[The enrichment of polycyclic aromatic hydrocarbons in water samples by solid-phase extraction]

Solid-phase extraction (SPE) is an emerging chromatographic sample preparation technique. The novel extraction technique can reduce the time and volume of organic solvents required, and alleviate problems associated with the formation of emulsions as compared to conventional liquid-liquid extractions. This study was designed to demonstrate the utility of SPE for trace enrichment of polycyclic aromatic hydrocarbons (PAHs) in water samples. The results showed that dichloromethane and benzene are the preferred elution solvents for the adsorbed PAHs. The recoveries of PAHs with SPE are in the range of 87% to 102%. When the elution solvent is selected, the variation of recoveries as a function of the volume of elution solvent used can be determined. Meanwhile, further studies showed that recoveries become worse as the number of rings of PAH increased. The decrease of solubility and adsorption onto container surface may be responsible for bad recoveries. The addition of 20% (V/V) methanol or ethanol into the sample prior to spiking can greatly improve the recoveries of larger PAHs. Recoveries of 89%-108% can be obtained.