Determination of lower sub ppt levels of environmental analytes using high-powered concentration system and high-performance liquid chromatography with fluorescence detection

Abstract

The proposed method was successful in the determination and separation of lower sub ppt levels of polycyclic aromatic hydrocarbons (PAHs). In this study, a new phase separation phenomenon (i.e., homogeneous liquid–liquid extraction) was developed that rapidly and simply separated an immiscible liquid phase from water-miscible organic solvents. One liter of sample solution was preconcentrated by a solid phase extraction method, then the obtained eluate (5 mL) was further preconcentrated to just 20 µL by this homogeneous liquid–liquid extraction. The 20 µL sedimented phase was directly injected into the high-performance liquid chromatography with fluorescence detection (FL-HPLC). The entire preconcentration factor was 50,000-fold. Six kinds of PAHs were determined in the range of 3.0 × 10⁻¹⁸∼4.5 × 10⁻¹¹ mol L⁻¹. These chemicals were also satisfactorily separated.