The enhancement of surface area and porosity of polymer
structure, being synthesized as a sorbent, more probably improves
the extraction efficiency. The use of inorganic nanoparticles in
polymer structure is an efficient path to fulfill this purpose. For
investigating the effect of NiO nanoparticles doping level on the
extraction capability, five NiO-PBT nanocomposites were prepared
doped with 0.001, 0.005, 0.010, 0.015 and 0.020 g of NiO nanoparticles.
According to Fig. 2b, the extraction capabilities of the
NiO-PBT nanocomposite were enhanced as the NiO nanoparticles
content was increased. These results revealed that the NiO nanoparticles
doping level has an important role in the sorbentextraction
ability. Apparently formost analytes, increasing the NiOdoping level
up to 0.020 g leads to an improvement in extraction efficiency,while
at values higher than 0.020 g, the electrospining process becomes
ratherdifficulttoperform.Accordingtotheseresults,adopinglevelof
0.020 g was chosen as the optimum value. The SPME coating
thickness can be controlled by the electrospinning timeand as itwas
increased, the fiber coating became thicker, providing a higher
extraction capacity. Considering Fig. 2c, the time of electrospinning
was selected at 3 minwhich led to the formation of a coating with a
suitable thickness and providing a SPME fiber within a short while.