A novel microfluidic device for fast extraction of polycyclic aromatic hydrocarbons (PAHs) from environmental waters - comparison with stir-bar sorptive extraction (SBSE)

摘要

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants renowned for their ubiquity in the environment and potential carcinogenicity. To verify compliance to the European Drinking Water Directive (98/83/EC) and Water Framework Directive (2000/60/EC), these compounds have to be monitored in environmental waters. Conventional laboratory analysis implies important costs and labour, and may lead to low sample representativeness due to sampling, transport and storage prior to analysis. To date, no portable equipment enables in situ PAH determination with adequate selectivity and sensitivity. To build a cost-effective and high-performance portable system, a microfluidic device for fast extraction of PAHs with low volume samples has been developed and tested by solvent desorption. Pre-concentration recoveries were evaluated by high-performance liquid chromatography associated with multi-wavelength fluorescence detection (HPLC-FLD). The operational parameters were optimised with 5 mu gL(-1) spiked solutions. The pre-concentration of 10mL solutions with the microfluidic device led to equivalent extraction recoveries to stir-bar sorptive extraction (SBSE) for the high molecular weight PAHs (4 aromatic rings) in approximately 50 times less time. The performance of the microchip has to be improved for the lightest PAHs (2-3 aromatic rings) by testing larger microchips and by using a more polar material than polydimethylsiloxane. Influence of matrix effects was also investigated by testing the device with artificial surface waters (mineral water supplemented with humic acids) and real samples (filtered lake water).