Trace Pollutant Detection
We have investigated the potential of amplitude-modulation laser-photoacoustic scheme for the detection of trace pollutants in water. The technique has been found to be non-disturbing and easy-to-apply. In particular, the technique could be used to detect pollutants with a concentration corresponding to an absorption coefficient of 10-6cm-1. The sensitivity was found to be limited by a background signal resulting from light absorption by water. In addition to the amplitude-modulation scheme we also investigated the potential of a wavelength modulation scheme. Although this approach did reduce the background signal due to water absorption, we found the technique to be much more difficult to apply in practice.
Salamo, Gregory J. and Anderson, Richard J.. 1984. Laser-Photoacoustic Detection of Water Pollutants. Arkansas Water Resources Center, Fayetteville, AR. PUB102.