Vortex- and Shaker-Assisted Liquid-Liquid Microextraction (VSA-LLME) Coupled with Gas Chromatography and Mass Spectrometry (GC-MS) for Analysis of 16 Polycyclic Aromatic Hydrocarbons (PAHs) in Offshore Produced Water

A simple, cost-effective, and efficient pretreatment method, namely, vortex-and shaker-assisted liquid-liquid microextraction (VSA-LLME) coupled with gas chromatography and mass spectrometry (GC-MS), is developed for determining 16 trace-level polycyclic aromatic hydrocarbons (PAHs) in offshore produced water. The parameters affecting the VSA-LLME performance including solvent volume, ion strength, shaking time, and centrifuge speed were optimized. Under the optimized condition, the enrichment factors range between 68 and 78. The method linearities (R-2) for all 16 PAHs were above 0.99 at concentration range between 10 and 200 ng/L. The recoveries of the method were 74-85 %, and the limits of detection were as low as 2 to 5 ng/L. The relative standard deviations (RSD%) were 6 similar to 11 %. The developed method was also validated in industrial wastewater sample and showed good capability in determination of 16 PAHs in offshore produced water. The developed method offers advantages including simplicity of operation, low cast, and high sensitivity.