Hybrid Organosilica Coatings for Solid Phase Microextraction: Highly Efficient Adsorbents for Determination of Trace Parabens

New hybrid organosilica coatings with different amount of alkyl functional groups on a quartz fiber for solid phase microextraction (SPME) have been obtained by the of sol-gel synthesis in the presence of polyethylene glycol (PEG). The structural-sorption properties of the synthesized silica coatings of various compositions have been studied. According to the thermogravimetric analysis, the main thermolysis of the adsorption coatings' organic layer was observed at temperatures higher than 350 degrees C. The effect of synthesis conditions on the thermal stability of the obtained PEG-based organosilica coating has been studied. It has been established that the textural characteristics of the produced coatings for SPME and their adsorption properties can be controlled using different PEG and silica precursors and the equivalence ratio in the reaction mixture. Good prospects of application of the fabricated coatings for SPME have been demonstrated in paraben extraction and concentration in aqueous solutions at 24 degrees C and pH 3.0-5.5 with their subsequent gas chromatography determination. The suggested technique was characterized by good accuracy and reproducibility (RSD <= 2.3%). Comparative studies of the obtained hybrid organosilica coatings for SPME with a commercially available fiber with a bipolar polymer coating-divinylbenzene/carboxen/polydimethylsiloxane-have been conducted.