Solid-Phase Microextraction Using Fused-Silica Fibers Coated with Sol−Gel-Derived Hydroxy-Crown Ether

Abstract

A novel solid-phase microextraction (SPME) fiber containing hydroxydibenzo-14-crown-4 (OH-DB14C4)/hydroxy-terminated silicone oil (OH-TSO) was first prepared by a sol-gel method and investigated for the determination of phenols. The possible mechanism is discussed and confirmed by IR spectra. The coating has stable performance in high temperature (to 350 degrees C) and solvents (organic and inorganic) due to the chemical binding between the coating and the fiber surface. The addition of crown ether enhances the polarity of the coating compared with that of the sol-gel OH-terminated silicone oil fiber and, accordingly, provides higher extraction efficiency for polar phenolic compounds. On the other hand, OH-terminated silicone oil in the coating can not only increase the length of network but also help to spread the stationary phase on the silica surface uniformly. The fluorescence microscopy experiment suggests the benefit the more uniform surface of the sol-gel-derived OHDB14C4/OH-TSO fiber in comparison with sol-gelderived OH-DB14C4 fiber. Some parameters of the SPME fiber for the determination of phenols were investigated. Limits of detection of the phenols are below 1.0 ng/mL, and the precisions are from 2.9 to 4.6% (n = 6). Linear ranges were found to be 0.1-10 microg/mL The sensitivity of the method is enhanced at a low-pH level (pH approximately 1) and with the addition of salt. The method was applied to the analysis of wastewater sample from a paper mill.

Preparation of stir bars for sorptive extraction using sol–gel technology

“…The precursor in this sol-gel process is much less than that of reported previously [22,26,28], in which a compact sol-gel is created and vortexed thoroughly before adding catalyst TFA, resulting molecular level mixing. A loose sol-gel network is formed because of the incorporation of more OH-PDMS after adding TFA.…”

Recent Developments and Applications of Microextraction Techniques for the Analysis of Pesticide Residues in Fruits and Vegetables

“…Due to their relative low recommended operating temperature (200 -300 O C) of the commercially available fiber, the recent trend is focused on the development of new fibers using sol-gel technology, with high thermal stability (>320 O C) [27][28][29][30][31][32][33][34][35][36][37] and molecular imprinted polymers (MIPs) [38][39][40][41][42]. Ionic liquids and sol-gel prepared ionic liquid coated fibers have also been recently developed and have been used extensively for the SPME extraction of pesticide residues in water samples [43][44][45][46], but their use for the extraction of analytes from food samples is a potential research area to be explored in the future.…”

Determination of organophosphorus pesticides in cucumber and potato by stir bar sorptive extraction

“…The sol-gel coating technology posses the potential to prepare thermally stable coatings [18][19][20]. Recently, we reported the preparation of the extraction phase on stir bar by sol-gel coating method and showed that the phase could with- stand 300 • C in either hydrogen or nitrogen gas atmosphere [21].…”