Determination of polynuclear aromatic hydrocarbons in vapor phases by laser-induced molecular fluorescence

Abstract

Laser-induced molecular fluorescence (l.i.m.f.) is shown to be a highly sensitive and selective technique for the dynamic quantitation of polynuclear aromatic hydrocarbons (PAH) in the vapor phase. A plot of log (fluorescence intensity × temperature) vs 1/ T for anthracene is linear over five orders of magnitude; fluoranthene exhibits a linear dependence over four orders of magnitude. The vapor pressures of anthracene and fluoranthene were determined from 25 to 150°C and 25 to 105°C, respectively. The vapor pressures of anthracene and fluoranthene were 9.10 × 10 −9 atm and 3.55 × 10 −8 atm, respectively, at 25°C. It is feasible to quantify anthracene and fluoranthene in a mixture by using the time delay and emission wavelength selectivity of l.i.m.f.