Comparative study of the sol-gel based solid phase microextraction fibers in extraction of naphthalene, fluorene, anthracene and phenanthrene from saffron samples extractants

We are introducing a method for the determination of some polycyclic aromatic hydrocarbons in aqueous saffron sample by direct immersion solid phase microextraction (SPME) and gas chromatography. A sol-gel technique is used for the preparation of the SPME fibers. Three kinds of sol-gel coatings on the fibers were tested and compared. They are composed of poly(dimethyl siloxane) (PDMS), poly(ethylene glycol) (PEG), and a poly(ethylene glycol) modified with multi-walled carbon nanotubes (PEG/CNTs). The effects of fiber coating, desorption time, desorption temperature, extraction time, stirring speed and salting effect were optimized. Under the optimal conditions, the detection limits (at S/N = 3) are 7-50, 5-50, and 1-10 pg mL(-1), respectively, for SPME fibers made from PDMS, PEG and PEG/CNTs. The relative standard deviations for one type of fiber are from 2.1% to 9.6% for all fibers (at n = 5), and in the range from 1.9% to 9.8% from batch to batch (for n = 3).