Earth and Environmental Sciences (SEES)
Laser Ablation with ICP-MS
SEES use an ultraviolet laser beam to carefully extract small volumes of solid materials (minerals, bones, fossils etc), which are then transported to our ICP-MS via a stream of helium gas. The extracted particles are extremely small (< 1micron) and in the form of an aerosol, when this interacts with the argon plasma in the ICP-MS it is effectively ionized, i.e. the particles are dissociated into charged atoms and molecules.
The quadrupole mass analyser within the ICP-MS can then discriminate these ions on the basis of their mass and charge and the ratio between them. A detector counts these selected ions and we can turn these counts into a concentration within the sample of particular measured isotopes / elements and ratios between them. Due to the sensitivity of this technique we can measure trace elements down to a few ppm within small volumes of material and we can also measure U/Pb ratios within minerals such as zircon, titanite, monazite and allanite to determine their age.