Solvent-induced photodegradation as a source of error in the analysis of polycyclic aromatic hydrocarbons

The photodegradation of seven common polycyclic aromatic hydrocarbons (PAHs) has been examined in a range of organic solvents. Reactions followed a first order equation with benzo[a]pyrene and benzo[a]anthracene being the most rapidly photodegraded. Generally, the more polar the solvent the faster is the degradation process. A number of photodegradation products were identified by gas chromatography-mass spectrometry. The identification of compounds such as 4-amino-1-naphthalenecarbonitrile and 1H,3H-naphtho[1,8-cd]pyran-1-one clearly indicated that the solvent molecules have taken part in the formation of these compounds. Solvent-induced photodegradation is shown to be an important consideration in choosing the optimum solvent for the best analytical recoveries of PAHs from various matrices.