Desorption atmospheric pressure chemical ionization (DAPCI) is implemented on a portable
mass spectrometer and applied to the direct detection of polycyclic aromatic hydrocarbons
(PAHs) and alkyl substituted benzenes. The presence of these compounds in the environment
poses a significant threat to the health of both humans and wildlife because of their
carcinogenic, toxic, and mutagenic properties. As such, instant detection outside
of the laboratory is of particular importance to allow in-situ measurement at the
source. Using a rapid, high throughput, miniature, handheld mass spectrometer, several
alkyl substituted benzenes and PAHs (i.e., 1,2,3,5-tetramethylbenzene, pentamethylbenzene,
hexamethylbenzene, fluoranthene, anthracene, benzo[k]fluoranthene, dibenz[a,h]anthracene,
acenaphthene, indeno[1,2,3-c,d]pyrene, 9-ethylfluorene, and 1-benzyl-3-methyl-naphthalene)
were identified and characterized using tandem mass spectrometry (MS/MS) from ambient
surfaces, in the open air. This method can provide almost instantaneous information
while minimizing sample preparation, which is advantageous in terms of both cost and
simplicity of analysis. This MS-based technique is applicable to a wide range of environmental
organic molecules.