Determination of phenolic compounds in water and urine samples using solid-phase microextraction based on sol-gel technique prior to GC-FID

In this research, a headspace solid-phase microextraction (HS-SPME) method, based on sol-gel poly(ethylene glycol) reinforced with multi-walled carbon nanotubes (PEG/CNTs) coated fiber, prior to gas chromatography-flame ionization detector (GC-FID), was proposed for the determination of phenolic compounds in water and urine samples. Under the optimized conditions, the linear range for phenol and cresols was 0.005-100 ng mL(-1), the limit of detection (S/N = 3) was 0.001 to 0.1 ng mL(-1) and the limit of quantification (LOQ) was 0.005 to 0.5 ng mL(-1). The relative standard deviations (RSDs) for one fiber (repeatability) (n = 5) were obtained from 5.4 up to 7.1%, and between fibers, or batch to batch (n = 3), (reproducibility) in the range of 8.3-10.5%. The proposed HS-SPME-GC-FID method was successfully applied for the extraction of phenol and cresols from complex matrices such as wastewater and urine samples. Relative recoveries ranged from 85.3 to 99.5% for water samples and from 95.2 to 101.1% for urine samples.