Detection of polycyclic aromatic hydrocarbons in a soil sample with photon ionization technique.

An electron beam pumped rare gas excimer lamp (EBEL) was utilized to emit the intensive vacuum ultraviolet (VUV) radiation at 126 nm for soft single photon ionization (SPI) of polycyclic aromatic hydrocarbons (PAHs) in a soil sample. The VUV light source was coupled to a compact and mobile time-of-flight mass spectrometer (TOFMS) for the on-line measurement of PAHs. The moderate desorption temperature was set at 300 °C to guarantee the rapid evaporation of the PAHs in the soil sample and without decomposition from the larger molecules. With the thermal treatment, sample extraction and cleanup steps were not needed. The system developed herein was found to perform sufficiently well to evaluate the PAHs in the environmental soil sample at ppm level