Silk fibroin nanofibers electrospun on glass fiber as a potential device for solid phase microextraction

Abstract

ABSTRACTThe electrospinning technique was applied to coat fused silica fibers with regenerated silk fibroin (RSF) nanofibers, aiming to build a device applicable for solid phase microextraction analysis. The device was characterized by attenuated total reflectance infrared spectroscopy, thermal analyses (differential scanning calorimetry and thermogravimetric analysis), and scanning electron microscopy, and employed to extract/desorb isopropyl alcohol (IPA) from the headspace of an IPA aqueous solution. The electrospun coating proved to be thermally stable up to 250°C, even after 4 h of exposure to this temperature. A 22 factorial experimental design was used to evaluate the flow rate of the polymer solution and the distance between capillary tip and collector on the mean RSF fiber diameter. A low flow rate (0.20 mL h−1) and large capillary tip‐to‐collector distance (12 cm) yielded fibers with mean diameter of (304 ± 46 nm). The nanofibers were heated to 250°C, simulating the conditions in the injector of a gas chromatograph (GC). In these conditions, the RSF nanofibers were found not to melt even after 4 h of exposure to heat, although slight structural damage was detected. Preliminary assays using the as‐constructed device built under optimized electrospinning conditions (0.20 mL h−1 and 12 cm) were performed in a GC by contact with the headspace of a 50 ppm IPA solution to determine the extraction and desorption times. The results indicated that the extraction process stabilized after 20 min of contact with the headspace of the IPA solution. The desorption process was complete after 10 min at 140°C. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41717.