SIMULTANEOUS DETERMINATION OF 11 POLYCYCLIC AROMATIC-HYDROCARBONS (PAHS) BY 2ND-DERIVATIVE SYNCHRONOUS SPECTROFLUOROMETRY CONSIDERING THE POSSIBILITY OF QUENCHING BY SOME PAHS IN THE MIXTURE

A method capable of determining 11 PAHs (acenaphthene, anthracene, ben z[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluorant hene, chrysene, phenanthrene, fluoranthene, indeno[1,2,3-cd]pyrene and perylene) in a mixture of 18 by second-derivative synchronous spectro fluorimetry 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 mo lecules 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]pyre ne. Other papers related to complex mixtures have not taken this possi bility into account; on the other hand, the identification and quantif ication of PAHs in such a complex mixture (18 compounds) has never bee n 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 detect ion limit of 4.95 ng ml(-1)) and a short analysis time (four PAHs were determined in one interval alone, Delta lambda = 95 nm), the total id entification and quantification of the PAHs taking only 10 min.