Development of a high-efficiency and environmentally friendly melamine–formaldehyde resin-based solid phase microextraction fiber for enhanced extraction of polycyclic aromatic hydrocarbons from environmental water

Abstract

An innovative solid-phase microextraction (SPME) fiber coating, melamine–formaldehyde resin (MFR), was synthesized with a green cross-linker (paraformaldehyde), and it exhibited high heat resistance (up to 350 °C). Seven polycyclic aromatic hydrocarbons (PAHs) were chosen as analytes, and the results demonstrated the MFR-based SPME fiber's exceptional enrichment capabilities and efficient extraction, with high enrichment factors and significantly improved efficiency compared to the conventional polydimethylsiloxane (PDMS) fibers. The unique superiority of the MFR was attributed to its strong π–π interactions and amino-associated enhancement, as well as its porous structure and rough surface, which provided abundant adsorption sites and facilitated rapid mass transport of analytes. Furthermore, the preparation conditions of the MFR-coated SPME fiber were compared with those of commercially available and reported fibers, emphasizing the advantages of the MFR-coated fiber, such as its simplicity, cost-effectiveness, reproducibility, and eco-friendliness. The MFR-based SPME fiber exhibited significant advantages, including high enrichment factors (ranging from 1906- to 7153-fold) for PAHs and good fiber-to-fiber reproducibility (8.7–14.6%), outperforming commercially available PDMS fibers by a factor of 4.9–82.8-fold. This study also considered important factors affecting the extraction process, such as ionic strength, temperature, and time, and optimized these parameters for the best extraction efficiency. The greenness of the developed method was assessed using the Analytical Eco-Scale, and the results showed that it was green in terms of reagent dosage, energy consumption, and waste. The developed headspace solid phase microextraction–gas chromatography–tandem mass spectrometry (HS-SPME-GC-MS/MS) method based on the MFR coating exhibited excellent precision, accuracy, and repeatability, making it a reliable method for the determination of trace PAHs in environmental water samples.