Simultaneous determination of 11 polycyclic aromatic hydrocarbons (PAHs) by second-derivative synchronous spectrofluorimetry considering the possibility of quenching by some PAHs in the mixture

A method capable of determining 11 PAHs (acenaphthene, anthracene, benz[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, chrysene, phenanthrene, fluoranthene, indeno[1,2,3-cd]pyrene and perylene) in a mixture of 18 by second-derivative synchronous spectrofluorimetry in the constant wavelength mode was developed. It has not been possible to determine the following PAHs in the mixture: dibenz[a,h]anthracene, fluorene, indene, naphthalene, pyrene, triphenylene and 1,12-benzoperylene. The possibility of selective quenching of some molecules by others in the mixture was considered and it was found that the fluorescent signal of fluorene is quenched by indeno[1,2,3-cd]pyrene. Other papers related to complex mixtures have not taken this possibility into account; on the other hand, the identification and quantification of PAHs in such a complex mixture (18 compounds) has never been attempted before. The approach studied allows the sensitive, rapid, easy and inexpensive identification and quantification of 11 PAHs in a solution of hexane. The detection limits are between 0.01 and 0.70 ng ml–1 in most cases (except for indeno[1,2,3-cd]pyrene with a detection limit of 4.95 ng ml–1) and a short analysis time (four PAHs were determined in one interval alone, Δλ = 95 nm), the total identification and quantification of the PAHs taking only 10 min.