Nanofibrous polyamide homopolymers and copolymers as advanced sorbents for on-line solid phase extraction coupled...

New polyamide (PA) homopolymers and copolymers nanofibers with different alkyl chain lengths as novel materials have been investigated for the automation of on-line sample preparation step and extraction of polycyclic aromatic hydrocarbons (PAHs) from the environment. PA 4/6 nanofiber copolymer showed the highest extraction yield of tested analytes and comparable performance with commercial reversed phase C18 sorbent. Our study presents an automation of on-line solid phase extraction method coupled with ultra-high performance liquid chromatography with fluorescence detection for the analysis of nine PAHs in river water. The optimal conditions included 50 μL injection volume, washing with 10 % acetonitrile at a flow rate of 1.0 mL min^-1 for 1 min, followed by backflush elution of analytes using a gradient of acetonitrile (from 60 % to 74 %) in water at 1.5 mL min^-1 over 12.25 min on a YMC-Triart PFP column (150 × 4.6 mm, 3 μm particle size). The total analysis time, including extraction, separation, and column equilibration, was 14 min. This method provides excellent analytical performance, with linearity ranging from 0.01 to 0.5 μg L^-1 for acenaphthene, anthracene, pyrene, chrysene, and 0.05-0.3 μg L^-1 for benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, indeno(c,d)pyrene and benzo(g,h,i)perylene, with coefficients of determination (R²) ranging 0.9989-0.9999. The limits of detection and quantification were 0.003-0.01 and 0.01-0.05 μg L^-1, respectively. The recoveries were between 92 and 105 %, with RSD 1.53-6.66 %. The polyamide-based sorbent requires no modification and can be inexpensively prepared as homogeneous mats by electrospinning. It can be cut and manually packed into a column or filtration device, allowing for easy replacement, when needed, with inter-columns repeatability of RSD <13 %. In addition, a single extraction column can be reused repeatedly.