Heating‑, cooling‑ and vacuum‑assisted solid‑phase microextraction (HCV‑SPME) for efficient sampling of environmental pollutants in complex matrices

This research introduces a novel solid-phase microextraction technology, in which the features of heating of sample, cooling of sorbent, and extraction under vacuum condition have been merged. Heating-, cooling- and vacuum-assisted solid-phase microextraction (HCV-SPME) method was developed as an efficient solution for the direct extraction of volatile and semi-volatiles species in complex solid samples. HCV-SPME was coupled with an in-needle capillary adsorption trap (HCV-INCAT) and applied to the direct extraction of polycyclic aromatic hydrocarbons (PAHs) within soil samples. It consisted of polythiophene/carboxylic acid modified multi-walled carbon nanotube nanocomposite, which was synthesized and wall-coated within a platinized stainless-steel needle via electropolymerization. The influential experimental variables (desorption conditions, sample temperature, adsorption temperature, sampling flow rate, and vacuum level) on the extraction efficiency were optimized. The developed HCV-INCAT technique was used in conjunction with GC-FID and applied for the extraction and determination of PAHs in contaminated soil samples, closely matching with those obtained using a validated ultrasonic-assisted solvent extraction procedure. Under the optimal conditions, linear dynamic ranges, limits of detection, and relative standard deviations were obtained 0.007–5 µg g⁻¹, 8–20 pg g⁻¹, and 7.1–12.1%, respectively, for direct extraction of naphthalene, fluorene, phenanthrene, fluoranthene, and pyrene from solid samples.