Determination of polycyclic aromatic hydrocarbon residues in water by synchronous solid-phase spectrofluorimetry

The polycyclic aromatic hydrocarbons (PAHs) benzo[a]pyrene (BaP), benzo[a]anthracene (BaA) and pyrene (Pyr), which exhibit native fluorescence in solution, were determined in water at trace levels by solid-phase spectrofluorimetry. The relative fluorescence intensity of BaP, BaA and Pyr fixed on Sephadex G-25 gel was measured after packing the gel beads in a 1 mm silica cell. By using the synchronous spectra at different values of Δλ, BaA, BaP and Pyr can be simultaneously determined in the presence of other PAHs. Spectral characteristics of the PAH–gel system are described. The concentration ranges over which the method was applicable were 0.3–2.5 ng ml–1 of BaP, 0.4–3.5 ng ml–1 of BaA and 0.5–4.5 ng ml–1 of Pyr with relative standard deviations of 1.4, 1.3 and 1.5% for BaP, BaA and Pyr, respectively. The detection limits were 0.03 ng ml–1 of BaP, 0.05 ng ml–1 of BaA and 0.08 ng ml–1 of Pyr. The method was applied to the analysis of waters from different sources.