Rapid analysis of trace pollutants using laser mass spectrometry

Organic pollution has been gaining more and more attention. Yet, at present the determination of virtually all of them, including polycyclic aromatic carbons (PAHs), the largest single class of chemical carcinogens known toda y, is made via pre-purification and pre-concentration. The major problems a re complexity and time-consuming, thus, no ideal real-time on-line monitori ng can be done. Laser mass spectrometry combines UV spectroscopy and time-o f-flight mass spectrometry (TOF-MS) through resonance-enhanced multiphoton ionization ( REMPI). It is characteristic of high sensitivity, high selecti vity and rapidity. In this paper, after its principles, a small mobile lase r mass spectrometer, In which a mini-excimer (KrF, 248 nm) laser was used, is introduced. Real-time analysis of vehicle exhaust gas was made using thi s instrument, and the results showed some advantages over traditional metho ds: multicomponent detection, including benzene, toluene, xylene, C-3-benze ne, naphthalene, and methyl-naphthalene; high sensitivity (100 ppb); high t ime-resolution (0.1 s); and no need for prepurification or pre-concentratio n of samples.