Simultaneous laser-induced multiphoton ionization and fluorescence for analysis of polycyclic aromatic hydrocarbons

Laser multiphoton ionization (LMPI) and laser-induced fluorescence (LIF) techniques were simultaneously applied to analysis of polycyclic aromatic hydrocarbons (PAH) in apolar solution. This combination of single-photon (LIF) and multiphoton (LMPI) processes provides unique information which is shown to be sufficient for both identification and quantification of PAH molecules in simple mixtures. We suggest 3D calibration plots (concentration as a function of both LMPI and LIF signals) where each PAH compound is represented by a unique vector in this space. The projections of such vectors onto the LMPI-LIF plane are the basis of PAH analysis, where only two measurements (LMPI and LIF signals) are required for speciation and quantification of a single component. A geometrical algorithm for decomposition of simple PAH mixtures, is also addressed.