Electrospun nanofibers-based thin film microextraction for enrichment of phthalate esters in biodegradable plastics

In this work, a novel electrospun nanofiber (PAN/TpBD; 2,4,6-triformylphloroglucinol [Tp] and benzidine [BD]; polyacrylonitrile [PAN]) was fabricated via a facile electrospinning method and utilized as adsorbent in thin film microextraction (TFME) of phthalate esters (PAEs) (dimethyl phthalate, diethyl phthalate, diallyl phthalate, dibutyl phthalate, and dioctyl phthalate) in biodegradable plastics. The prepared PAN/TpBD combines the strong stability of nanofibers with increased exposure sites for covalent organic frameworks and enhanced interactions with the target, thus improving the enrichment effect on the target. The extraction efficiency of PAN/TpBD reached above 80%. Based on PAN/TpBD, a TFME-high-performance liquid chromatography method was established, and the experimental parameters were optimized. Under the optimal extraction conditions, the PAEs of this method varied linearly in the range of 10-10 000 µg/L with low detection limits (0.69-2.72 µg/L). The intra-day and inter-day relative standard deviation values of the PAEs were less than 8.04% and 8.73%, respectively. The adsorbent can achieve more than 80% recovery of the five targets after six times reuse. The developed method was successfully applied for the determination of trace PAEs in biodegradable plastics with recoveries ranging from 80.1% to 113.4% and relative standard deviations were less than 9.45%. The as-synthesized PAN/TpBD adsorbent exhibited great potential in PAE analysis.