Electrospun polyacrylonitrile nanofibers as fiber coating in solid phase microextraction

Abstract

Solid-phase microextraction (SPME) is widely used to preconcentrate analytes from sample. In this research, the polyacrylonitrile (PAN) nanofibers were fabricated on a metal wire via electrospinning method and used as a fiber coating for a homemade SPME unit. The SEM images show that the fiber coating’s surface was porous, and homogeneous. The average nanofibers diameter were 165 nm to 464 nm with PAN concentration from 3 to 10 %w/v. The homemade SPME unit was then applied for the extraction of 6 polycyclic aromatic hydrocarbons (PAHs) in water by headspace technique. Then it can directly transfer and desorb in the GC injection port by thermal desorption and analyzed by GC-FID. The optimum extraction condition was extraction time of 30 minutes, extraction temperature of 40 ◦C, and NaCl addition of 10% w/v. Desorption time and desorption temperature were optimized at 5 min and 200 ◦C, respectively. The percentage of recoveries of spiked water at 40 µg/L were 95.8 - 115.1 % with %RSD less than 12.7% for 5-PAN SPME fiber and 80.3 - 108.6% with %RSD less than 7.4% for 7-PAN SPME fiber. In addition, the good linearity for the analysis of 6 PAHs by 5-PAN and 7-PAN SPME fibers were in the range of 5 - 75 µg/L with R2 between 0.9697 and 0.9954 for 5-PAN and 5 - 75 µg/L with R2 between 0.9797 and 0.9956 for 7-PAN. The LODs were 0.08 - 0.5 µg/L for 5-PAN SPME fiber and 0.1 - 0.9 µg/L for 7-PAN SPME fiber. For durability, a homemade SPME fibers can reuse up to 20 times. Finally, the electrospun PAN SPME fibers were applied to extract PAHs in trace level (60 µg/L) from real water samples. The %recovery of extraction of PAHs ranged from 53.6 – 155.4 %.