In torchlaser ablation sampling for inductively coupled plasma mass spectrometry

Abstract

An inductively coupled plasma mass spectrometer (ICP-MS) was modified to allow direct in torch laser ablation experiments. In this setup a sample was placed at the tip of the injector tube where the ablation took place. The laser beam was focused orthogonally through the ICP torch onto the sample surface. The ablated material caused transient signals of a few milliseconds in duration in the quadrupole ICP-MS system. The setup allows comparison with conventional laser ablation (LA) ICP-MS where the sample is placed in an ablation cell and the aerosol is transferred to the ICP via plastic tubing. The same number of counts per laser shot were measured for both sample introduction systems. However, the limit of detection (LOD) for uranium in glass (NIST SRM 610) was improved by two orders of magnitude, which is caused by the significantly reduced dispersion of the aerosol entering the plasma.