POLYMER CHARACTERIZATION USING LASER DESORPTION-ION MOBILITY SPECTROMETRY

A series of polymer composite materials has been classified using lase r desorption-ion mobility spectrometry. The pulse from an Nd: YAG lase r ablates the surface of the composite polymer generating molecular fr agments in the vapour phase that are representative of the target mate rial. These vapour phase components are drawn into the ion mobility sp ectrometer source where they are ionized. Both positive and negative i ons are formed and the spectrometer can operate in either mode. The io ns are resolved into a pattern or signature characteristic of the poly mer. As the spectrometer can sample at a rate of approximately 1 s-1 a rapid method of identifying polymers results. Similar materials such as high and low density polyethylenes can be differentiated in this wa y.