Identification of organic compounds in ambient air via characteristic emission following laser ablation

The potential of laser-induced breakdown spectroscopy (LIBS) as a simple and rapid method for detection of organic compounds in ambient air was investigated. Ablation of samples of aromatic hydrocarbons and nitroaromatic compounds covering various surfaces was performed using the second (532 nm) or fourth (266 nm) harmonic of a nanosecond pulsed Nd:YAG laser. The plasma emission following the ablation consisted mainly of spectral features related to the CN (B2Σ+–X2Σ+) violet system and C2 (d3Πg–a3Πu) Swan system, and to some C, H, O, and N atomic lines. The CN, O and N lines include some contribution from the interaction of the ensuing plasma with background atmospheric air. There is a correlation between the intensity ratios of the products and the molecular structure, providing the possibility of identifying these compounds by LIBS.