composite sorbent, the parabens were retained. After switching the mobile phase to a stronger one, these compounds were then eluted from the extraction sorbent, directed in the analytical column, and finally separated. An extraction efficiency of 86-101% for all parabens achieved using the optimum-sized cartridge and a repeatability of the extraction procedure of 0.06-1.95% RSD were monitored.