Preparation of a carbon fiber brush for solid-phase microextraction of petroleum hydrocarbons from environmental water samples.

BACKGROUND: Monitoring petroleum hydrocarbons (PHCs) in complex environmental matrices requires extraction materials that offer high sensitivity, robustness, and scalability. Solid-phase microextraction (SPME) fibers often suffer from limited surface area, inadequate chemical stability, and poor long-term durability, which restrict their performance in demanding analytical workflows. To overcome these limitations, carbon-based sorbents have gained increasing attention due to their thermal resistance and π-electron-rich structures. However, scalable preparation of high-surface-area architectures remains challenging. This work introduces an industrially viable strategy for constructing brush-like carbon fiber cluster (BLCF) SPME fibers with enhanced sorptive activity and operational stability.

RESULTS: The proposed preparation method employs polyacrylonitrile-based carbon fibers produced via controlled copolymerization, wet spinning, stabilization, and carbonization, followed by electrolytic oxidation and sizing to activate the surface. Around 600 ultrafine filaments were assembled into a clustered, brush-like microstructure, offering high flexibility, increased surface area, and a uniform strip-like morphology. They showed excellent solvent resistance, thermal stability up to 330 °C, and mechanical durability over more than 200 extraction-desorption cycles. In direct-immersion SPME-GC-FID, extraction efficiency improved by 4.2-10.4 times compared to a single carbon fiber. The method demonstrated linearity from 2 to 300 μg L-1 (R ≥ 0.992), low detection limits (0.15-3.46 μg L-1), and repeatability below 6.4%, with 81%-105% recoveries in river, sewage, and lake samples.

SIGNIFICANCE: This study presents a durable, scalable, and high-performance clustered carbon fiber platform for SPME, offering substantial improvements in hydrocarbon extraction and environmental analysis. The BLCF design combines industrial manufacturability with enhanced sorption capacity, effectively addressing the limitations of common SPME fibers. Its strong stability, reproducibility, and broad applicability highlight its potential as a versatile extraction medium for PHCs and other analytes in advanced analytical monitoring.