Carboxylated solid carbon spheres as a novel solid-phase microextraction coating for sensitive determination of phenols in environmental water samples

• SCSs-COOH as a SPME material shows high extraction efficiency for polar phenols.
• The coating shows high thermal stability (>330 °C) and enrichment factors (300–1904).
• Simplification due to no derivatization requirement.
• The developed method achieved low limits of detection (0.26–2.63 ng L−1).

The high performance separation and enrichment of polar phenols from aqueous matrices is often difficult due to the strong interactions between phenols and water. In this paper, carboxylated solid carbon spheres (SCSs-COOH) were, for the first time, used as a novel coating material in the solid-phase microextraction (SPME) of polar phenols at ultra-trace levels in environmental water samples. Gas chromatography coupled with tandem mass spectrometry (GC–MS/MS) was applied for sample quantification and detection. The novel SCSs-COOH-coated fiber exhibited good thermal stability (>330 °C) and higher extraction efficiency than commercial fibers in the extraction of phenols. The Plackett–Burman design was employed to optimize the extraction factors affecting the extraction efficiency through a response surface methodology. A possible phenol extraction mechanism enabled by the SCSs-COOH-coated fiber is proposed. Under the optimized conditions, low detection limits (0.26–2.63 ng L−1), a wide linear range (1–1000 ng L−1), good repeatability (2.00–9.02%, n = 5) and excellent reproducibility (2.08–8.55%, n = 3) were achieved. The developed method was validated against several environmental water samples, with satisfactory results being obtained each case.