Analytical interest in nitrated polycyclic aromatic hydrocarbons
(nitro-PAHs) is related to their high mutagenicity and potential
presence in a variety of environmental media such as diesel
exhaust and urban air particulate matter. Furthermore, fundamental
interest in these molecular systems stems from the photophysics
of the labile NO2 functional group, which has been
investigated using mass spectrometry. The nitro-PAHs,
1-nitronaphthalene, 9-nitroanthracene, and 1-nitropyrene, have
been studied using both femtosecond (λ = 395 and 790 nm)
and nanosecond (λ = 266 nm) lasers coupled to a reflectron
time of flight mass spectrometer. Analysis of mass spectra taken
over a range of intensities (1014–1015
W/cm2) has demonstrated that structurally specific ions
can be observed for each molecule, with little or no fragmentation
at lower intensities. It has also been found that an intact parent
ion can be detected using femtosecond ionization at 395 nm in each
case. This work demonstrates the potential use of laser
desorption/femtosecond laser mass spectrometry (LD/FLMS) as an
analytical technique for the detection of nitro-PAHs and other
environmental pollutants and as a means of studying the photodynamics
of labile molecular systems.