Determination of Polycyclic Aromatic Hydrocarbons in Sediment by Pressure-Balanced Cold Fiber Solid Phase Microextraction

An improved performance of the cold fiber solid phase microextraction (CF-SPME) technique was accomplished with the use of the pressure-balanced procedure. In order to obtain a pressure-balanced state during extraction at 200 °C, 7 mL of air volume was withdrawn from 10 mL commercial vials, while 15 mL was withdrawn from vials where 5 μL of diethylamine was added as a modifier/displacer. The benefits of the balanced system were demonstrated for determination of polycyclic aromatic hydrocarbons (PAHs) from solid matrixes, including sand and certified sediment samples. Results showed the pressure-balanced procedure enhanced the extraction efficiency of the method, especially for high volatility compounds, as the leakage of analytes was mitigated under sample temperature conditions of 200 °C. Analytical precision was also improved, with relative standard deviations (RSDs) ranging from 4% to 8% for all analytes under study. For the determination of PAHs in certified sediment samples, pressure-balanced CF-SPME yielded more accurate results in comparison to nonpressure-balanced CF-SPME. The proposed methodology provided the additional benefit of improved recoveries at lower pressures.