Imprinted silica nanofiber formation via sol–gel electrospinning for selective micro solid phase extraction
Sara asgari, Habib Bagheri, Ali Es-Haghi
New Journal of Chemistry, 42 (2018) 13864-13872
doi: 10.1039/
c8nj01818a
Sol composition and ripening conditions are two important parameters in silica fiber production through the conventional sol–gel process. In the current study, silica nanofibers were successfully obtained via
the electrospinning technique, and sol–gel formation occurred during this process. Based on previous
reports, with the aim of increasing the selectivity, we used the molecular imprinted methodology to
produce a selective medium via sol–gel electrospinning. In this process, sol–gel was formed during
electrospinning and then, the backbone polymer was removed by heating. To obtain a thin layer of silica
nanofibers, the influencing parameters such as backbone polymer types, imprinting time and the
components ratio were explored. The data obtained from Fourier transform infrared spectroscopy and
thermogravimetric analysis revealed that the polyamide moiety was removed after heating. Also, the
scanning electron microscopy images indicated the geometry of the silica nanofibers before and after
heating. The extraction efficiency of the electrospun silica nanofiber mat was compared with the same
silica precursor sol–gel produced by bulk and electrochemical approaches. The data obtained from the
online micro-solid phase extraction-liquid chromatography analysis demonstrated the superiority of
the electrospun silica nanofibers. After optimizing the entire procedure, the method was validated. The
linearity of the analyte is in the range of 6–400 µg L-1, while the LOD value is 1.8 µg L-1 and the inter- and
intra-day RSDs% are less than 9.6%. The method was conveniently applied to the spiked and un-spiked
Zayanderood river, garden stream, and tap water samples with relative recovery percentages of up to 109%.